Morphometric correlations and body mass regressions for Armandia maculata, Aglaophamus macroura (Polychaeta), and Zethalia zelandica (Gastropoda) - Brian Paavo; Agnès Ziegelmeyer; Erika Lavric; P. Keith Probert (New Zealand Journal of Marine and Freshwater Research, 2008)
Armandia maculata and Aglaophamus macroura (Polychaeta) and Zethalia zelandica (Gastropoda) are abundant and conspicuous members of sandy sediment macrofaunal assemblages near dredge spoil disposal areas in southeast New Zealand. Regressions derived from data obtained by image analysis of preserved A . macroura specimens revealed that several dorsal width and area parameters of anterior chaetigers were related to total length (TL), estimated fresh weight (eFW), and ash‐free dry weight (AFDW). Length measurements were less reliable. These findings allow the development of processing protocols which use fragmented material. Total area (regardless of orientation) was related to AFDW in Ar. maculata which rarely fragment in collections. Maximum shell width was an efficient predictor of AFDW for Z. zelandica . If chosen as indicator species, these regressions allow partial automation and rapid processing of material for disposal impact studies using biomass and demographic approaches.

Dietary analysis of Coryphaenoides serrulatus, C. subserruiatus and several other species of macrourid fish (Pisces: Macrouridae) from northeastern Chatham Rise, New Zealand - M. R. L. Jones (New Zealand Journal of Marine and Freshwater Research, 2008)
The diets of Coryphaenoides serruiatus, C. subserruiatus and 11 other macrourid fish species sampled at depths of 901–1196 metres from the northeastern Chatham Rise are reported. Examination of stomach and intestinal contents of these fish permitted dietary reconstruction of species typically with high stomach‐eversion rates, and description of novel dietary information; the diets of all these species were dominated by small invertebrates, particularly Crustacea and Mollusca. The diets of C. serruiatus and C. subserruiatus were subject to ontogenetic change, with larger food items increasing in importance in the diet of larger fish. Benthic food items are important for some species, whereas overall the diets probably reflect seasonal levels of prey or carrion abundance.

Quantitative characterisation of reef fish diversity among nearshore habitats in a northeastern New Zealand marine reserve - Gareth J. Williams; Matthew J. Cameron; John R. Turner; Richard B. Ford (New Zealand Journal of Marine and Freshwater Research, 2008)
The influence of habitat type upon reef fish assemblage structures has been extensively reported, but there is still a need to quantitatively demonstrate the factors driving reef fish assemblages within and among habitats. This mensurative study examined diversity and community composition of reef fish assemblages between five habitats (shallow kelp, deep kelp, sand, algal turf, and sponge fiats) within the Cape Rodney‐Okakari Point Marine Reserve, northeastern New Zealand. Two contrasting sampling techniques, point count and timed search were used to quantify a range of species with different life history strategies and characteristics. Diversity generally decreased from kelp to sand habitats. Different habitat types displayed significantly different assemblages irrespective of the sampling technique used, as tested using two different multivariate techniques: constrained canonical analysis of principal coordinates and analysis of similarities (CAP, ANOSIM). Differences in depth between defined habitat types explained a significant proportion of variability in fish assemblage data (17% and 28% for the point count and timed search data, respectively), although a large proportion of variability was unexplained. A core group of species were found to be best discriminators among habitats, including Meuschenia scaber, Parapercis colias, Upeneichthys lineatus, Cheilodactylus spectabilis, Notolabrus celidotus, Notoclinops segmentatus, Forsterygion lapillum, and F. varium . Sand habitat was characterised by a general absence of species. This study examined analytical methodology for characterising reef fish assemblages using existing statistical procedures and demonstrates the ability to detect significant differences in fish communities among different nearshore habitats along the northeastern coast of New Zealand. Further monitoring and measuring of other environmental parameters would allow the creation of an explanatory model for relative fish community abundances for the northeastern coast of New Zealand.

Zinc sulfate and atrazine toxicity to the marine harpacticoid copepod Robertsonia propinqua - Lisa A. Hack; Louis A. Tremblay; Steve D. Wratten; Guy Forrester; Vaughan Keesing (New Zealand Journal of Marine and Freshwater Research, 2008)
Nauplii and adults of Robertsonia propinqua , a marine sediment‐dwelling copepod, were used in 96‐h static range‐finder toxicity tests to assess the lethal concentration at which 50% of test organisms are killed (LC 50 ) by atrazine (a herbicide) and zinc sulfate. Atrazine and zinc sulfate were used at concentrations near LC 50 values published for crustaceans. LC 50 values for R. propinqua nauplii were 1.5 mg/litre for atrazine and 1.7 mg/litre for zinc sulfate, respectively. For R. propinqua adults, the corresponding values were 31.8 mg/ litre for atrazine and 2.7 mg/litre for zinc sulfate. Robertsonia propinqua nauplii were more sensitive than adult life stages to exposure to both compounds, implying that the juvenile life stages are more sensitive to pollutants. These tests provided some evidence that both atrazine and zinc sulfate may be affecting the reproduction of R. propinqua owing to the reduced juvenile survival rates in the acute tests. The data for atrazine and zinc sulfate have important implications for the development of R. propinqua as a bioindicator of aquatic contamination. The range‐finding LC 50 results provide the basis for the determination of a realistic environmental concentration gradient for application in future definitive LC 50 and chronic full life cycle toxicity tests.

Environmental variability and population dynamics of juvenile brown trout ( Salmo trutta ) in an upstream and downstream reach of a small New Zealand river - Esben A. Kristensen; Gerard P. Closs (New Zealand Journal of Marine and Freshwater Research, 2008)
Population densities, size and condition factor of juvenile brown trout and variation in environmental factors (discharge, temperature, and food availability) were examined over 2.5 years (28 months) in an upstream and downstream reach of Silverstream, a lowland river in New Zealand. Population densities of juvenile brown trout varied between the upstream and downstream reach, with the latter showing considerably higher temporal variation in fish density than the upstream reach. Juvenile brown trout from the downstream reach were larger and had higher condition factors than those from the upstream reach over the study period. Discharge had a negative effect on fish densities in 1 year in the downstream reach, and high water temperatures were recorded in one summer, with possible negative effects on fish densities. However, the different effects of environmental variables on populations between the two reaches could not explain the higher temporal variation in fish densities in the downstream reach as spatial variation in population densities also occurred in years without high discharge events or high summer water temperatures. Variability in food availability over time was higher in the upstream reach, but differences between the two reaches were small. These results suggest that factors other than condition of the local environment are important in controlling brown trout population dynamics in Silverstream.

Physical microhabitat effects on 3‐dimensional spatial variability of the hydrobiid snail, Potamopyrgus antipodarum - Joseph R. Holomuzki; Barry J. F. Biggs (New Zealand Journal of Marine and Freshwater Research, 2007)
We studied how sediment size and current velocity affect epi‐ and endobenthic spatial variability of the hydrobiid snail, Potamopyrgus antipodarum , on New Zealand's South Island. A multi‐stream survey showed that P. antipodarum densities were lowest on gravel and highest on cobbles, and that densities on stones and sand were comparable. Sand patches were associated with the lowest current velocities, which likely enhanced the suitability of this microhabitat for snails. Snail densities in sample reaches (averages 19 to 442 individuals/m 2 ) sharply declined at current velocities above c. 15cm/s, suggesting a velocity‐density threshold. A colonisation experiment conducted in a slow‐velocity run revealed that more P. antipodarum use subsurface sediments than surface sediments, and that frequency of subsurface use may be habitat‐mediated. Approximately 80% of snails on gravel, pebbles, and cobbles used subsurfaces, whereas only c. 50% of snails in sand occupied subsurfaces. A laboratory flume experiment showed that snails burrow into sand even at relatively slow current velocities (18cm/s) apparently to avoid hydraulic forces or abrasion. Our results suggest that the large portion of snails occupying sediment subsurfaces must be accounted for in an accurate population census. Our findings also imply that Potamopyrgus surface densities could increase significantly, and possibly threaten local biodiversity, when the areal extent of slow velocity zones are increased by natural or human‐caused flow reductions.

On the growth of the European spiny lobster, Palinurus elephas from Sardinian waters (central western Mediterranean Sea) - Maria Cristina Follesa; Danila Cuccu; Rita Cannas; Angelo Cau (New Zealand Journal of Marine and Freshwater Research, 2007)
Growth of spiny lobsters Palinurus elephas was investigated using tagging data. A total of 4044 lobsters were tagged and released between 1997 and 2004 in an area off central‐western Sardinia, Italy, where fishing is banned. The growth increments of 248 lobsters, recaptured inside the no‐take area and in the surrounding zones, were recorded and analysed with two different procedures, and von Bertalanffy growth parameters were estimated for each sex. Males showed a higher asymptotic carapace length than females (167.9 versus 120.2mm). Growth increments recorded inside and outside the no‐take area did not reveal any density‐dependent effects on females. Small but non‐significant differences were evident for males, showing faster growth in lobsters caught outside the no‐take area.

Occurrence and distribution of Chilean dolphin (Cephalorhynchus eutropia) in coastal waters of central Chile - María José Pérez‐Álvarez; Emilia Alvarez; Anelio Aguayo‐Lobo; Carlos Olavarría (New Zealand Journal of Marine and Freshwater Research, 2007)
The Chilean dolphin, Cephalorhynchus eutropia , is an endemic species distributed along the central‐southern coast of Chile. Biological and ecological knowledge about this species is insufficient; it is catalogued as Data Deficient “DD” by the World Conservation Union. This study provides information on the species’ occurrence and distribution along the central Chilean coast from January 2000 to March 2001. Monthly land‐based surveys were performed within the study area, which was divided by the Maule River outlet, with the northern area more influenced by an estuarine system than the southern one. Chilean dolphins were sighted in 83% of surveys. The relative abundance was significantly higher in the northern than the southern area (13.6 dolphins/h versus 3.5 dolphins/ h). Three behaviour categories were recorded (feeding, socialising, and travelling) in both areas, however, these were more frequently observed in the northern area. We suggest that the area located north of Maule River is the preferred zone for Chilean dolphins within the study area. This study shows a year‐round occurrence of Chilean dolphin in the study area which is possibly a critical habitat for this species. Further research focused on population structure assessment and residence patterns of the species in the study area is required.

Survival of Escherichia coli in toroi: A traditional Māori food - L. Dixon; A. Donnison; C. Harfoot; I. R. Mcdonald (New Zealand Journal of Marine and Freshwater Research, 2007)
New Zealand lowland streams and rivers often contain elevated levels of faecal microorganisms, including disease‐causing species and the indicator bacterium Escherichia coli . Filter‐feeding shellfish can accumulate microbial contaminants particularly after extensive rainfall. Toroi is a traditional Maori food prepared from watercress or sow thistle (puha) and shellfish, often sourced from the wild. The mixture is refrigerated in screw‐cappedjars and usually eaten within 2 months. In this study, 10 batches of toroi were prepared from boiled watercress or puha that was mixed with chopped uncooked green‐lipped mussels that were purchased from retail outlets. Portions of each toroi batch were experimentally contaminated with E. coli that was added at two initial concentrations, 0.72 E. coli g ‐1 and 604 E. coli g ‐1 . There was only an occasional detection of E. coli , in very low numbers, from uncontaminated toroi. In contaminated toroi, E. coli declined at similar slow rates at both levels of contamination. This slow rate of decline demonstrates that refrigerated storage should not be relied on as a protective mechanism against a risk of illness. Care should be taken to ensure the shellfish used in toroi are collected from sites that are free from faecal contamination.

First record of the Australian ascidian Eudistoma elongatum in northern New Zealand - Peter J. Smith; Mike Page; Sean J. Handley; S. Margaret McVeagh; Merrick Ekins (New Zealand Journal of Marine and Freshwater Research, 2007)
A colonial ascidian was first reported by marine farmers in Houhora Harbour, Northland, New Zealand in early 2005 and subsequently found on oyster racks in Parengarenga Harbour and the Bay of Islands. The Northland ascidian was identified with a combination of morphological characters and DNA cytochrome c oxidase I (COI) sequence data, as Eudistoma elongatum , a species native to Australia, where it is found from northern New South Wales to Northern Queensland, and distinguished from Eudistoma circumvallatum , the only reported species in this genus from New Zealand. Ascidian larvae are weak dispersers and long distance dispersal of E. elongatum is likely to be enhanced by vectors such as oyster barges and/or movement of cultured oysters. In its native range, E. elongatum is restricted to areas with a minimum winter sea temperature of 16°C. Assuming similar biological limitations apply in New Zealand, the spread of E. elongatum might be restricted to northern New Zealand (north of latitude 37°S).

Stable isotope analysis identifies morphologically indistinguishable caddisflies - Michael J. Winterbourn (New Zealand Journal of Marine and Freshwater Research, 2007)
Stable nitrogen isotope values (δ 15 N) were used to identify the morphologically indistinguishable adult females of Olinga feredayi and O.jeanae (Trichoptera: Conoesucidae), captured in Malaise traps at Cass, inland Canterbury, New Zealand. In the study area, larvae and pupae of the two species were abundant in two different streams and had distinct δ 15 N values, presumably reflecting differences in the stable nitrogen ratios of organic materials assimilated by larvae. In contrast to δ 15 N, stable carbon isotope values (δ 13 C) were more variable and overlapped in the two species. Trapped adult females formed two discrete groups with δ 15 N signatures that corresponded to those of larvae and pupae in the two streams and with those of adult males that can be identified using wing and genitalic characters. The successful identification of otherwise indistinguishable females depended on their larvae having habitat‐specific isotopic signatures that were carried through into the adult stage. Successful identification will not always be possible, but where it is, otherwise unavailable information on the distribution, abundance and dispersal of the adults of aquatic insects can be obtained.

DNA probes, targeting large sub‐unit rRNA, for the rapid identification of the paralytic shellfish poison producing dinoflagellate, Gymnodinium catenatum - Lesley Rhodes; Kirsty Smith; Miguel De Salas (New Zealand Journal of Marine and Freshwater Research, 2007)
The dinoflagellate Gymnodinium catenatum was first observed in New Zealand at Manukau Harbour on the west coast of the North Island in May 2000. At that time, a strong correlation was evident between the micro‐algal bloom and the occurrence of paralytic shellfish toxins (PSP) in shellfish. This paper describes the design and testing of oligonucletide probes targeting the large sub‐unit (LSU) ribosomal RNA (rRNA) of G. catenatum . The probes were developed in fluorescent in situ hybridisation (FISH) and sandwich hybridisation assay (SHA) format to rapidly differentiate the target PSP producer from non‐toxic look‐alike dinoflagellates. Specificity was affirmed by testing the probes against dinoflagellate and flagellate isolates.

Editorial advisory board (New Zealand Journal of Marine and Freshwater Research, 2007)

Dusky dolphin (Lagenorhynchus obscurus) feeding tactics and multi‐species associations - Robin L. Vaughn; Deborah E. Shelton; Lori L. Timm; Leslie A. Watson; Bernd Würsig (New Zealand Journal of Marine and Freshwater Research, 2007)
In this study, monthly changes in dusky dolphin (Lagenorhynchus obscurus) feeding tactics and multi‐species associations in Admiralty Bay and Current Basin, New Zealand were described from August to November 2005 and from May through August 2006. Concurrent changes in dusky dolphin abundance, prey characteristics, and locations of feeding bouts were examined. Data were collected during systematic surveys and focal follows of dolphin groups. During 335 dolphin feeding bouts (52 observed underwater), data were recorded on number of associated fur seal (Arctocephalus forsteri) , seabirds, and sharks; dolphin behaviour; prey ball parameters; and locations. Dolphin feeding tactics, multi‐species associations, and locations of feeding bouts were different from May through July than from August to November. From May through July, dolphins fed on mobile prey at depth; from August to November, they herded small schools of fish (including pilchard Sardinops neopilchardus) to the surface. Primarily shearwaters (Puffinus spp.) fed with dolphins from May through July; shearwaters, gannet (Morus serrator) , gulls (Larus spp.), and fur seal frequently fed with dolphins from August to November. These intra‐annual differences suggest that changes in prey species or behaviour influence dolphin feeding tactics, and influence which species benefit from feeding with dolphins.

Tolerance and behaviour of the mysid shrimp Tenagomysis novae‐zealandiae to low dissolved oxygen - Gregory Larkin; Gerard P. Closs; Barrie Peake (New Zealand Journal of Marine and Freshwater Research, 2007)
Estuarine hypoxia ( 2 /litre) caused by eutrophication has been linked to mass mortality of fish and Crustacea. However, there is little information on the hypoxia tolerance of New Zealand's estuarine mysid shrimps and/or if these species exhibit behavioural and physiological responses to low dissolved oxygen. Laboratory experiments demonstrated the native mysid shrimp Tenagomysis novae‐zealandiae was tolerant of dissolved oxygen levels of 4.0 mg O 2 /litre and 1.5 mg O 2 /litre, but very sensitive to levels 2 /litre. Mortality occurred within 22 min when dissolved oxygen levels decreased to 0.5 mg O 2 / litre, although the 7 h LC 50 value for T. novae‐zealandiae was calculated to be 1.11 mg O 2 /litre. There was a clear relationship between T. novae‐zealandiae activity and decreasing dissolved oxygen levels. Reduced activity appears to be a strategy of T. novae‐zealandiae to tolerate moderate hypoxia (4.0 and 1.5 mg O 2 /litre). However, this behaviour was unsuccessful at 0.5 mg O 2 /litre, as all test organisms demonstrated erratic behaviour and escape responses immediately before loss of equilibrium and mortality.

Persistence of a significant population of rare Canterbury mudfish ( Neochanna burrowsius ) in a hydrologically isolated catchment - Jon S. Harding; David A. Norton; Angus R. McIntosh (New Zealand Journal of Marine and Freshwater Research, 2007)
Canterbury mudfish ( Neochanna burrowsius ) are endemic to a small region of Canterbury, South Island, New Zealand and classified as nationally endangered. We reviewed data from the New Zealand Freshwater Fish Database and trapped fish in July 2006, and January and February 2007 in the Waianiwaniwa Valley, Canterbury to determine the importance of this catchment for mudfish conservation. Mudfish were found in 19 of the 28 sites sampled. Waianiwaniwa Valley sites accounted for 47% of all Canterbury mudfish database records of mean catch per unit effort (CPUE) ≥6 fish. The population comprised young recruits ( 120mm TL) indicating a healthy population. Drying of the lower mainstem, and low dissolved oxygen levels in summer create a unique catchment free of larger predatory fish and with reduced competition from other fish species. We estimated that mudfish occur in at least 24.3 km of the Waianiwaniwa River, making this catchment the most important refuge known for the conservation of this species.

Distribution, substrate preference and habitat enhancement of the isopod Austridotea lacustris in Tomahawk Lagoon, Otago, New Zealand - Celine M. Dufour; Nikita M. Engels; Carolyn W. Burns (New Zealand Journal of Marine and Freshwater Research, 2007)
Aquatic isopods are cryptic, semibenthic components of food webs in coastal water bodies in southern New Zealand. The distribution and abundance of endemic Austridotea lacustris in a modified, urban coastal lagoon were related to selected environmental and habitat variables in field studies and laboratory experiments. Isopods were four times more abundant on lumps of roading conglomerate used in shoreline consolidation than on bricks and natural rocks. Isopod densities were unrelated to the size of the substrate units or their development of biofilm, a major food source for isopods. In experiments to test settlement behaviour with concrete and wood substrates of different structural complexity (with and without holes), isopods showed clear preferences for wood over concrete substrates, and for more complex (more holes per unit area) than less complex (few, or no holes) wood substrates. By increasing the habitat complexity in coastal water bodies, it might be possible to restore and increase populations of aquatic isopods.

Density‐dependent life history differences in a stream mayfly ( Deleatidium ) inhabiting permanent and intermittent stream reaches - C. T. Robinson; T. Buser (New Zealand Journal of Marine and Freshwater Research, 2007)
A life‐history response by the mayfly Deleatidium (Ephemeroptera: Leptophlebiidae) from a permanent‐flowing and an intermittent‐flowing reach of the Selwyn River, New Zealand, to falling water conditions was examined using field populations and laboratory experiments in January 2006. Field populations had similar densities under flowing water conditions, but size distributions were skewed towards larger larvae in the intermittent reach relative to the permanent reach. Under field conditions of falling water at the intermittent reach, more larvae were caught in the drift during the day and more adults at dusk at the intermittent than at the permanent reach. A desiccation study in the laboratory showed that larvae survived up to 3 days under moist conditions, whereas larvae died within 3 h under dry conditions. Another laboratory experiment revealed that both populations increased emergence under falling water in the high density treatment but not in the ambient density treatment. We conclude that a density increase caused by falling water cues late instar larvae to hasten emergence, an adaptive trait that may reduce population mortality from stream drying.

Trout's Larder: a guide to trout food in New Zealand streams. By DuncanGray and JensZollhoefer. Published in 2006 by Reed Publishing (NZ) Ltd, 39 Rawene Rd, Birkenhead, Auckland 10, New Zealand (www.reed.co.nz). 145 p., softcover. ISBN 10:0–7900–1068–2. Price nz$25.00. - Russell G. Death (New Zealand Journal of Marine and Freshwater Research, 2007)

Fluorescent in situ hybridisation assay as a species‐specific identifier of the northern Pacific seastar, Asterias amurensis - Douglas Mountfort; Lesley Rhodes; Judy Broom; Melissa Gladstone; John Tyrrell (New Zealand Journal of Marine and Freshwater Research, 2007)
A fluorescent in situ hybridisation assay has been developed to detect a high profile marine pest in ships’ ballast water, namely the northern Pacific seastar, Asterias amurensis . This organism has not been detected in New Zealand waters, but is seen as a high risk to marine values, including economic resources, should it become established. The fluorescein‐labelled species‐specific probe construct, coded AM2F, scored positive against A. amurensis larvae. The probe was tested for cross‐reactivity against larvae of the starfish Patiriella mortenseni, Coscinasterias muricata , and Sclerasterias mollis . The signal given by the probe against these species was either absent or extremely weak, indicating minimal or no cross‐reactivity The assay detects at the organism level and, because the method involves microscopy, it has potential for enumerating detected species. Additionally, by meeting several criteria for viability assessment (i.e., degree of body wall and organelle integrity as well as fluorescence), the assay can provide indicative counts of viable larvae.

Consequences of base modification in hummocks of the barnacle Austromegabalanus psittacus - Daniel A. López; Boris A. López; Ignacia C. Burgos; Sergio E. Arriagada; María L. González (New Zealand Journal of Marine and Freshwater Research, 2007)
When the barnacle Austromegabalanus psittacus grows in hummocks, the normal structure of the base attached to the substrate, typical of individuals growing in isolation, is modified. In studies undertaken in Metri Bay, southern Chile, cohorts of settled individuals growing in isolation and in groups were evaluated over a period of 14 months, establishing carino‐rostral length as a density‐independent measure of age. One month and six months after larval settlement, size skewness was measured under both growth regimes. Experiments were carried out at two settlement coverages on wooden panels, and growth and mortality were determined. At the same time, shell weight and fecundity of barnacles with a normal and a modified base were evaluated. In monospecific hummocks, the caloric value of tissue was compared between individuals of different sizes, base‐types, and positions within the hummock. No differences were detected in the growth, reproduction and mortality of individuals growing in isolation (normal base) and those growing in groups (modified base). Growth and size skewness were density‐independent during the first 6 months after larval settlement. Fecundity did not vary between individuals of the same size growing in isolation or growing in groups. There were no energetic differences between individuals that grew in isolation with a normal base and those that grew in hummocks with a modified base, or between individuals occupying a central position and those located on the periphery of the hummock. These results suggest that modification of the base in individuals growing at high densities reduces density‐dependent effects, resulting from intraspecific competition for food and substrate. Thus, to interpret intraspecific interactions in barnacles, biological characteristics, such as the capacity to modify base‐types in response to species density must be considered.

Nutrient limitation of periphyton growth in tributaries and the mainstem of a central North Island river, New Zealand - Russell G. Death; Fiona Death; Olivier M. N. Ausseil (New Zealand Journal of Marine and Freshwater Research, 2007)
The management of nutrient inputs into New Zealand waterways is a key focus for environmental agencies, but few North Island studies have examined whether nitrates, phosphates or a combination of nutrients limit periphyton proliferations. The underlying volcanic geology that the Rangitikei River, a large central North Island river, drains would suggest nitrogen (N) as a likely limiting nutrient for periphyton growth. However, examination of nutrient ratios in water samples indicated N‐limitation consistently at only 7 of 11 sites sampled on the mainstem and tributaries of the Rangitikei River. The actual effect of nutrient limitation on periphyton growth was investigated at those same sites using in situ nutrient diffusing substrates. Nutrient limitation was also examined upstream and downstream of sewage discharges from the townships of Taihape, Hunterville, and Bulls. The nutrient diffusing substrates indicated N was the limiting nutrient for periphyton growth at most sites in the mainstem and several tributaries of the Rangitikei River. Sewage discharges at both Taihape and Bulls seemed to alter the nutrient balance in the receiving waterways to the extent that the nutrient diffusing substrates did not indicate any nutrient limitation.

Survival strategies in Polysiphonia adamsiae and P. strictissima (Rhodophyta, Rhodomelaceae) subjected to sediment deposition and grazing pressure - Junxue Mei; David R. Schiel (New Zealand Journal of Marine and Freshwater Research, 2007)
Adaptive strategies of Polysiphonia adamsiae and P. strictissima living in conditions subject to sand deposition and amphipod grazing were investigated by in situ field observations and experimental culture in southern New Zealand between September 2001 and July 2003. The findings from this study showed that for both species, branches regenerated from prostrate axes and fragments grew 7 to 10 times faster than sporelings under the same culture conditions. Also, prostrate axes exhibited extensive creeping growth and produced dense upright branches. In contrast, sporelings exclusively grew upright until they reached c. 1–2 cm. These findings indicate that vegetative propagules have a much higher probability of forming algal turf than sporelings. In addition, prostrate axes survived darkness longer than sporelings, implying that algal thalli might be protected from amphipod grazing by sediments. This study shows that vegetative modes of reproduction predominated over sporic modes in both species. Vegetative reproduction might be advantageous for thalli to survive amphipod grazing under turf‐trapped sand.

A new species of Trileptium (Nematoda, Thoracostomopsidae) from a sandy beach in southeastern Australia, with a key to species and observations on geographical distribution - Warwick L. Nicholas (New Zealand Journal of Marine and Freshwater Research, 2007)
Thoracostomopsidae are common predatory marine nematodes found in littoral and sub‐littoral sands. The buccal cavity is characterised by a mandibular complex and onchia (teeth) forming grasping jaws. Three constituent subfamilies and genera are distinguished by variations in the development of these structures. Of the three subfamilies, Thoracostominae have been found in sub‐littoral habitats and have not been reported from Australia. A number of species from several genera of Enoplolaiminae have previously been recorded from southeastern Australian beaches. In this paper, Trileptium australis n. sp. belonging to the third subfamily, Trileptiinae, is described from one of these beaches. In this genus, weakly developed mandibles and one, or three, well developed onchia are situated closer to the mouth opening than in Enoplolaiminae, and the lips have a lower profile. Important specific diagnostic characters of Trileptium australis n. sp. are the possession of three onchia, absence of cuticular annulation, presence of a pre‐cloacal supplementary organ, thin strongly curved spicules with mid‐ventral pegs and a gubernaculum that loops over the spicules. A dichotomous key for the 11 described species, based on male characters, is provided. The geographical distribution of all the described species is reviewed. One species, T. subterraneum has a very wide geographical distribution, but other species appear to be restricted to one sea or ocean.

Age at first increment formation and validation of daily growth increments in golden perch (Macquaria ambigua: Percichthyidae) otoliths - Paul Brown; Ian Wooden (New Zealand Journal of Marine and Freshwater Research, 2007)
The micro‐increments in otoliths from a series of golden perch (Macquaria ambigua) larvae of up to 15 days known age (n = 124, total length (TL) 4.14 to 10.0 mm) were examined and counted to establish the age at formation of the first increment, and periodicity of formation of subsequent increments. The regression of true age on increment count (true age = 3.54 +1.36 × increment count) was significant (r 2 = 0.78, P 0.001) and the slope of the overall regression (1.36 day –1 ) was not significantly different to 1 (t = 0.09, P = 0.05). First increment formation occurred from day 3 in some larvae, and was completed by day 13 in all larvae. A median estimate for age at first‐increment deposition was 6.0 days, when 50% of the daily sample (n = 10 fish) had at least one increment. However, solving the regression for age when increment number equaled 1.0 provided an estimate of mean age at first‐increment deposition of 4.9 days. Our study validated daily growth increment deposition for golden perch larvae over the first 15 days of development and cautions that age at first‐increment formation varied within a single cohort of larvae by 10 days (i.e., youngest larvae 3 days, oldest larvae 13 days old).

A hydrodynamic model of Chatham Rise, New Zealand - Mark G. Hadfield; Graham J. Rickard; Michael J. Uddstrom (New Zealand Journal of Marine and Freshwater Research, 2007)
A three‐dimensional hydrodynamic ocean model, the Regional Ocean Modelling System (ROMS), was applied to a region encompassing the Chatham Rise, New Zealand and forced by surface fluxes from an atmospheric reanalysis data set. The model outputs fields were validated against a number of observation‐based data sets, including the CSIRO Atlas of Regional Seas 2000 (CARS 2000) climatology of sub‐surface temperature and salinity, a sea surface temperature (SST) climatology from the NIWA SST Archive (NSA), and sea surface height (SSH) from the Archiving, Validation and Interpretation of Satellite data in Oceanography (AVISO) Mapped Sea Level Anomalies (MSLA) data set. The model reproduced the flow around Chatham Rise well and had a realistic seasonal cycle in the upper ocean. Its biggest deficiency was that the Wairarapa Eddy was too steady and pushed warm water too far south towards the head of Hikurangi Trough. This exercise confirms the need to validate a model against multiple data sets and shows the value of SST data for revealing underlying oceanographic features.

Two‐step linear regression based on spectral absorption to detect cyanobacteria in fresh water - Asha U. M. Lokuhewage; Satoru Toyooka (New Zealand Journal of Marine and Freshwater Research, 2007)
A simple spectral absorption method based on two‐step linear regression was used to identify and estimate the quantity of cyanobacteria (Cyanophyceae) among other phytoplankton species in mixed freshwater populations. We focused on four major algal groups, the Cyanophyceae, Chloro‐phyceae, Bacillariophyceae, and Dinophyceae, as typical representatives in the fresh waters of the kanto region of Japan, and dissolved organic carbon (DOC). In the first step, simple linear regression analysis was applied to determine the relationship between spectral absorption characteristics and concentration for each pure sample which contained only one of the four algal groups or DOC. In the second step, the resultant characteristics represented by gradient vectors were used to estimate concentrations of the four algal species and DOC in mixed samples by multiple linear regression analysis. We used the method described here to estimate the quantity of cyanobacteria among algal communities cultured in the laboratory under four different light conditions and in field samples. The method accounted for variations in the spectral characteristics of cyanobacteria owing to different light conditions, which were caused by changes in the ratio of phycocyanin to chlorophyll a . Variations in spectral characteristics of cyanobacteria under different light conditions were assessed geometrically using a vector subspace method based on principal component analysis (PCA). The vector subspace method allowed a detailed study of spectral variation of cyanobacteria recognition under different light conditions in 3‐D space.

A possible false negative: Lack of evidence for trout predation on a remnant population of the endangered Macquarie perch, Macquaria australasica , in Cotter Reservoir, Australia - Brendan Ebner; Ben Broadhurst; Mark Lintermans; Mark Jekabsons (New Zealand Journal of Marine and Freshwater Research, 2007)
To investigate possible predation on a remnant population of the endangered Macquaria australasica in Cotter Reservoir, ACT, Australia, stomach content analysis was conducted on 63 rainbow trout Oncorhynchus mykiss and 24 brown trout Salmo trutta . Both predators were found to be piscivorous, with the frequency of piscivory generally increasing with body size. Goldfish Carassius auratus were the only fish species identified in stomach contents. That gape‐limitan on prevented trout from feeding on juvenile M. australasica was eliminated as a possibility based on: (1) the body depth of prey and the mouth‐size of predators; and (2) evidence that another species of similar dimensions was ingested by trout. Whether or not trout predation on M. australasica is an important process in Cotter Reservoir remains to be clarified. Juvenile M. austalasica do not reside in the parts of the reservoir from which most trout were actually sampled in the current study. Therefore, it is proposed that the lack of evidence for predation on M. australasica is potentially a false‐negative result.

First record of Centrophorus harrissoni from New Zealand, with observations on squamation in centrophoridae (squaliformes) - Clintoni A. J. Duffy (New Zealand Journal of Marine and Freshwater Research, 2007)
Three specimens of Centrophorus from the southern Norfolk Ridge, three Kings Ridge, and Kermadec Ridge are provisionally identified as C. harrissoni , extending the species’ known range east to 178°52.1 ' W. Although apparently rare, C. harrissoni is widely distributed in southern Australian waters and the southwest Pacific between 17°S and 43°S, occurring on continental and insular slopes and oceanic ridges from 450 to 1048 m depth. Differences in dental morphology between juvenile male and female type specimens, a juvenile male from southern Norfolk Ridge and an adult male from the Kermadec Ridge were tentatively attributed to sexual dimorphism. However, additional specimens and research are required to confirm the identity of nominal C. harrissoni from Norfolk Ridge and northern New Zealand. Eight Centrophorus spp., including C. harrissoni , and three Deania spp. were found to differ from C. squamosus in having an area of transverse dermal folds on the ventral surface of the head between the gills. in C. harrissoni and Deania spp. these are naked except for a row of denticles along the top of each fold. in C. harrissoni these denticles are minute and thorn‐like, whereas in Deania spp. they have tridentate crowns on short, straight pedicles.

Fish swimming speed variability at constant flow: Galaxias maculatus - David R. Plew; Vladimir I. Nikora; Scott T. Larned; Julian R. E. Sykes; Glenn G. Cooper (New Zealand Journal of Marine and Freshwater Research, 2007)
Digital videography was used to study the swimming performance of the adult fish Galaxias maculatus in a flume at fixed flows. Instantaneous fish swimming velocities varied about the mean flume velocity and these variations in swimming speed were found to increase as velocity in the flume increased. Standard deviations in swimming velocity measured in the longitudinal direction increased from SD 0.183 m s –1 at U 0 = 0.40 m s –1 , SD 0.191 at U 0 = 0.48 m s –1 to SD 0.237 m s –1 at U 0 = 0.60 m s –1 . Increases in standard deviations were also seen in cross‐stream and vertical swimming velocities. Similarly, variability in acceleration increased as flume velocity was increased with SD 1.850 m s –2 at U 0 = 0.40 m s ‐1 , SD 2.492 m s –2 at U 0 = 0.48 m s –1 , and SD 3.125 m s –2 at U 0 = 0.60 m s –1 recorded for the longitudinal acceleration component. Maximum swimming velocities of 2.05 m s –1 and accelerations of 25.4 m s –2 were recorded.

New Zealand sea lion, Phocarctos hookeri , pup production—1995 to 2006 - B. L. Chilvers; I. S. Wilkinson; S. Childerhouse (New Zealand Journal of Marine and Freshwater Research, 2007)
The New Zealand sea lion (NZ sea lion), Phocarctos hookeri , is New Zealand's only endemic pinniped. Classified as vulnerable, it is one of the world's rarest pinnipeds. During the 1994/95 austral summer, a long‐term population‐monitoring programme of the Auckland Island colonies was initiated using standard procedures to estimate annual pup production. This paper reports the pup production estimates for the known NZ sea lion population over the last 12 years (1994/95 to 2005/06), and the variation in pup production estimates for the Auckland Islands. sixty‐four percent of the pup production for the entire NZ sea lion population occurred at Dundas Island, followed by Enderby Island (19%), and Figure of Eight Island (3%). These three sites are all at the Auckland Islands, making this area the primary breeding site for this species with 86% of all pup production occurring here. The remaining 14% were born at Campbell Island, with otago Peninsula representing

Avoidance of native versus non‐native predator odours by migrating whitebait and juveniles of the common galaxiid, galaxias maculatus - Felicity McLean; Nicole C. Barbee; Stephen E. Swearer (New Zealand Journal of Marine and Freshwater Research, 2007)
Avoidance of predator odours by migrating Galaxias maculatus was studied in the laboratory using a two‐chamber choice tank. The odours of a native predator (short‐finned eel, Anguilla australis) and an introduced predator (rainbow trout, Oncorhynchus mykiss) were tested on both whitebait (i.e., new recruits) and juveniles. Both whitebait and juveniles exhibited avoidance behaviour when exposed to eel odours. There was no avoidance response from either the whitebait or juvenile G. maculatus when exposed to trout odours, which could suggest differences in the ability of G. maculatus to detect native and introduced predators. Observed negative effects of introduced predators on native species may be owing in part to the absence of innate avoidance behaviour in native prey species.

Trophic interactions promote dominance by cyanobacteria (Anabaena spp.) in the pelagic zone of lower Karori reservoir, Wellington, New Zealand - K. F. Smith; P. J. Lester (New Zealand Journal of Marine and Freshwater Research, 2007)
Cyanobacterial blooms have occurred in the Lower Karori Reservoir (Wellington, New Zealand) since 2000, resulting in reduced water quality and potential health risks. This study examined the factors that contribute to the cyanobacterial blooms in the reservoir (October 2003 to July 2004). In particular, it examined how thermal stratification influences the chemical dynamics in the reservoir, and the potential cascading effect of zooplanktivorous perch (Perca fluviatilis) in promoting high phytoplankton biomass. Thermal stratification, coupled with increased water column stability occurred from October to March. Oxygen levels were reduced in the hypolimnion during stratification. Nutrient concentrations declined during stratification and became elevated after the collapse of the bloom in February 2004. Concentrations of Anabaena lemmermannii increased with the onset of thermal stratification. Zooplankton abundance peaked during stratification and consisted mainly of rotifers. The perch caught during this study were typically small‐sized individuals, which had consumed mostly large‐sized zooplankton. The development of cyanobacterial blooms in the Lower Karori Reservoir is probably owing to a combination of factors including low nitrogen concentrations that favour nitrogen‐fixing cyanobacteria and the ability of cyanobacteria to adjust their buoyancy and maintain their position in the water column during thermal stratification. Predation by perch probably maintains large zooplankton species at low densities and consequently reduces grazing pressure on phytoplankton populations.

Predation by rainbow trout (Oncorhynchus mykiss) on a Western Australian icon: Marron (Cherax cainii) - Michelle Y. Tay; Alan J. Lymbery; Stephen J. Beatty; David L. Morgan (New Zealand Journal of Marine and Freshwater Research, 2007)
Considerable numbers of rainbow trout (Oncorhynchus mykiss) are captively produced then stocked into many wild aquatic systems in Western Australia despite a lack of understanding of their impact on the highly endemic native fish and freshwater crayfish of the region. The diet of an introduced, yet self‐sustaining population of O. mykiss was examined at Churchman Brook Reservoir in the Canning River Catchment, Western Australia, between September and November 2004. The large endemic freshwater crayfish marron (Cherax cainii) , which supports an iconic recreational fishery in Western Australia, comprised 61% by volume of all O. mykiss stomachs examined. The contribution made by C. cainii to the assimilated biomass of O. mykiss was confirmed by stable isotope analyses, which revealed that it dominated the assimilated diet of larger O. mykiss . The substantial contribution of C. cainii to the diet of wild O. mykiss suggests that, at least in habitat limited water bodies, it is likely to have a considerable predatory impact on C. cainii populations and may compromise some elements of this iconic recreational fishery.

Invasive marine red alga introduced to New Zealand waters: First record of Grateloupia turuturu (Halymeniaceae, Rhodophyta) - R. D'Archino; W. A. Nelson; G. C. Zuccarello (New Zealand Journal of Marine and Freshwater Research, 2007)
The red alga Grateloupia turuturu is recorded from New Zealand waters for the first time. This species, native to Japan, is considered to be invasive in western Europe, North America, and Tasmania. The occurrence of G. turuturu is confirmed by molecular analysis of chloroplast‐encoded rbc L and mitochondrial cox 2–3 spacer sequences as well as the vegetative and reproductive anatomy of both tetrasporophyte and gametophyte specimens.

Growth and productivity of intertidal Zostera capricorni in New Zealand estuaries - S. J. Turner (New Zealand Journal of Marine and Freshwater Research, 2007)
In situ leaf and rhizome growth and productivity rates were determined for intertidal populations of Zostera capricorni in three New Zealand estuaries on four occasions in summer and winter 2000 and 2001. Leaf growth and productivity, leaf plastochrone interval, leaf life‐spans and turnover rates were found to vary depending on site, bed position, season, and year. Absolute leaf growth (2.1±0.8mm leaf ‐1 day ‐1 ) and productivity (0.4+0.2 mg shooir ‐1 day ‐1 ) were generally lowest, relative growth (0.2±0.6mm leaf ‐1 day ‐1 ) and productivity (0.4±0.4 mg shoot ‐1 day ‐1 ) highest, and the leaf and shoot plastochrone intervals shorter at the site exposed to greater desiccation stress and photoinhibitory high irradiances. Rhizome growth rates, the production of new branches and shoots, as well as rhizome and shoot plastochrone intervals were also found to vary depending on site, season, and year. The results indicate that Z. capricorni is able to maintain high productivity and growth rates in intertidal estuarine environments which signify a high degree of environmental stress for marine plants.

A submersible device for measuring drag forces on aquatic plants and other organisms - Fraser M. Callaghan; Glenn G. Cooper; Vladimir I. Nikora; Nicolas Lamouroux; Bernhard Statzner; Pierre Sagnes; John Radford; Emmanuel Malet; Barry J.F. Biggs (New Zealand Journal of Marine and Freshwater Research, 2007)
This paper describes a device, the submersible drag gauge (SDG), that can be used for drag measurements in studies of flow‐biota interactions at low (setup A) and high (setup B) load applications. The device is designed so that solely drag forces acting on a test object in a boundary layer now are measured. The SDG can measure drag on organism(s), such as macrophtyes, crayfish or mussels, as well as a combination of such organisms and sediments assembled in a variety of arrangements in both laboratory and field conditions. Laboratory calibrations over the range of 0 to 4 N showed that setup A registered forces as low as 0.02 N, whereas setup B often did not register forces up to c. 0.15 N. The relative standard error of drag measurements was 0.2 N (setup A) or 1 N (setup B). Using a rigid cylinder, and natural and artificial (plastic) Egeria densa as examples, showed how the SDG can serve in studies of flow‐biota interactions such as drag‐velocity relations, assessments of drag coefficients, or the frequency spectrum of macrophyte drag.

Longitudinal changes in biota along four New Zealand streams: Declines and improvements in stream health related to land use - Dev K. Niyogi; Mark Koren; Chris J. Arbuckle; Colin R. Townsend (New Zealand Journal of Marine and Freshwater Research, 2007)
We studied four streams in southern New Zealand in 2002 to document downstream changes in water quality, habitat, and stream biota in relation to land use. Two streams were in catchments that had increasing intensity of agricultural development downstream from relatively pristine headwaters. A third stream had the most intense land use in the headwaters and a riparian corridor of regenerating native forest along its middle reaches. A fourth stream had low intensity pasturing in its lower reaches, but also downstream increases in sedimentation from natural and historic mining sources. Four to six sites were sampled along each stream. Pastoral land cover in catchments was positively related to nutrient concentrations and fine sediment cover in the streams. At the most agricultural sites, dissolved inorganic nitrogen reached concentrations of 2 mg/litre, and fine sediment covered 33% of the stream bottom. Several biotic indices for invertebrates, including the Macroinvertebrate Community Index (MCI), were lower at the agricultural sites, which had MCI scores around 100. The indices were negatively related to fine sediment cover. The site with the intact riparian zone had declines in sedimentation downstream, which were paralleled by increases in invertebrate richness and biotic indices. Our findings support the notion that the restoration of riparian zones can improve stream habitat and invertebrate health.

Dissolved organic carbon in New Zealand peatlands - Tim R. Moore; Beverley R. Clarkson (New Zealand Journal of Marine and Freshwater Research, 2007)
We determined the concentration of dissolved organic carbon (DOC) and the specific ultraviolet absorbance (SUVA) of 193 samples of water collected from groundwater, porewater, drainage ditches, and streams at peatlands in New Zealand. There was a wide range in DOC concentration (from 7 to 184 mg litre –1 ), with the smallest concentrations in peatlands where there appeared to be large amounts of iron. Concentrations were large (generally >50 mg litre –1 ) in ombrotrophic (rain‐fed) peatlands and reached the highest values (averaging 81 to 129 mg litre –1 ) in water collected from the Torehape peatland (Waikato region), which is undergoing drainage and harvesting for peat and post‐harvest restoration. These high DOC concentrations suggest that New Zealand peatlands export 10 to 50 g DOC m –2 yr –1 , a significant part of the overall carbon budget of peatlands. Most SUVA measurements ranged from 1.5 to 3.5 litre/mg DOC ‐1 /m –1 ) and suggest that the DOC contains 12 to 25% aromatics.

Tides in two constricted New Zealand lagoons - N. Albrecht; R. Vennell (New Zealand Journal of Marine and Freshwater Research, 2007)
We used a non‐linear model, which incorporates tidal choking coupled to the geometry of the lagoon and its channel to interpret data collected from two constricted New Zealand lagoons, Hooper's Inlet and Papanui Inlet, Otago Peninsula, south eastern New Zealand. The model reproduced many of the observed features, although it yielded better results for Papanui Inlet which had weaker tidal choking. Tide data from both lagoons showed varying degrees of distortion owing to the constricted channels. Both lagoons were characterised by a reduced amplitude and a lag in the timing of high and low tides compared to the open sea reference point at Taiaroa Head, with an irregular ebb‐flood duration. Although Taiaroa Head had a mean tidal range of 1.49 m and its high and low tides occurred first, Papanui Inlet had a tidal range of 1.15m and lagged Taiaroa Head by 60 min, whereas adjacent Hooper's Inlet had the smallest range of 0.43m and a lag of 103 min. All sites had a clear spring‐neap envelope, with Hooper's Inlet lagging behind Taiaroa Head and Papanui Inlet by about 1 day. The reduced amplitude and the lag in timing of high and low tides compared to the forcing open sea tide are caused by tidal choking owing to the narrow, shallow channels connecting the lagoons to the open sea.

Effects of flume characteristics on the assessment of drag on flexible macrophytes and a rigid cylinder - Glenn G. Cooper; Fraser M. CallaGhan; Vladimir I. Nikora; Nicolas Lamouroux; Bernhard Statzner; Pierre Sagnes (New Zealand Journal of Marine and Freshwater Research, 2007)
Previous research, using rigid objects, showed that the magnitude of mean drag on submerged bodies can be influenced by the blockage ratio (ratio of the frontal projection area of an object to the wetted flume cross‐sectional area). In addition, drag measurements, under similar flow conditions, are likely to be affected by other flume characteristics. these factors lead to some uncertainty in drag measurement comparisons between identical objects for a given reference flow velocity. We measured drag on three pairs of replicate objects (two types of flexible artificial macrophyte and a rigid cylinder) in two flumes differing in width (0.25 and 0.75 m). Owing to different flume widths, the blockage ratios differed between the flumes for the macrophytes (c. 7% and c. 22% at intermediate flow rates) and the cylinder (2.5% and 7.5%). For theoretically identical mean cross‐sectional velocities, the between‐flume difference in mean centreline channel velocities across the range of flows used in this study was 6.4%, indicating similar bulk flow conditions for the two flumes. We found no between‐flume differences in drag‐velocity relationships for the cylinder, whereas one macrophyte had a distinctly higher drag in the narrower flume at low approach velocities (c. 0.2 m s –1 ). This difference of drag on the macrophyte likely indicates blockage effects in the narrower flume at low velocities, when plant bending and streamlining was low. At higher approach velocities, between‐flume differences in drag on the macrophytes were minor, except for one type of macrophyte that had a higher drag at the highest velocity in the wider flume (possibly related to plant reconfiguration and fluttering).

Spatial and temporal variation in the fish community of a South Island, New Zealand coastal lake - Giri R. Kattel; Gerard P. Closs (New Zealand Journal of Marine and Freshwater Research, 2007)
Communities in shallow coastal lakes are exposed to frequent environmental variation owing to their proximity to marine environments, and seasonal and daily variation in climate. Consequently, variability in these communities is likely to be considerable. The fish community of Lake Waihola, a shallow coastal South Island/New Zealand lake, was assessed by monthly day and night sampling by push net. A total of eight fish species were collected between January 1998 and January 1999. Common bully (Gobiomorphus cotidianus) comprised 78.92% of the total catch collected over the study period. Highest catches of common bully occurred inlate summer and autumn, mostly at night. Juvenile perch (Perca fluviatilis) were also caught in high numbers for a short period in mid‐summer, also mostly at night. Common smelt (Retropinna retropinna) and inanga (Galaxias maculatus) were collected in low numbers from late winter through to late autumn. Other species collected included shortfin eel (Anguilla australis) , yellow‐eyed mullet (Aldrichetta forsteri) , lamprey (Geotria australis) , and black flounder (Rhombosolea retiaria) . Variation in abundance was attributed to life history and ontogenic shifts in habitat use, and changes in habitat structure related to the development of submerged macrophyte beds during warmer summer periods.

A biotic index for New Zealand's soft‐bottomed streams - John D. Stark; John R. Maxted (New Zealand Journal of Marine and Freshwater Research, 2007)
Versions of the Macroinvertebrate Community Index (MCI) and its semi‐quantitative (SQMCI) and quantitative (QMCI) variants used extensively in New Zealand to assess organic pollution in hard‐bottomed (HB) streams have been developed for assessing the health of soft‐bottomed (SB) streams dominated by fine sediments, woody debris, and macrophytes. Aniterative rank correlation procedure developed in Australia was used to derive tolerance values for 124 macroinvertebrate taxa using a data set of 224 samples from 50 sites in the Auckland region. Deriving SB tolerance values to the nearest 0.1 (range 0.1–10.0) improved index performance and eliminated confusion with the integer tolerance values of the HB indices. The new indices (MCI‐sb and SQMCI‐sb), exhibited a greater range of scores overall and across gradients of forestry, rural, and urban land‐use intensity compared to the MCI and SQMCI when applied to SB streams. Higher scores for reference sites, lower scores for severely degraded sites, and high rank correlations (r s ) with environmental variables, including % developed land in the catchment (r s = ‐0.842), a water quality index (r s = 0.818), and a habitat quality index (r s = 0.648), confirmed the superiority of MCI‐sb for classifying SB sites. Tolerance values for 35 additional taxa were derived using data from six other regions of New Zealand combined with the Auckland data. The interpretation of HB and SB versions of the MCI, SQMCI, and QMCI are the same (i.e., “excellent”: >120 or >6.00, “good”: 100–119 or 5.00–5.99, “fair”: 80–99 or 4.00^.99, “poor”:

Multiple indicators reveal river plume influence on sediments and benthos in a New Zealand coastal embayment - Barrie M. Forrest; Paul A. Gillespie; Chris D. Cornelisen; Karyne M. Rogers (New Zealand Journal of Marine and Freshwater Research, 2007)
Multiple physico‐chemical and biological indicators were used to delineate the spatial influence of the Motueka River plume on coastal surface sediments and associated biota in Tasman Bay, New Zealand. Sediments were primarily muds at nearshore sites on all transects and comprised coarser sediments at the most seaward sites in Tasman Bay. Organic carbon/nitrogen ratios, stable carbon and nitrogen isotope signatures, and certain lipid biomarkers and trace metals provided suitable indicators of terrestrial and riverine influence on subtidal sediments. Analysis of these parameters revealed a discernible catchment influence extending at least 6 km offshore in the river outwelling plume, with a pronounced signature evident at two sampling stations within approximately 2km of the Motueka River mouth. At these two nearshore sites, nickel and chromium from natural upper‐catchment sources were present at concentrations greatly exceeding sediment quality thresholds for probable ecological effects. The infaunal assemblage at these sites comprised low densities of a few opportunistic taxa, with the spatial distribution of organisms strongly correlated with trace metal concentrations. Although a causal relationship with trace metals is possible, other unmeasured influences such as gradients of salinity, depth and physical disturbance could conceivably be the primary drivers of the biological pattern. By contrast with the effects on infauna, analyses of stable carbon and nitrogen isotopes and trace metals in epibenthic shellfish did not reveal any evidence of a direct terrestrial or riverine influence. Overall, the results from this work indicate a relatively localised river plume effect on subtidal sediments and the associated infaunal assemblage. However, because previous work has shown that the river plume can extend tens of kilometres offshore during flood flows, further investigation is required to understand changes in seabed parameters within the context of spatio‐temporal variation in catchment inputs and river plume discharge.

Characterisation of cavortin, the major haemolymph protein of the Pacific oyster (Crassostrea gigas) - Paul D. Scotti; Sally C. Dearing; David R. Greenwood (New Zealand Journal of Marine and Freshwater Research, 2007)
Evidence suggests that members of the oyster genus Crassostrea share a common haemolymphprotein. Cavortin, the major haemolymph protein of the Pacific oyster (Crassostrea gigas) , comprises 174 amino acid residues totalling 19.4 kDa and is rich in histidine and aspartic acid. The protein consists of a single Cu/Zn SOD (superoxide dismutase) derived domain showing homology to each of the three SOD‐like domains of pernin, the related 60 kDa protein from the green‐lipped mussel (Perna canaliculus) . Despite some homology to Cu/Zn SOD sequences we found no compelling evidence that it has retained SOD function. Cavortin has affinity for several divalent cations, particularly iron. Each cavortin monomer is able to bind 8–11 iron ions, but can sequester considerably more iron, presumably by forming spheroid particles. The primary function of cavortin, like pernin, has been altered during the course of evolution, but has yet to be determined unambiguously. A likely role is as a metal ion chaperone.

Habitat use by banded kokopu (Galaxias fasciatus) and giant kokopu (G. argenteus) co‐occurring in streams draining the Hakarimata Range, New Zealand - Cindy F. Baker; Joshua P. Smith (New Zealand Journal of Marine and Freshwater Research, 2007)
Habitat selection by banded kokopu (Galaxias fasciatus) and giant kokopu (G. argenteus) was examined in three first‐ and second‐order restored streams draining the Hakarimata Range, Waikato region, New Zealand. Longitudinal distribution surveys were undertaken recording physical habitat dimensions and cover selection at the location of each banded and giant kokopu. The main habitats used by both species were pools or backwaters, and both species strongly selected debris dams and undercut banks over other types of in‐stream cover. The key features discriminating banded kokopu and giant kokopu habitat were elevation, habitat size, and riparian cover. Banded kokopu were found at higher elevations than giant kokopu, where habitats had smaller dimensions and higher proportions of native bush as riparian cover. Within the study streams, in‐stream debris, in the form of debris dams, was strongly selected as cover by both species and therefore could be an important feature in habitat restoration within the Waikato region, especially in streams where undercut bank cover is scarce.

Do parasites affect burrowing depth and habitat choice of sand hoppers, Talorchestia quoyana (Amphipoda: Talitridae)? - Rohan J.C. Currey; Robert Poulin (New Zealand Journal of Marine and Freshwater Research, 2006)
Talorchestia quoyana is the most abundant sand hopper (Amphipoda: Talitridae) on New Zealand's beaches. These supralittoral detritivores are host to a parasitic mermithid nematode, Thaumamermis zealandica. In other systems, mermithids have been found to manipulate host behaviour to facilitate the continuation of their lifecycle. The aim of the present study was to determine if the burrowing behaviour of T. quoyana showed evidence of manipulation by T. zealandica. Two studies were conducted to assess the spatial and temporal patterns in sand hopper burrowing under field and laboratory conditions. Sand hopper burrowing behaviour showed considerable variation, related to sand hopper length, sand hopper distribution, month of collection, and experimental moisture conditions. The presence of parasites was not a significant factor in determining sand hopper burrowing behaviour, a result contrary to previous laboratory findings for this system. This study illustrates the benefits of combining both field and laboratory experiments to evaluate whether or not parasites alter host behaviour.

Age composition, growth, and reproduction of koi carp (Cyprinus carpio) in the lower Waikato region, New Zealand - Grant W. Tempero; Nicholas Ling; Brendan J. Hicks; Matthew W. Osborne (New Zealand Journal of Marine and Freshwater Research, 2006)
A total of 566 koi carp ( Cyprinus carpio ) from the lower Waikato region were aged from scales and opercular bones, and growth was modelled with the von Bertalanffy growth function. There was no difference in growth rate between male and female carp. Growth of koi carp between zero and 3 years of age was lower than that of common carp in Europe and Australia. However, after 5 years of age the growth of koi carp was higher than that of common carp in Europe, but still below that of carp in Australia. Males rarely lived in excess of 8 years, whereas females lived to 12 years. Mean total fecundity calculated from 44 running‐ripe females was 299000 oocytes (±195600 SD) (range 29800–771000). Relative fecundity ranged from 19300 to 216000 oocytes kg ‐1 total body weight, with a mean of 97 200 (±35 000 SD) oocytes kg ‐1 . Feral koi carp in the Waikato are capable of multiple spawnings within their lifetimes. Within a spawning season, Waikato populations of feral koi carp contained females that spawned once, and females that had the potential to have spawned repeatedly. Female gonadosomatic index (GSI) varied with season and was negatively related to water temperature.

Adventive occurrence in New Zealand of the scale‐worm Paralepidonotus ampulliferus (Annelida: Polychaeta: Polynoidae) - Geoffrey B. Read (New Zealand Journal of Marine and Freshwater Research, 2006)
The distinctive polynoid Paralepidonotus ampulliferus is known to be distributed across the Indian Ocean and the western Pacific Ocean, and is present around much of the Australian coast. It is reported here for New Zealand for the first time, and a description is provided. The scale‐worm has been found subtidally in Whangarei Harbour, and is widespread around the soft‐shores of Waitemata Harbour (Auckland) and nearby Hauraki Gulf inlets, with the earliest record dating from late 1998. Surveys before 2003 in Waitemata Harbour, Whangarei Harbour, and elsewhere around New Zealand had not detected the species. Its presence in New Zealand is evaluated as unlikely to have been achieved without human‐mediated assistance.

Do toxic baits containing sodium fluroacetate (1080) affect fish and invertebrate communities when they fall into streams? - Alastair M. Suren; Paul Lambert (New Zealand Journal of Marine and Freshwater Research, 2006)
Large‐scale control of Australian possums throughout New Zealand uses toxic cereal baits containing 1080 (sodium fluoroacetate). These baits are often aerially applied over rough terrain where ground application is impractical. Many small streams flow in these areas, so 1080 baits can potentially fall into them. The ecological effect of 1080 leaching from baits was assessed on freshwater fish and invertebrate communities in four streams using a BACI experimental design. Four sites were selected in each stream: 10m and 100m below and 10m and 100m above where 1080 baits were placed. All sites were monitored 4 days and 1 day before and after baits were added, respectively. Separate experiments were conducted to assess impacts of 1080 on native fish and invertebrate communities. Baits were added to each stream to achieve bait densities 10 × greater than found after normal control operations. Three species of native fish, longfin eels ( Anguilla dieffenbachii ), koaro ( Galaxias brevipinnis ), and upland bullies (Gobiomorphus breviceps) were placed into separate cages at each site in each stream, and mortality monitored during the experiment. Analysis of water samples collected during the fish experiment showed that 1080 was detected only for 12h, and at low concentrations (c. 0.2 ì g litre ‐1 ), despite the large number of baits placed in each stream. No fish died after addition of 1080 baits, suggesting that all three species were tolerant to dissolved 1080 at concentrations observed in this study. Invertebrate communities were quantified by sampling 10 replicate rocks at each site. Caddisflies (Helicopsyche, Pycnocentrodes, and Pycnocentria), orthoclad midges, and the mayfly Deleatidium dominated the community. 1080 had no detectable effects on the invertebrate community. These results suggest that 1080 leaching from submerged baits in small streams has no demonstrable biological impacts. Based on this finding, the need to maintain buffer zones around large waterways as some councils require is questioned.

Survey of cyanotoxins in New Zealand water bodies between 2001 and 2004 - S.A. Wood; P.T. Holland; D. J. Stirling; L. R. Briggs; J. Sprosen; J. G. Ruck; R. G. Wear (New Zealand Journal of Marine and Freshwater Research, 2006)
Contamination of drinking and recreational water bodies by toxic cyanobacteria is a significant water management issue in many countries. Until recently, knowledge of the occurrence of cyanotoxins and species responsible for cyanotoxin production in New Zealand was limited. In this study a total of 266 water and cyanobacterial mat samples collected from 227 different water bodies between 2001 to 2004 were analysed for cyanotoxins. Enzyme‐linked immunosorbent assays, liquid chromatography mass spectrometry, high performance liquid chromatography, and neuroblastoma assays resulted in the identification of microcystins/nodularins (102 samples from 54 different water bodies), anatoxin‐a (three samples from three different water bodies), and saxitoxins (48 samples from 41 different water bodies). The highest microcystin concentration was 36.5 mg litre ‐1 . The detection of anatoxin‐a is the first definitive report for New Zealand. Only low concentrations of saxitoxins were detected. Results indicate that cyanotoxins are more widespread in New Zealand water bodies than previously reported, in particular when cyanobacterial blooms or benthic cyanobacterial mats are present.

First New Zealand records of three non‐indigenous Zooplankton species: Skistodiaptomus pallidus, Sinodiaptomus valkanovi, and Daphnia dentifera - Ian C. Duggan; John D. Green; David F. Burger (New Zealand Journal of Marine and Freshwater Research, 2006)
We present the first records from New Zealand of three non‐indigenous freshwater Zooplankton species: the Japanese Sinodiaptomus valkanovi, North American Skistodiaptomus pallidus (Copepoda), and Daphnia dentifera (Anomopoda). Owing to their geographic origins, introduction to New Zealand by natural passive dispersal is highly unlikely. Skistodiaptomus pallidus was found in Auckland ponds at two localities, and also among live fish food sold in an aquarium store. As such the aquarium trade is an active vector. Skistodiaptomus pallidus and S. valkanovi are currently restricted in distribution to constructed ponds and, although they have the potential to spread, eradication may still be possible. However, D. dentifera is widespread and eradication is not feasible. Prevention of further Zooplankton invasions will rely on examination of potential introduction vectors, and adoption of effective management strategies for each vector (e.g., the prevention of the sale of live food containing non‐indigenous species from aquarium stores).

An acoustic survey of baleen whales off Great Barrier Island, New Zealand - M. A. McDonald (New Zealand Journal of Marine and Freshwater Research, 2006)
Acoustic recordings of baleen whale calls were analysed for the calendar year 1997 from a pair of fixed hydrophones located 5 km east of Great Barrier Island, New Zealand. The primary goal of the study was to examine blue whale seasonally and song type as part of a larger worldwide study. Calls were recorded from blue whales of two song types, fin whales, humpback whales, Bryde's whales, and of two unknown call types, each probably produced by Bryde's whales. The peak of calling density was May through September for the blue, fin, and humpback whales. The known Bryde's whale calls occurred year‐round and the probable Bryde's whale calls occurred from May through December. Blue whale songs of a type so far known only from New Zealand waters were detected within 2 km of shore and occurred four times from June to December, whereas the Southern Ocean blue whale songs were detected only further offshore in mid‐winter. Bryde's whale calls were the most abundant type and often occurred near the hydrophones. These data provide a baseline from which future recordings from the same hydrophones could be compared.

Macroinvertebrate diet in intertidal seagrass and sandflat communities: A study using C, N, and S stable isotopes - Daniel Leduc; P. Keith Probert; Russell D. Frew; Catriona L. Hurd (New Zealand Journal of Marine and Freshwater Research, 2006)
Most seagrass community food‐web studies using stable isotopes have been carried out in subtidal habitats during one sampling event. We used C, N, and S stable isotopes to characterise the diet of the dominant macroinvertebrates found in intertidal Zostera capricorni and sandflat communities of southern New Zealand in late summer and winter. The range of ä 13 C and ä 34 S values for Z. capricorni was wide (>5‰), which highlights the importance of accounting for spatial and temporal variability in primary producer isotopic signatures. The range of ä 15 N values for Z. capricorni was comparatively small ( 13 C and ä 15 N signatures suggested that Z. capricorni was a potentially important contributor (24–99%) to the diet of most consumers sampled at the seagrass site, whereas microphytobenthos dominated the diet of the same consumers at the sandflat site. The main exception was the bivalve Austrovenus stutchburyi, which had a diet consisting mostly (up to 85%) of Ulva and Polysiphonia spp. at both sites. S isotopes proved to be of limited use owing to the difficulty of sampling microphytobenthos and to potential non‐dietary sources of 34 S‐depleted sulfur to consumers. Mixing models also suggested that Z. capricorni contributed more to the diet of deposit feeders in August (late winter) than in March (late summer).

Spatial biodiversity patterns in a large New Zealand braided river - Duncan Gray; Mike R. Scarsbrook; Jon S. Harding (New Zealand Journal of Marine and Freshwater Research, 2006)
At the catchment scale, braided rivers are recognised as physically unstable, dynamic landscapes, yet at finer spatial scales they are a mosaic of micro‐habitats including physically unstable braided channels and more stable spring‐sources, spring creeks, and groundwater zones. We investigated benthic invertebrate communities at 103 sites in braided channels, springs and hillslope streams in the Waimakariri River, New Zealand over 3 months. One hundred taxa were identified, including a number of rare phreatic species. Highest total taxonomic richness occurred in springs (81 taxa), whereas main braids and hillslope streams had fewer taxa (54 and 56, respectively). Spring‐fed habitats also had the highest diversity of unique taxa (22), whereas main channels had five and hillslope streams 11 taxa, respectively. Several taxa including the mayfly Deleatidium and orthoclad chironomids were ubiquitous, whereas others such as the flatworm Prorhynchus had restricted habitats. Our results highlight the high spatial heterogeneity of braided river habitats and the importance of springs as centres of invertebrate diversity within braided river catchments.

Links between climate and recruitment of New Zealand hoki (Macruronus novaezelandiae) now unclear - R.I.C. Chris Francis; Mark G. Hadfield; Janet M. Bradford‐Grieve; James A. Renwick; Philip J. H. Sutton (New Zealand Journal of Marine and Freshwater Research, 2006)
We investigated the relationship between climate variation and year‐class strengths for hoki ( Macruronus novaezelandiae ) in New Zealand waters. Our analyses extended those of a previous study, by using an additional 6 years’ data and considering some additional predictands (total year‐class strength and proportion migrating) relating to an alternative stock‐structure hypothesis, and also updated them, by using revised versions of some predictors and year‐class strengths. Predictors considered were based on the Southern Oscillation Index, weather patterns, sea‐surface temperatures, wind speeds, and modelled mixed‐layer depths and nutrient concentrations. In contrast to the earlier analyses we found little or no predictive power for either year‐class strength or proportion migrating. The substantial correlations found in the earlier study were greatly reduced. Such reversals are not uncommon in the climate‐recruitment literature.

Spiny lobster population enhancement: Moderation of emergence behaviour of juvenile Jasus edwardsii reared in captivity - Megan D. Oliver; Alison B. MacDiarmid; Robert A. Stewart; Caleb Gardner (New Zealand Journal of Marine and Freshwater Research, 2006)
Lobster stock enhancement efforts have generally met with limited success owing, in part, to low survival of reseeded juveniles caused by poor development of anti‐predator behaviour. We found that recently‐settled juvenile lobsters reared in captivity for 1 year exhibit significantly higher levels of daytime activity than their like‐sized wild counterparts and that this daytime activity could be reduced by 50% by either rearing the lobsters with a predator or by feeding them at night. In combination, predator presence and night‐time feeding further reduced daytime emergence to low levels. However, a field experiment in which we observed the behaviour and emergence times of captive‐reared lobsters immediately after release on reefs where predators were abundant, showed that regardless of rearing conditions and associated changes in behaviour, lobsters assess the risk of predation and quickly assume nocturnal emergence and activity patterns. This plasticity in behaviour may enable juveniles to maximise foraging range and duration in response to predation pressure.

Marine brown algae introduced to New Zealand waters: First record of Asperococcus ensiformis (Phaeophyta, Ectocarpales, Chordariaceae) - R. D'Archino; W. A. Nelson (New Zealand Journal of Marine and Freshwater Research, 2006)
The brown alga Asperococcus ensiformis is recorded from New Zealand waters for the first time. This species is regarded as an introduced species as is the closely related species A. bullosus, which was first reported to occur in New Zealand in 1957. Although A. ensiformis appears to be flattened and ribbon‐like when examined in transverse section it can be seen to be hollow at the margins. It can be distinguished from similar native species and from A. bullosus by a combination of anatomical and morphological characters.

Phytoplankton assemblages in North Island lakes of New Zealand: Is trophic state, mixing, or light climate more important? - E.F. Ryan; I.C. Duggan; D.P. Hamilton; D.F. Burger (New Zealand Journal of Marine and Freshwater Research, 2006)
Relationships between phytoplankton assemblages and lake trophic state, mixing regime and light climate were investigated in 40 North Island, New Zealand, lakes. We tested the hypothesis that mixing regime is more important than trophic state or light climate in determining the community composition of phytoplankton assemblages which were represented as presence/ absence of cyanobacteria and diatom genera. Mixing regime, characterised as a function of lake size, more accurately predicted summer phytoplankton composition than indices related to trophic state or light regime. Analysis of similarities indicated distinct differences in phytoplankton assemblages between mixed lakes and those that intermittently or periodically stratify. In mixed lakes, a greater variety of cyanobacteria genera than diatom genera were recorded compared with lakes that stratify stably in summer. Conversely, relatively high numbers of diatom to cyanobacteria genera were found in lakes that stratify compared with mixed lakes. Lakes with different trophic states but similar mixing regimes shared very similar summer phytoplankton assemblages. None of the three variables tested was a good predictor of winter phytoplankton composition. Although phytoplankton biomass may be regulated to a large extent by nutrient status, this study shows that mixing regime plays a more important role in regulating phytoplankton composition than either nutrient status or light climate.

Differential absorption of biochemical food components by the scallop Argopecten purpuratus exposed to different salinities and food concentrations - J. M. Navarro; M. J. Fernández‐Reiriz; U. Labarta (New Zealand Journal of Marine and Freshwater Research, 2006)
The scallop Argopecten purpuratus is naturally distributed between central Chile and northern Peru. The objective of the present study was to determine some key acute and acclimated responses of A. purpuratus under a range of salinity and food conditions. The differential absorption of different biochemical components of the diet of this scallop was studied over short time periods (1,3, and 7 days), varied salinity (24, 27, and 30%c), and varied food availability (1.03 and 2.99 mg suspended matter litre ‐1 ). The results showed that variation in salinity explained most of the variance in the food ingestion rate, absorption efficiency, and absorption rates of dietary biochemical components. At high food levels, A. purpuratus acclimatised its absorption efficiency for proteins and carbohydrates after 7 days, but only at salinities of 27 and 30‰. Lipid absorption at 24‰ salinity was negative, with a tendency to show lower values over time. At salinities of 27 and 30‰ the absorption efficiency of lipid was negative for the first 3 days, followed by recuperation with positive values after 7 days of acclimation. However the acclimation process was not complete, as values of absorption at high food levels were significantly lower than those obtained by A. purpuratus at low food levels at the same salinities.

Fecundity of banded wrasse (Notolabrus fucicola) from Otago, Southern New Zealand - Nicholas J. Harwood; P. Mark Lokman (New Zealand Journal of Marine and Freshwater Research, 2006)
To better understand the reproductive biology and to supply crucial data for fisheries management, fecundity of banded wrasse (Notolabrus fucicola) from Otago, southern New Zealand, was investigated over a 12‐month period from January 2004 to January 2005. The spawning season for banded wrasse from Otago was deduced to be from September through to December. The threshold diameter of oocytes undergoing germinal vesicle breakdown in vitro, therefore constituting a batch, was found to be c. 500 μ m. Batch fecundity was accordingly estimated at 74500 ± 34900 eggs/kg body weight. On the basis of cyclic changes in gonadosomatic index and levels of the sex steroids estradiol‐17β and 17α,20β‐dihydroxy‐4‐pregnen‐3‐one, it is likely that wrasse spawn once each lunar cycle during the spawning season, resulting in four batches of eggs each year around the time of the full moon. Calculated annual fecundity ranged between 298000 (± 139600) and 447000 (± 209400) eggs/ kg body weight. Notwithstanding inter‐annual and inter‐locational variation, these fecundity estimates provide a guideline for the management of banded wrasse.

Extreme wave predictions around New Zealand from hindcast data - Scott A. Stephens; Richard M. Gorman (New Zealand Journal of Marine and Freshwater Research, 2006)
A recently implemented wave hindcast for the New Zealand region was used in conjunction with wave‐buoy data to evaluate extreme significant wave height at multiple sites around New Zealand, for the first time. Hindcast storm wave heights were under‐predicted compared with wave‐buoy measurements at three inshore sites, and a method for scaling the hindcast data to improve the comparison of predicted extreme wave heights was explored. Different statistical methods for predicting extreme wave heights were also compared. Offshore, extreme wave heights displayed a north‐south and an east‐west gradient that is in keeping with the mean wave climate, with larger waves in the south and in the west. However, the variation of extreme wave heights between sites was less than the mean wave climate would suggest, because mid‐latitude depressions generate comparatively large waves on the generally more sheltered northeast coast. At the most energetic site to the southwest of the South Island, a 1 in 100‐year return significant wave height H s (100) of 19.3 m and maximum wave height H max(100) > of 45 m were predicted. At the least energetic site to the northeast of the North Island, estimates of H S (100) = 13.9m and H max(100) = 33m were obtained.

Effects of beach erosion on abundance and distribution of toheroa (Paphies ventricosa) at Bluecliffs Beach, Southland, New Zealand - Michael P. Beentjes; Glen D. Carbines; Andrew P. Willsman (New Zealand Journal of Marine and Freshwater Research, 2006)
Data on abundance, distribution, and size structure of toheroa (Paphies ventricosa) on Bluecliffs Beach, Southland, New Zealand from 42 surveys (1966 to 2005) are presented. Toheroa abundance declined from over 2 million adults in the mid 1960s to c. 80000 by 1990 and since then has remained low but relatively stable. The decline mirrors that of other toheroa populations throughout New Zealand. Recent recruitment was highly variable but low compared with historical levels in the 1960s. Length frequency distributions are characteristically bimodal with a strong adult mode and a juvenile mode of variable strength, with relatively few toheroa of intermediate size. The distribution is related to mortality and growth characteristics of Bluecliffs Beach toheroa. Spatial distribution of adult toheroa has progressively changed over the last 40 years—historical distribution included the entire beach and toheroa were most dense just east of the Rowallan Burn. Since 1997, they have been aggregated into one large bed just west of the Rowallan Burn. Toheroa showed intertidal size zonation with small juveniles near high water and larger toheroa near mid to low water. Beach profile surveys were carried out in 1997, 2001, and 2005 to assess the dynamics of beach geomorphology and erosion. The surveys indicated a net loss of sand from the beach between 1997 and 2005, exposing underlying gravel and cobble substrates, and a general erosion of the vegetated dunes. Aerial photos from 1947 reveal that Bluecliffs Beach was homogeneous sand substrate—significant erosion and loss of sand began in the mid 1980s and only c. 54% of the beach surface is now fine/coarse sand. Our results indicate that distribution and abundance of toheroa on Bluecliffs Beach is related to the amount and distribution of sand on the beach. If the erosion continues with loss of sand habitat, the toheroa population may be at risk of collapsing.

A review of rotenone use for the control of non‐indigenous fish in Australian fresh waters, and an attempted eradication of the noxious fish, Phalloceros caudimaculatus - Thomas S. Rayner; Robert G. Creese (New Zealand Journal of Marine and Freshwater Research, 2006)
Rotenone has been used as a piscicide in Australia for c. 45 years. In freshwater systems this use has focused on the control of non‐indigenous fish species. Little of this use has been registered, reported or documented and Australian fisheries researchers and managers are forced to rely on international literature. This paper reviews all available documentation relating to rotenone use in Australia, before discussing some planning and application issues that may be faced by those considering rotenone use. A recent attempt to eradicate a population of noxious poeciliid fish (Phalloceros caudimaculatus) is used as a case study. Although this effort was conducted in a closed system, dense aquatic vegetation prohibited adequate mixing of rotenone and allowed the survival of target fish in areas with low rotenone concentrations. Several months later, the target species persisted at the treated site. If similar systems are to be treated in the future, we suggest that pools are drained before application. We also recommend that the current legislative arrangements for rotenone use in Australia are reviewed, to encourage the proper documentation of eradication events.

A comparison of the morphology and ultrastructure of the diatoms (Bacillariophyceae) Discostella stelligera and D. elentarii from two lakes in Fiordland, New Zealand - J.M. Knapp; P.C. Furey; R.L. Lowe (New Zealand Journal of Marine and Freshwater Research, 2006)
Morphological and ultrastructural variability of the diatoms, Discostella stelligera and Discostella elentarii, were examined from lakes Te Anau and Manapouri, located in Fiordland on the South Island of New Zealand. The objectives of this study were to examine and compare the size variability, frustule morphology, and ultrastructural detail of these taxa, which were recently collected from locations of a different origin than the type localities. To support the current descriptions of the newly erected genus of Discostella and recently described species, D. elentarii, information on morphological characteristics across valve patterns was compared. A principal components analysis of the external valve features of D. stelligera and D. elentarii measured by light microscopy did not separate the two taxa. This close similarity in external morphology highlights the need to optically dissect the valves underneath the light microscope to clearly differentiate between the convex/concave nature of the D. stelligera valves compared with the flat valve of D. elentarii. New external and internal morphological details of D. elentarii were documented with a field emission scanning electron microscope.

Estimating spatial scale of post‐settlement transport potential of Macomona liliana on an intertidal sandflat - Erin T. Petuha; Carolyn J. Lundquist; Conrad A. Pilditch (New Zealand Journal of Marine and Freshwater Research, 2006)
We estimated juvenile transport distance of a common New Zealand bivalve, Macomona liliana, as a function of size, dispersal mode (bedload or water column), and hydrodynamic forcing by combining laboratory (flume and settling chamber) and field (tidal current) data. Live juvenile transport at 7.0 cm s ‐1 flow speed was significantly less than at 17.2 and 28.0cm s ‐1 and most juveniles (80–95%) were transported as bedload. The relationship between juvenile size and fall velocity was positive, and byssus threads significantly reduced fall velocity (≤30%). Our model showed that drifting juveniles can potentially travel much further during a tidal cycle (spring tide 3.3km, neap tide 2.0km) than those in the bedload (

Erratum (New Zealand Journal of Marine and Freshwater Research, 2006)

Freshwater nematodes: ecology and taxonomy. Edited by EyualemAbebe, W.Traunspurger, and I.Andrassy. Published in 2006 by CABI Publishing, Nosworthy Way, Wallingford, Oxfordshire, OX 108DE, United Kingdom. 752 p., hardcover. ISBN: 0–85199–009–6. Price: £125.00/US$225.00Life in the Estuary. By Malcolm B.Jones and Islay D.Marsden. Published in 2005 by Canterbury University Press, Private Bag 4800, Christchurch, New Zealand. 168 p., spiral bound. ISBN: 0–1‐877257‐15‐X. Price: NZ$24.95 (orders: mail@cup.canterbury.ac.nz). - David A. Wharton; Ashley A. Rowden (New Zealand Journal of Marine and Freshwater Research, 2006)

DNA and meristic evidence for two species of giant stargazer (Teleostei: Uranoscopidae: Kathetostoma) in New Zealand waters - Peter J. Smith; Robin P. McPhee; Clive D. Roberts (New Zealand Journal of Marine and Freshwater Research, 2006)
The taxonomic status of the banded giant stargazer in New Zealand waters is uncertain. Mitochondrial DNA partial sequences of the cytochrome b gene and the control region, along with three meristic characters (numbers of dorsal fin rays, anal fin rays, and vertebrae), were compared among six recognised species of Kathetostoma and specimens of the banded giant morph. New Zealand specimens referred to as banded giant stargazer were shown to be a discrete species distinguished from the giant stargazer K. giganteum from New Zealand and the banded K. laeve and K. canaster from Australia, by cytochrome b and control region sequences and meristic counts. This undescribed species occurs over a wide geographic range from the Snares shelf (48°S) to the Norfolk Ridge (32°S) in the Tasman Sea, and is largely sympatric with K. giganteum. The two New Zealand species occupy different depth ranges, with the banded giant stargazer generally occurring in shallower water ( K. giganteum (12–1000 m).

Growth and morphometrics in the New Zealand sea urchin Pseudechinus huttoni (Echinoidea: Temnopleuridae) - Selena Kirby; Miles D. Lamare; Mike. F. Barker (New Zealand Journal of Marine and Freshwater Research, 2006)
We examined somatic growth in the New Zealand sea urchin, Pseudechinus huttoni. This species normally inhabits the continental shelf, but in the New Zealand fiords can be found at shallower depths. These shallower populations provided an opportunity to quantify growth of these deep water sea urchins using chemical tag recapture techniques. Growth was modelled in three Doubtful Sound populations and varied spatially, with maximum test diameter (TD) and maximum growth rates ranging from 33.8 to 42.7mm TD and 2.9mm yr ‐1 to 23.9mm yr ‐1 , respectively. Size‐at‐age modelling suggests that P. huttoni is c. 5–15mm TD at 1 year, 20–30mm TD at 4 years, and adults approach a maximum size of 30–40 mm TD after 6 to 11 years. Growth in continental shelf populations was inferred from measured growth in the fiord population by comparing population statistics (size structures, mean size), morphometrics, and nutritional status among both habitats. Our results indicate that growth of P. huttoni populations on continental shelves varies spatially (with depth), but is within the range of growth measured in the Doubtful Sound populations. A generalised growth model for P. huttoni based on the three Doubtful Sound populations is described by the Brody‐Bertalanffy equation S t = 42.17(1–0.99e (‐0.229t) ).

Utility of morphological data for key fish species in southeastern Australian beach‐seine and otter‐trawl fisheries: Predicting mesh size and configuration - Matt K. Broadhurst; Koenraad K. P. Dijkstra; Dennis D. Reid; Charles A. Gray (New Zealand Journal of Marine and Freshwater Research, 2006)
Samples of 16 key fish species targeted by oceanic prawn trawlers and oceanic and estuarine beach seiners in southeastern Australia were measured for up to 10 morphological dimensions that included: total (Wt) and eviscerated weights (EWt); total (TL), fork (FL), natural (NL), standard (SL), dorsal standard (DSL), and anal standard lengths (ASL); and maximum body height (MH), width (MW), and girth (MG). All partial lengths were indexed against TL to provide linear relationships and, where there were sufficient data, tested for intra‐specific sexual dimorphism. Nearly all species that were sexed demonstrated at least some morphological divergence, and especially for transverse measures; probably owing to different reproductive conditions. Sex‐specific or combined regressions of DSL and ASL and transverse measures versus TL were used to identify the most appropriate: (1) partial length for compliance purposes; and (2) mesh sizes and configurations for the different fishing gears used. Using relevant data describing the smallest commercial‐sized fish species (stout, Sillago robusta and red spot whiting, S. flindersii— 150mm TL) retained in prawn trawls, a new square‐mesh codend (made from 35‐mm mesh hung on the bar) was designed and constructed. The selectivities of this square‐mesh codend and a conventional diamond‐mesh design (40‐mm mesh) were then modelled and compared in a case study. The conventional codend was demonstrated to be non‐selective for the sizes of eastern king prawns and red spot whiting targeted. In contrast, the square‐mesh codend selected red spot whiting across narrow selection ranges (18.88–15.67 mm) and at lengths of 50% retention (143.39–146.32mm TL) that closely corresponded to the estimated maximum mesh opening. The square‐mesh codend also improved selection for eastern king prawns, without impacting on commercial catches. Based on these results, similar predictions were made for appropriate mesh sizes and configurations in oceanic and estuarine beach seines; both of which were demonstrated to comprise minimum mesh sizes that would be non‐selective for the sizes of all targeted fish.

Growth and reproductive phenology of the kelp Lessonia variegata in central New Zealand - Anne‐Maree Schwarz; Ian Hawes; Wendy Nelson; Neil Andrew (New Zealand Journal of Marine and Freshwater Research, 2006)
A field study of Lessonia variegata growing in depths of 8–10 m on the south coast of Wellington, New Zealand investigated morphometric and biomass indices measured on destructively harvested entire algae, rates of blade elongation measured in situ using a blade hole punch technique, and timing of fertility over a 2‐year period. Blade fertility was estimated using a fertility score based on the visual appearance of the reproductive tissue. Lessonia variegata attained a maximum length of 154 cm, a density of 0.8 to 2.1 individuals m ‐2 , and developed an areal biomass ranging from 1700 to 6000 g fresh weight (FW) m ‐2 . The highest proportion of fertile blades (up to 100% of sampled blades) occurred during winter and the end of the fertile period coincided with the onset of the longer days and warmer temperatures of summer. Blade elongation occurred more rapidly in summer months (0.117cm day ‐1 , SE = 0.015) than winter months (0.041cm day ‐1 , SE = 0.009). The slower winter blade elongation rate meant that growth could not overcome tip ablation and average blade length reduced from 51.5cm (SE = 1.9) to 30.8 cm (SE = 1.7) between March and September 2003. Average blade length increased again over the following summer months to 40.7cm (SE = 1.6). Blade biomass dominated total fresh weight biomass (average 64% of total). Two parameters that are relatively easily measured on live macroalgae in situ, holdfast diameter and girth of all stipes collectively, predicted total biomass with an r 2 = 0.91, suggesting these could be useful tools for assessment of this potentially harvestable resource on Wellington's south coast.

Lack of divergence in the mitochondrial cytochrome b gene between Macruronus species (Pisces: Merlucciidae) in the Southern Hemisphere - Carlos Olavarría; Fernando Balbontín; Rolando Bernal; C. Scott Baker (New Zealand Journal of Marine and Freshwater Research, 2006)
Two species of grenadier, the blue grenadier (or hoki) Macruronus novaezelandiae and the Patagonian grenadier M. magellanicus, have been recorded in the Southern Hemisphere with disjunct distributions along southern Australia‐New Zealand and southern Chile‐Argentina, respectively. The extent of genetic difference between these two putative species was examined using partial sequences ( n = 44; 405 bp) of the mitochondrial DNA cytochrome b gene in a phylogenetic analysis and in an analysis of molecular variance (AMOVA). Our analysis showed a lack of genetic differentiation between species ( F ST = ‐0.02275, F ST = ‐0.00250) and among stocks. This absence of genetic differences is consistent with recent larval and adult morphology data suggesting that the two species should be synonymised. A comparable lack of genetic isolation has been observed in other closely related taxa (genera Merluccius and Micromesistius ) with similar disjunct distributions across the Southern Hemisphere.

Confirmation of morphological differences between Anguilla australis australis and A. australis schmidtii - Shun Watanabe; Jun Aoyama; Katsumi Tsukamoto (New Zealand Journal of Marine and Freshwater Research, 2006)
A statistical analysis of morphological characters in Anguilla australis australis and A. australis schmidtii was performed for a review of the taxonomic status of A. australis. Twenty‐four external measurements were taken in each of 125 specimens and total numbers of vertebrae of 78 specimens were compared for the two subspecies. Previously published data on total vertebrae, branchostegal rays, and pectoral rays were also statistically analysed. We found a significant difference between the two subspecies in 16 external morphometric characters, total number of vertebrae, and number of branchostegal rays. The analysis revealed that considerable morphological differences exist between these two subspecies of A. australis, despite a recent molecular study supporting a common gene pool. Further examination of morphological, molecular, genetic, and ecological information will be required to resolve the taxonomic status of the two subspecies.

Tidal circulation in Tasman and Golden Bays: Implications for river plume behaviour - Benjamin J. Tuckey; Mark T. Gibbs; Benjamin R. Knight; Paul A. Gillespie (New Zealand Journal of Marine and Freshwater Research, 2006)
An investigation into the tidal residual circulation in the Tasman/Golden Bays system was performed. This investigation involved collecting hydrographic and current meter data, and configuring a numerical circulation model. The model was able to reproduce the gross features of the major tidal flows within the system revealed by the data. The simulated tidal residual circulation conformed to that previously suggested, except along the western side of Tasman Bay where this investigation suggests that residual flows move northwards. The validated model was then used to produce simulations of the fate of the plumes from the major rivers. Salinity field simulations describing different river flow and wind direction/velocity scenarios suggest that the Motueka River plume can cover considerable proportions of western side Tasman Bay, extending into Golden Bay during flood conditions. The embedded sediment transport model was also used to investigate the fate of fine sediments entering the bays. Simulated distribution patterns of fine sediments entering the bays from the four major tributaries were found to be consistent with existing bathymetric and seabed substrate characteristics.

A method for estimating inherent optical properties of New Zealand continental shelf waters from satellite ocean colour measurements - Matthew H. Pinkerton; Gerald F. Moore; Samantha J. Lavender; Mark P. Gall; Kadija Oubelkheir; Kenneth M. Richardson; Philip W. Boyd; James Aiken (New Zealand Journal of Marine and Freshwater Research, 2006)
We describe a method to estimate spectral absorption and backscattering coefficients between 412 and 555 nm from measurements of remote sensing reflectance across the visible spectrum. The algorithm described is applicable to ocean colour satellite measurements (e.g., SeaWiFS). In situ measurements of inherent and apparent optical properties were made at 19 coastal stations off the north coast of New Zealand's South Island in December 2001. These measurements were used to parameterise a bio‐optical model that estimates remote sensing reflectance from concentrations of water constituents. The model generated a large number (5000) of modelled ocean colour reflectance spectra that represented a greater range of biogeochemical conditions than were measured in the study area. These modelled values spanned a wide range of chlorophyll concentrations (0.1–10 mg m ‐3 ), total suspended particulate material concentrations (0.1–50 g m ‐3 ), and dissolved yellow substance absorptions (0.01–3 m ‐1 ). The modelled spectra were then used to test the performance of the algorithm. The median ratio of algorithm values to target values was 0.84 (absorption), and 0.80 (backscatter), and the median absolute errors were 33% (absorption) and 36% (backscatter) across two orders of magnitude. The r 2 values between target and algorithm values of inherent optical properties in log‐log space were 0.89 for backscatter, and varied with wavelength for absorption from 0.79 (412 nm), 0.72 (443 nm), 0.63 (490 nm), 0.55 (510 nm), and 0.21 (555 nm).

Relationships between mosquito densities in artificial container habitats, land use and temperature in the Kapiti‐Horowhenua region, New Zealand - Paul T. Leisnham; Philip J. Lester; David P. Slaney; Philip Weinstein (New Zealand Journal of Marine and Freshwater Research, 2006)
Land‐use change, including deforestation for agriculture and urbanisation, has coincided with increases in vector‐borne diseases worldwide. Land‐use change is likely to regulate immature (larvae and pupae) mosquito populations through changes in local temperatures owing to manifold changes to the physical environment. However, we still poorly understand the relationship between land use, water temperature, and immature mosquito density. We conducted a field study in the Kapiti‐Horowhenua region, New Zealand, to examine the relationship between land use, water temperature, and immature mosquito population dynamics in aquatic larval habitats. Artificial container habitats were sampled for immature mosquitoes in native forest, pastureland and urbanland, at three replicate locations, from October 2002 to April 2003. The endemic species Culex pervigilans constituted 94.5% of all late‐instar larvae collected, the remainder being the exotic Ochlerotatus notoscriptus. On average, significantly higher pupal mosquito densities were recorded from urbanland containers compared with pastureland and native forest containers. A similar trend was observed for total mosquito densities, but did not reach statistical significance. Water temperatures in native forest typically did not show as much variation as those in urbanland and pastureland. Pastureland containers had significantly higher maximum and average daily water temperatures and lower minimum daily water temperatures than native forest containers. Using multiple regression analysis, total mosquito densities were best explained by the quadratic effects of maximum daily temperature and average daily temperature. The results of this study show that pastoral and urban development can increase water temperatures in container habitats, and that land‐use change may be responsible for higher immature mosquito densities when habitat water temperatures do not consistently exceed a high threshold.

Two new species of Tetranchyroderma (Gastrotricha, Macrodasyida) from a sandy beach in southeastern Australia - Warwick Nicholas; M. Antonio Todaro (New Zealand Journal of Marine and Freshwater Research, 2006)
Two new species of Tetranchyroderma are described from a sandy beach in southeastern Australia. Both species belong to the subgroup of the genus in which the dorsal surface of the body is covered with pentancres and in which head sensorial organs (tentacles and/or pestle organs) are absent. Tetranchyroderma pentaspersus sp. nov. is small, 178–244μm long, and distinguished by possessing exceptionally large pentancres, c. 30 rows, with the central tine c. 15μm long on the trunk, though shorter on the head; lateral tines c. 60% as long. The adhesive apparatus consists of four pairs of anterior adhesive tubules (TbA), nine pairs of ventro‐lateral tubules (TbL), and eight posterior tubules (TbP), with two of the latter at the end of each caudal pedicle and four very small in between the caudal pedicles; dorsal and ventral tubules and “cirrata” are absent. Tetranchyroderma australiense sp. nov. is larger, 330–390μm long, possesses c. 70 rows of smaller pentancres, with all five tines of equal length. The adhesive apparatus consists of four pairs of TbA, eleven pairs of TbL, one pair of dorsal adhesive tubules (TbD), and four TbP, the latter equally distributed at the end of two caudal pedicles; ventral tubules and cirrata are absent. Possible synonymy between the new species and Tetranchyroderma sp. 7 of Valbonesi & Luporini (1988) from Somalia is discussed.

Offshore distribution of Hector's dolphins at Banks Peninsula, New Zealand: Is the Banks Peninsula Marine Mammal sanctuary large enough? - Elisabeth Slooten; William Rayment; Steve Dawson (New Zealand Journal of Marine and Freshwater Research, 2006)
Aerial surveys of Hector's dolphins were carried out to evaluate the effectiveness of the Banks Peninsula Marine Mammal Sanctuary. In summer, the proportion of sightings inside the 4 nautical mile offshore boundary of the sanctuary was 79%. This dropped to just over 35% in winter. These estimates were used in a population viability analysis to determine whether the sanctuary needs to be extended to reduce dolphin bycatch to sustainable levels. We followed the standard procedure for setting limits on marine mammal bycatch in the United States to calculate a bycatch limit of 1.6 or 2.8 dolphins per year (depending on whether the sanctuary population is included). If the offshore boundary was extended to 15 nautical miles, the sanctuary would need to be extended alongshore north and south by more than 30 nautical miles to reduce bycatch to 2.8, or north and south by 60 nautical miles to reduce bycatch to 1.6 dolphins per year.

Seagrass biodiversity of the Fiji and Samoa islands, South Pacific - Posa A. Skelton; G. Robin South (New Zealand Journal of Marine and Freshwater Research, 2006)
Five seagrass species and one subspecies distributed in two families (Hydrocharitaceae and Cymodoceaceae) are reported from the Fiji Islands and the Samoan Archipelago. The Fijian seagrass flora comprises Halophila decipiens, H. ovalis, H. ovalis subspecies bullosa, Halodule pinifolia, Halodule uninervis, and Syringodium isoetifolium. Halophila ovalis, H. ovalis ssp. bullosa, and S. isoetifolium are the only taxa recorded from Samoa. Records of Thalassia hemprichii, Cymodocea serrulata, Halophila minor, and Halophila ovata credited to Fiji and Samoa are either erroneous or remain to be verified. All the species reported herein have an Indo‐Pacific distribution, except H. ovalis ssp. bullosa endemic to Fiji, Tonga, and Samoa. Halophila decipiens is confirmed for the first time from Fiji with all specimens collected subtidally from 10–25 m depth.

Sensory qualities of the New Zealand abalone, Haliotis iris, reared in offshore structures on artificial diets - Mark A. Preece (New Zealand Journal of Marine and Freshwater Research, 2006)
A trained taste‐testing panel was used to assess taste differences in cultured New Zealand abalone ( Haliotis iris Martyn 1784) fed two different artificial diets (Coast Biologicals and Makara™). The trained taste‐testing panel could not detect any difference in taste between abalone grown on the two artificial diets. Any difference that might have been produced by the artificial diets could have been masked by abalone consuming drift algae entering their grow out structures. A consumer panel was used to determine whether meat of cultivated abalone was preferred over that of wild caught abalone. The panel indicated a preference in texture and overall acceptability for cultivated abalone fed on artificial diets over abalone caught from a locally occurring wild population. No preference for flavour of wild or cultivated abalone was detected. Neither texture nor flavour related positively to the overall acceptability of abalone.

Comparison of the ectosymbionts and parasites of an introduced crab, Charybdis japonica, with sympatric and allopatric populations of a native New Zealand crab, Ovalipes catharus (Brachyura: Portunidae) - Aroha Miller; Graeme J. Inglis; Robert Poulin (New Zealand Journal of Marine and Freshwater Research, 2006)
The success of biological invaders is often attributed to escape from specialist enemies in their natural range, such as predators and parasites. For enemy escape to have direct consequences in competitive interactions, invaders need to be less vulnerable to enemies than native competitors in the region they invade, but first the presence of these enemies must be established. We investigated the macroparasite and ectosymbiont fauna of the recently introduced portunid crab Charybdis japonica, and compared it with sympatric and allopatric populations of the native New Zealand portunid, Ovalipes catharus. A total of 468 crabs (350 O. catharus and 118 C. japonica ) were collected from six harbours throughout New Zealand (Whangarei, Waitemata, Nelson, Lyttelton, Dunedin, and Bluff) and the identity, incidence and prevalence of ectosymbionts and parasites were compared among the different populations. Charybdis japonica and O. catharus harboured different ectosymbionts. Serpulid polychaete tubes occurred on the exoskeleton of 85.4% of C. japonica examined, but were absent from O. catharus. The bryozoan, Triticella capsularis occurred on 97.4% of O. catharus but was not found on C. japonica. Few endoparasites were present in either species. An unidentified juvenile ascaridoid nematode occurred in the hindgut of 5.9% of C. japonica, but was not found in sympatric populations of O. catharus. A second, unidentified species of ascaridoid nematode occurred in 7.1% of O. catharus from Nelson, but was not present in specimens from the five other harbours sampled. Melanised lesions were observed in the muscle tissue of almost half (46.6%) of the C. japonica examined. Histological examination showed these to be of two types: (1) spherical bodies resembling melanised trematode metacercariae; and (2) lesions consistent with wound repair. Lesions were not observed in O. catharus. Although the identity of parasites and epibionts carried by each species differed, both C. japonica and O. catharus had relatively low parasite species richness. We could not test whether the introduced portunid, C. japonica, is any less vulnerable to parasite enemies than the New Zealand portunid, O. catharus.

Comparing herbivory effects of stream macroinvertebrates on microalgal patch structure and recovery - Joseph R. Holomuzki; Rex L. Lowe; Jennifer A. Ress (New Zealand Journal of Marine and Freshwater Research, 2006)
We studied short‐term herbivory and recovery of microalgal communities grazed by snails ( Potamopyrgus antipodarum ) , mayflies ( Deleatidium spp.), and caddisflies ( Pycnocentrodes aeris ) in microcosms containing low algal food supplies characteristic of grazer‐controlled streams. Herbivore biomass was standardised across single‐species treatments to assess grazing effects owing to taxon‐specific differences in feeding modalities. Potamopyrgus decreased algal biovolumes, on average, by 56% in 4 days, and multidimensional scaling (MDS) showed that snail‐grazed microalgal communities were distinct. The erect diatoms Synedra ulna and Staurosirella leptostauron were less abundant, and basal cells of the chlorophyte Stigeoclonium lubricum were more abundant, in snail‐containing treatments than in ungrazed controls and other species treatments. In contrast, more mobile caddisfly and mayfly larvae failed to significantly alter algal biomass and assemblage, suggesting radular mouthparts of snails were more effective at removing algae from the diatom‐dominated communities than the bladelike or brushing mouthparts of caddisflies and mayflies, respectively. Microalgal communities recovered to pre‐grazed conditions in all treatments after 4 days in a grazer‐free, outdoor flume. Diatoms also dominated the recovery phase, but the erect forms S. ulna and S. leptostauron were more abundant during recovery than grazing. Wilhm's diversity decreased after recovery, suggesting grazing had a positive effect on algal diversity. Thus, herbivory primarily by Potamopyrgus affected microalgal patch structure, and hence the starting successional sere, but had no detectable effect on short‐term successional direction in these fast‐recovering communities.

Population‐genetic structure in the New Zealand caddisfly Orthopsyche fimbriata revealed with mitochondrial DNA - Peter J. Smith; S. Margaret McVeagh; Kevin J. Collier (New Zealand Journal of Marine and Freshwater Research, 2006)
Nucleotide sequences of 422 base pairs of the cytochrome c oxidase subunit I (COI) gene were used to assess phylogeographic structure in the New Zealand hydropsychid caddisfly Orthopsyche fimbriata. A hierarchical examination of populations from 16 streams at different spatial scales in the central and northern North Island of New Zealand found 23 haplotypes. Most regions were characterised by unique haplotypes with genetically differentiated populations at the 7+ km scale. Haplotype diversity was high (0.5–0.8) at most sites, but low (0.2–0.3) in Northland and zero at some central sites. Analyses of molecular variance found significant genetic diversity among regions (66%) and among catchments (55%). Most population pair‐wise F ST tests were significant, with non‐significant pair‐wise tests among sites in the central region and pairs of sites between neighbouring streams. The levels of sequence divergence are interpreted as the result of divergence of relict populations in multiple refugia, leading to the evolution of regionally unique haplotypes. The low diversity in some central region populations is interpreted as resulting from re‐colonisation following extinctions associated with historical volcanic events.

Depletion‐based population estimates for western rock lobster (Panulirus cygnus) fishery in Western Australia - Ian Wright; Nick Caputi; James Penn (New Zealand Journal of Marine and Freshwater Research, 2006)
A depletion technique was applied to the western rock lobster fishery in Western Australia for the non‐migrating part of the season, March to June. The catch for the migrating part of the fishery was used to estimate the annual exploitation for the whole season. To take into account environmental effects (water temperature and swell) on catchability that affect the assumptions of the depletion technique, estimates of the changes in catchability between March and June of each year were obtained. The trends in catchability, residual biomass and exploitation for three zones of the fishery since the 1983/84 season were examined. These show that the exploitation in the north coastal zone decreased from c. 75% in the early 1990s to c. 60% in the mid 1990s as a result of a major change in management in 1993/94 (including 18% nominal effort reduction and increased protection of mature females). However, in the last 10 years exploitation has increased again to c. 75%, mainly owing to increases in catchability (e.g., efficiency increases) as there has been little change in the nominal effort. The results from this study provide some insight into changes in catchability that can be used in other stock assessment techniques such as length‐based assessments.

Land‐use impacts and water quality targets in the intensive dairying catchment of the Toenepi Stream, New Zealand - Robert J. Wilcock; Ross M. Monaghan; John M. Quinn; Alan M. Campbell; Bruce S. Thorrold; Maurice J. Duncan; Alec W. McGowan; Keith Betteridge (New Zealand Journal of Marine and Freshwater Research, 2006)
Water quality monitoring in Toenepi Stream, New Zealand, started in 1995 in a study of dairy farming influences on lowland stream quality and has continued since then with brief interruptions. Surveys have provided information about changes in farm and soil management practices as they relate to environmental sustainability. Although average water quality in Toenepi Stream has changed little during 1995–2004, there have been some notable improvements. Water clarity measured by black disc has improved from 0.6m to 1.5m, and median ammonia‐N and nitrate‐N concentrations have declined by 70% and 57%, respectively. The frequency and magnitude of extreme concentrations have declined—most notably for nitrogen (N) forms, which also had decreased mean values. Specific yields for suspended solids (SS) and phosphorus (P) forms in 2002–04 were 47–67% of 1995–97 values, mainly because of lower water yields. Reduced specific yields for N forms in 2002–04 (34–37% of 1995–97 yields) were also attributable to lower mean concentrations in stream water. Faecal bacteria concentrations have not abated and are on average 2–3 times recommended guideline values for contact recreation. Fewer dairy farms and an increased proportion irrigating dairyshed effluent to land, rather than discharging it to the stream via two‐pond systems, were likely causes of improvement in water quality. Water quality targets were developed for Toenepi Stream to achieve contact recreation criteria for the Piako River (downstream) and for intrinsic habitat values for Toenepi Stream. A range of mitigation measures has been formulated to meet these targets, but substantial uptake of sustainable farming practices is needed to improve water quality in Toenepi Stream.

Quantifying contamination of streams by 1080 baits, and their fate in water - Alastair M. Suren (New Zealand Journal of Marine and Freshwater Research, 2006)
Forty‐eight streams were surveyed during four aerial 1080 operations in New Zealand's South Island to quantify the number of 1080 baits falling into streams. Bait size used in each operation varied considerably: small (2g) baits in Marlborough, medium‐sized (6–7 g) baits in Canterbury and the West Coast, and large (11 g) baits in Lewis Pass. The number of baits found in streams varied widely, and was related only to bait size, with more of the small baits found in streams than the large baits. There was no relationship between stream width or canopy cover and the number of baits found within a stream. These findings suggest that the potential number of baits falling into a stream cannot be calculated from the bait application rate and the stream size. The fate of submerged 1080 baits was also examined in a laboratory flow tank. Submerged baits fragmented within 3–4 days. 1080 was rapidly leached from submerged baits: almost 50% of original 1080 had leached after 5h, and >90% after 24h. Such rapid leaching reflects 1080's high solubility. This finding has implications for water quality monitoring programmes used during 1080 drops, as samples should be collected within 4–8h of potential contamination to detect presence of 1080.

Biology and ecology of fishes. 2nd edition. By J. S.Diana. Published in 2003 by Cooper Publishing Group, P.O. Box 1129, Traverse City, MI 49686, United States. 498 p., hardcover. ISBN 1–884125–98–0. Price: US$80.00. - Gerard P. Closs (New Zealand Journal of Marine and Freshwater Research, 2006)

Cyanobacterial blooms appear to be driven by top‐down rather than bottom‐up effects in the Lower Karori Reservoir (Wellington, New Zealand) - K.F. Smith; P.J. Lester (New Zealand Journal of Marine and Freshwater Research, 2006)
The lower reservoir of the Karori Wildlife Sanctuary (Wellington) has experienced cyanobacterial blooms for the last 8 years. In this study, we sought to test the role of nutrient resources (bottom‐up) versus cascading effects of zooplanktivorous perch (Perca fluviatilis) (top‐down) in controlling cyanobacteria in this lake. A 2×2 factorial field experiment was performed within plastic enclosures positioned in the lake, using four treatments: (1) the addition of juvenile perch; (2) the addition of nitrogen and phosphorus; (3) the addition of juvenile perch and of nitrogen plus phosphorus; and (4) a control treatment of no perch or nutrient addition. Four species of Anabaena were found with the dominant species being A. lemmermannii. Cyanobacterial abundance was significantly higher in treatments with perch. The addition of nutrients had no significant effect on cyanobacterial densities, but there was a weak fish × nutrient interaction on cyanobacteria abundance. There was no overall difference in total zooplankton abundance in any of the treatments. However, zooplankton species diversity was increased and large crustaceans were at higher densities in treatments without perch. Community composition of both phytoplankton and zooplankton species was altered by the addition of juvenile perch and nutrients. Our results suggest that an eradication of perch may cause a reduction in cyanobacteria abundance with the plankton being dominated by both larger phytoplankton and zooplankton species.

Salinity controls the upper depth limit of black corals in Doubtful Sound, New Zealand - Louise T. Kregting; Mark T. Gibbs (New Zealand Journal of Marine and Freshwater Research, 2006)
The New Zealand endemic black coral Antipathes fiordensis is found in Fiordland in shallow depths (c. 5 m) compared with depths of other black corals worldwide. This is considered to be a result of the low light levels caused by the tannin‐rich, surface low‐salinity layers (LSLs) of water that are characteristic of the fiords. However, low salinity may also affect the distribution of black corals because of osmotic stress. We found a strong relationship between the upper limit of coral colonies and the salinity gradient along Doubtful Sound and no significant relationship between the upper depth limit of A. fiordensis and the underwater light field. This suggests that salinity, rather than light levels, plays a dominant role in controlling the upper depth limit of A. fiordensis. This result was supported by a salinity tolerance experiment in which coral colonies were held in situ in a range of salinities (6–32 psu). This experiment revealed that corals can tolerate salinities of between 20 and 30 psu for up to 6 h as long as lowered salinities were periodically interrupted by higher, less detrimental salinities (>32 psu). Although LSLs may reduce incoming irradiation, the extreme upper limit of A. fiordensis in Doubtful Sound appears to be controlled by the salinity field.

New softnose skate genus Brochiraja from New Zealand (Rajidae: Arhynchobatinae) with description of four new species - Peter R. Last; John D. McEachran (New Zealand Journal of Marine and Freshwater Research, 2006)
Brochiraja, a new rajid genus, is defined for a group of softnose skates from the deep sea adjacent New Zealand. The group presently contains six species: Brochiraja asperula (Garrick & Paul), B. spinifera (Garrick & Paul), and four new taxa, B albilabiata sp. nov., B. aenigma sp. nov., B. leviveneta sp. nov., and B . microspinifera sp. nov. These species are closely related to members of the Indo‐Pacific genus Notoraja but three of them differ from all other softnose skates (arhynchobatins) in at least one presumed synaphomorphy—the presence of a bifurcated thorn on the mid‐distal rostral cartilage that is strongly evident in juveniles and variably reduced in adults. Placement of B. aenigma, known only from the post‐juvenile holotype, lacks these thorns so its placement in the genus is provisional. The new species differ from B. asperula, B. spinifera, and each other, in coloration, morphometrics, squamation, and vertebral and pectoral‐fin counts. The existence of multiple morphotypes of the two pre‐existing nominal taxa suggests that the New Zealand skate fauna has vicariated from populations isolated from each other on the remote continental slopes, seamounts, and plateaus of the South‐West Pacific.

Locally generated tsunami along the Kaikoura coastal margin: Part 2. Submarine landslides - Roy Walters; Philip Barnes; Keith Lewis; James R. Goff; Jason Fleming (New Zealand Journal of Marine and Freshwater Research, 2006)
An examination of the underwater landscape along the northeast coast of the South Island, New Zealand, identified a substantial potential for a submarine landslide in Kaikoura Canyon. A numerical model was applied to calculate runup and inundation arising from a local tsunami generated by such a landslide. The model is based on the Reynolds‐averaged Navier‐Stokes (RANS) equation and used a finite element spatial approximation, implicit time integration, and a semi‐Lagrangian advection approximation. The results indicate that a landslide‐generated tsunami represents a large potential hazard to the area from South Bay to Oaro, South Island, New Zealand, and has the potential to generate large tsunami runup heights along this section of coast. In addition, the tsunami events are characterised by a short time interval between generation and runup.

Geographic distribution of Pfiesteria spp. (Pfiesteriaceae) in Tasman Bay and Canterbury, New Zealand (2002–03) - Lesley L. Rhodes; Janet E. Adamson; Parke A. Rublee; Eric Schaefer (New Zealand Journal of Marine and Freshwater Research, 2006)
The fish‐killing heterotrophic dino‐flagellate species Pfiesteria piscicida and P. shumwayae (also Pseudopfiesteria shumwayae ) were present throughout New Zealand and were residents of Tasman Bay's well‐flushed estuaries and Canterbury's brackish lakes, as determined by polymerase chain reaction‐based detection assays. The two species occurred in a wide range of salinities and temperatures, although detection was restricted seasonally from spring through to autumn, except for one incidence in the shallow waters of Wairewa/ Lake Forsyth, Canterbury, in the winter of 2003. The DNA sequencing data indicated that P. shumwayae may encompass a suite of genetically closely related species. The presence of Pfiesteria in New Zealand is not considered an immediate risk to fish or human health given the current low‐to‐moderate nutrient concentrations in New Zealand's estuaries and brackish lakes. However, increases in nutrient loadings could pose a risk, as has occurred in eastern United States estuaries.

Molecular analysis of bacterial communities in groundwaters from selected wells in the Hutt Valley and the Wairarapa, New Zealand - Margo Van Bekkum; James P. Sainsbury; Christopher J. Daughney; Geoffrey K. Chambers (New Zealand Journal of Marine and Freshwater Research, 2006)
This study constitutes the first attempt to examine the microbial diversity in New Zealand groundwater samples using a culture‐ and cloning‐independent technique. In this investigation, 18 distinct terminal restriction fragment length polymorphism (T‐RFLP) peak profiles were generated from groundwater samples collected from various sites and aquifers in the Hutt Valley and the Wairarapa. Most peak profiles were similar, implying only small differences in microbial community structure in the groundwater samples collected, and relatively low microbial diversity compared to non‐aquifer water samples. Nonetheless, subtle but systematic differences in T‐RFLP peak profiles were observed between the aquifers and, in some instances, for groundwater samples collected at different locations within a single aquifer. Differences in the peak profiles appeared to be related to groundwater chemistry, particularly to concentrations of iron, manganese, nitrogen, and sulfur.

Consumption of baits containing sodium fluoroacetate (1080) by the New Zealand freshwater crayfish ( Paranephrops planifrons ) - Alastairm Suren; Martin L. Bonnett (New Zealand Journal of Marine and Freshwater Research, 2006)
Native freshwater crayfish (koura: Paranephrops planifrons ) were exposed to baits containing sodium fluoroacetate (1080) to determine whether they consumed baits in the presence of other food (detritus and invertebrates), and whether such consumption was lethal. Crayfish were collected from streams and placed individually into 50 cages in a large “stream simulator”, divided into a riffle and pool habitat. A single 1080 bait (mean weight = 6.4g) containing c. 0.15% 1080 (i.e., 9.6 mg) was added to each of 20 cages in each habitat. Non‐toxic baits were added to five additional control cages within each habitat. A further five crayfish were placed in aquaria to act as double controls. Replicate crayfish exposed to 1080 baits were collected from both habitats after 1, 2, 4, and 8 days and analysed for 1080 in their viscera and tail muscle. Crayfish exposed to non‐toxic bait, and double control crayfish were collected after 8 days and analysed for 1080. The highest concentration of 1080 (1.1 μ g litre ‐1 ) in water collected from the simulator occurred after 2 days, and no residual 1080 was detected after 8 days. Crayfish consumed baits, even in the presence of other food items, but no mortality was observed. The highest 1080 concentrations were 3.3 μ g g ‐1 body tissue in the viscera, and 5 μ g g ‐1 in tail muscle. 1080 concentration in the viscera was positively related to that in the tail muscle. 1080 concentrations declined in the tail muscle between days 4 and 8, suggesting that sub‐lethal doses of 1080 could be successfully metabolised. The potential risk to humans consuming crayfish containing 1080 is considered virtually nonexistent, as an 85 kg person would need to consume over 40 kg of contaminated crayfish tails in a single sitting to receive an LD 50 dose.

Oxygen consumption and enzyme activity of the subtidal flat oyster (Ostrea chilensis) and intertidal Pacific oyster (Crassostrea gigas): Responses to temperature and starvation - Brendon J. Dunphy; Rufus M.G. Wells; Andrew G. Jeffs (New Zealand Journal of Marine and Freshwater Research, 2006)
Intertidal Pacific oysters (Crassostrea gigas) and subtidal flat oysters (Ostrea chilensis) were held at 10, 15, or 20°C without food for 16 weeks. Rates of oxygen consumption in the subtidal oyster were more sensitive to temperature than those of the intertidal oyster, but temperature sensitivity decreased in starved Pacific oysters. Metabolic fuel reserves of glycogen in the adductor muscle were markedly higher in C. gigas, and decreased with starvation. Higher activities of the key metabolic enzymes, strombine dehydrogenase, alanopine dehydrogenase, and citrate synthase were found in C. gigas than in O. chilensis, indicating greater scope for energy production. These observations were consistent with the greater aerobic scope and glycolytic potential of C. gigas in the thermally variable intertidal environment, and in the face of severe nutritional challenge. Ostrea chilensis was metabolically challenged by warm temperatures and food deprivation, factors that need to be considered in the development of aquaculture methods for this species.

Changes in subtidal macroinvertebrate community structure in Wellington Harbour (New Zealand) following a large‐scale natural die‐off - Jonathan P. A. Gardner; Robert G. Wear (New Zealand Journal of Marine and Freshwater Research, 2006)
We examined the processes of recolonisation and recovery of the benthic biota at nine subtidal stations 8 and 12 months following a bloom of the toxic dinoflagellate Karenia brevisulcata in Wellington Harbour, New Zealand. Compared with 2 months post‐bloom, number of species ( S ) was significantly higher at three of six stations, numbers of individuals (N) increased significantly at four of six stations, species diversity ( H ’) increased significantly at one of six stations and decreased significantly at one of six stations, and evenness ( J ’) decreased significantly at three of six stations. At the three new stations for which we have data only for 8 and 12 months post‐bloom, S increased significantly with time on one occasion, N increased significantly on two occasions, H’ increased significantly on one occasion, and J’ decreased significantly on one occasion. At all stations, changes in biomass (B) showed no significant trend, were all station and taxon‐specific, and B was a poor indicator of recolonisation and succession. Biological communities became more similar between stations with increasing time after the bloom. Multidimensional scaling (MDS) analysis separated two stations with high levels of natural disturbance from the seven stations which were affected by the bloom. MDS analysis of pre‐ and post‐bloom data for four stations indicated that the three stations most affected by the bloom followed trajectories of recolonisation and succession consistent with rapid but incomplete community recovery. Despite the widespread and devastating nature of the bloom, this event was only a minor perturbation to the ecology of soft substrate communities in the harbour.

Benthic community structure and water column characteristics at two sites in the Kermadec Islands Marine Reserve, New Zealand - Jonathan P. A. Gardner; Martin J. Curwen; Joanne Long; Robert J. Williamson; Ann R. Wood (New Zealand Journal of Marine and Freshwater Research, 2006)
The Kermadec Islands Marine Reserve (KIMR), which is located at 30°S, is New Zealand's largest marine reserve at 748 000 ha, and its biota is composed of a mix of warm temperate, subtropical, and tropical species. A depth‐stratified ecological survey was conducted of the abundance and percentage cover of macrobenthic species and of the water column at two sites (Meyer Island and West Chanter Island), 2km apart. Significant differences in benthic community structure and in water column turbidity and chlorophyll concentrations were observed between the two sites despite their proximity and physical similarity. Compared with other “snapshot” surveys of benthic community structure at sites within the KIMR there was a high degree of similarity among the species observed, but often a low degree of similarity in species abundance or percentage cover as a function of depth. We suggest that despite its isolation and the degree of difficulty of working at this location, a full‐scale ecological survey of the coastal marine biota of the KIMR is warranted to better understand New Zealand's subtropical marine biota and its affinities with other marine biotas of the South Pacific.

Locally generated tsunami along the Kaikoura coastal margin: Part 1. Fault ruptures - Roy A. Walters; Philip Barnes; James R. Goff (New Zealand Journal of Marine and Freshwater Research, 2006)
Tsunami are generated by sudden movements of the ocean bed or by objects such as subaerial landslides and bolides falling into the ocean. An examination of the geophysical setting for the northeast coast of the South Island, New Zealand, identified a substantial potential for submarine fault ruptures and submarine landslides. To examine possible effects of a tsunami, a numerical model was applied to calculate runup and inundation arising from locally‐generated tsunami along this section of the coast. The specific events considered were fault ruptures on the Kekerengu Bank Fault and two lesser faults, and a submarine landslide in Kaikoura Canyon. The model is based on the Reynolds‐averaged Navier‐Stokes (RANS) equation and used a finite element spatial approximation, implicit time integration, a semi‐Lagrangian advection approximation, and a simple method for treating non‐hydrostatic pressure variations. The results indicate that the different generation events have significant effects on different parts of the coastal margin. For the fault‐rupture events, the northern coast of the study area is very exposed to damage from a potential rupture of the Kekerengu Bank Fault. A concern is that the highest waves near Kaikoura would be a result of late arrival of coastally‐trapped waves and would be delayed by up to 1.5h after the fault‐rupture event.

Microbial assemblage during the spring‐summer transition on the northeast continental shelf of New Zealand - J. A. Hall; K. Safi; M. R. James; J. Zeldis; M. Weatherhead (New Zealand Journal of Marine and Freshwater Research, 2006)
The northeast shelf of the North Island of New Zealand was sampled on four occasions from early spring to late summer in 1996–97. During this period, tight linkages between the physical and chemical forcings and the response from the microbial food‐web were observed. During bloom conditions in early spring the phytoplankton population was dominated by large diatoms with the picophytoplankton contributing an average of 8% of the phytoplankton biomass. The picophytoplankton fraction increased to contribute a mean of 57% of the phytoplankton biomass in late summer when upwelling had ceased, the water column was strongly stratified and dissolved inorganic nitrogen concentrations were negligible. The changes in the phytoplankton assemblage were accompanied by changes in the microzooplankton population. In early spring the microzooplankton population was dominated by larger species, including copepod nauplii and >20 μm aloricate ciliates, with copepod nauplii contributing up to 50% of the microzooplankton biomass in early and late spring. Peak microzooplankton biomasses of 880–2093 μ g C m ‐2 in the mixed layer occurred in early and late spring, depending on the station. The large ciliate Laboea strobila was an important component of the microzooplankton biomass, and increased substantially at three out of the five stations between early and late spring. Strong upwelling in early summer resulted in substantial decreases in picophytoplankton and microzooplankton abundance. In late summer the composition of microzooplankton population had changed substantially, with the

Subtidal Galeolaria hystrix (Polychaeta: Serpulidae) reefs in Paterson Inlet, Stewart Island, New Zealand - Abigail M. Smith; Catherine R. McGourty; Louise Kregting; Andrew Elliot (New Zealand Journal of Marine and Freshwater Research, 2005)
Serpulid patch reefs of Galeolaria hystrix Mörch, 1863 were found in water depths of 9–16 m in Big Glory Bay, Paterson Inlet, Stewart Island, and here we report preliminary studies of these important habitat‐formers. This is the first observation of this species in subtidal patch reefs; 114 reefs were noted in a survey of 28 000 m 2 . Most reefs were 1–5 m in diameter, and up to 1.5 m high. Up to 65% of the serpulid tubes were occupied by living G. hystrix during a mid‐winter diving survey; 64% of reefs observed were whole, whereas 36% were broken or dead. Radiometric dating of a basal specimen of reef carbonate showed it to be less than 50 years old. Production of high‐Mg calcite, ranging from 9 to 11 wt% MgCO 3 , by G. hystrix may be as much as 11 kg CaCO 3 m ‐2 y ‐1 , but was not reflected in surrounding sediments, which were dominantly terrigenous muds. A rich reef fauna, both sessile and motile, was associated with the reefs. Further study of these unusual temperate reefs is strongly recommended.

Evaluation of two dipping methods for sampling immature Culex and Ochlerotatus mosquitoes (Diptera: Culicidae) from artificial containers - Paul T. Leisnham; David P. Slaney; Philip J. Lester; Philip Weinstein (New Zealand Journal of Marine and Freshwater Research, 2005)
Monitoring changes in populations of immature (larvae and pupae) mosquitoes are fundamental to determining mosquito‐borne disease risk. Dipping is the most common method used to sample immature mosquitoes, but it can be biased towards particular species and instars. We aimed to assess the generality of the findings of Mori (1989), who showed that stirring the water of artificial containers gave more consistent and accurate samples of Ochlerotatus togoi compared with conventional dipping without prior stirring. Five water‐filled artificial containers were placed in each of pastureland, urbanland, and native forest. These containers were subsequently colonised by Culex pervigilans and O. notoscriptus and were used to compare two dipping methods using a plastic dipper. One method involved removing the container from the field and stirring the water before sampling (destructive sampling), and was compared with a conventional field dipping method without prior stirring (field dipping). Results from this study showed that when comparing samples from the two methods, destructive sampling gave estimates that had very strong and better correlations with absolute counts, and were more accurate and consistent. Field dipping generally underestimated O. notoscriptus, possibly because it did not sample the bottom of the container where Ochlerotatus larvae browse detrital sediments. When using estimates from destructive sampling compared with field dipping, the relationship between mosquito density and land use was more similar to the relationship between absolute counts and land use across all population measures used. The results suggest that destructive sampling may be a more reliable mosquito sampling method than conventional field dipping when studying questions on mosquito ecology.

Direct impacts of commercial and recreational fishing on spiny lobster, Panulirus interruptus, populations at Santa Catalina Island, California, United States - Matthew Iacchei; Patrick Robinson; Kathy Ann Miller (New Zealand Journal of Marine and Freshwater Research, 2005)
The California spiny or red rock lobster, Panulirus interruptus, is an ecologically and economically important species that has been exploited since the 1800s. No previous study in California has assessed the impacts of the recreational or commercial lobster harvest. Before the 2003–04 commercial and recreational lobster seasons, we conducted a fishery‐independent trap survey at Santa Catalina Island to document the impact of the lobster fisheries on the size structure, abundance, and sex ratios of mature P. interruptus (>65 mm carapace length (CL)). We concurrently sampled a predominantly commercially fished area, a recreationally fished area, and a 23‐year‐old invertebrate no‐take (INT) reserve. Relative to the INT reserve, legal‐size lobsters in the recreational area were similar in CL, but 31% less abundant. Legal‐size lobsters in the commercial area were 8% smaller and 70% less abundant than those in the INT reserve. The sex ratio of legal‐size lobsters, although near 50:50 in the recreational and INT reserve areas, was male‐dominated (67:33) in the commercial area. Differences in CPUE and mean CL of sub‐legal lobsters in the recreational and commercial areas suggest that factors in addition to harvesting pressure may affect these populations. Total biomass of mature lobsters in the recreational and commercial areas was 92% and 45%, respectively, of biomass in the INT reserve. Fecundity in the recreational and commercial areas was 83% and 42%, respectively, of fecundity in the INT reserve. This study provides preliminary data for future ecological studies and fisheries management evaluations.

Climate change in contrasting river basins: adaptation strategies for water, food and environment. Edited by JAerts and PDroogers. Published in 2004 by CABI Publishing, 288 p., hardcover. ISBN: 0–85199–835–6. Price: US$100 (orders: services@dadirect.com.au).Australian water bugs. Their biology and identification (Hemiptera‐Heteroptera, Gerromorpha & Nepomorpha). By Nils MAndersen† and Tom AWeir. Published in 2004 by CSIRO Publishing/Apollo Books, P.O. Box 1139, Collingwood, VIC 3066, Australia. 344 p., hardcover. ISBN: 0–643–090517. Price: AU$135.00 (orders: publishing.sales@csiro.au).The Lakes Handbook. Volume I: Limnology and Limnetic Ecology. Volume II: Lake restoration and rehabilitation. Edited by PatrickO'Sullivan and ColinReynolds. Published by Blackwell Publishing Ltd., 109 Cowley Road, Oxford OX4 1JF, United Kingdom (http//www.blackwellpublishing.com). Volume I (published in 2003) 712 p., hardcover. ISBN: 0632047976. Price: £125. Volume II (published in 2004) 568 p., hardcover. ISBN: 063204795X. Price: £125. - Jim Renwick; Marie‐Claude Larivière; Ian Hawes (New Zealand Journal of Marine and Freshwater Research, 2005)

Revision of the genus Bdellamaris (Hirudinea: Piscicolidae) including a new combination, Bdellamaris manteri - Julianne Williams; Eugene Burreson (New Zealand Journal of Marine and Freshwater Research, 2005)
The New Zealand fish leech genus Bdellamaris was revised and a redescription of the type species, Bdellamaris eptatreti, was made using material from Eptatretus cirrhatus, the type host for B. eptatreti. Since the holotype has been lost and paratypes exist only in the form of frontal sections of approximately one third of a leech, a neotype was designated. Individuals in Bdellamaris lack eyes, ocelli, and conducting tissue and possess 11 pairs of pulsatile vesicles, 6 pairs of testisacs, accessory gland cells on the terminal portion of the male reproductive system, and a seminal receptacle. Bdellamaris eptatreti is characterised by a uniformly unpigmented body and suckers yielding a white overall appearance. Makarabdella manteri is transferred to the genus Bdellamaris after study of the type specimen and new material collected from the Chatham Rise, New Zealand. This species is characterised by its small size and by orange transverse pigment bands.

Decadal temperature changes in the Tasman Sea - Philip J.H. Sutton; Melissa Bowen; Dean Roemmich (New Zealand Journal of Marine and Freshwater Research, 2005)
Ocean temperature changes between 1991 and 2005 in the eastern Tasman Sea were analysed. This area was chosen because of a combination of data availability, low mesoscale variability and because of its importance in determining the climate of the downwind New Zealand landmass. A large warming extending to the full depth of the water column (c. 800 m) was found to have occurred between 1996 and 2002. This warming was seen in measurements by expendable bathythermographs and also in satellite sea surface temperature and sea surface height products, and has a clear impact on New Zealand's terrestrial temperature. The nature of the warming is discussed, together with likely forcing mechanisms. No local forcing mechanisms are consistent with the observed warming, leading to the conclusion that the signal seen in the Tasman Sea is part of a larger South Pacific‐wide phenomenon.

Gametogenic development and spawning of the razor clam, Zenatia acinaces in northeastern New Zealand - P. E. Gribben (New Zealand Journal of Marine and Freshwater Research, 2005)
The potential exists for New Zealand to exploit already established markets for razor clams through development of fisheries or aquaculture industries for the New Zealand razor clam, Zenatia acinaces. However, fishery or aquaculture development for Z. acinaces requires an understanding of the reproductive cycle including the timing of gametogenic development and spawning. The reproductive cycle of Z. acinaces was studied over an 11‐month period from May 2000 to March 2001 at Kennedy Bay, Coromandel Peninsula, using qualitative standard histological analysis and quantitative measures of oocytes. Histological analysis indicated that Z. acinaces is dioecious and gametogenic development was synchronous between the sexes. Gametogenesis began in June with gametes maturing quickly and by August/September (late winter/ early spring) most razor clams were ripe. Spawning began as early as September (spring) although spawning mainly occurred during October. By December (summer), nearly all clams were completely spent. From January 2001 most clams could not be sexed as all residual gametes were resorbed. Razor clams remained in this stage during March 2001. Spawning began when the water temperature was around its lowest, c. 15°C. Monthly mean number of eggs/follicle was sensitive to changes in reproductive development, closely following patterns observed in the qualitative stagings. Patterns of monthly mean oocyte diameters did not adequately describe the spawning events observed in qualitative analyses. Sex ratios were equal over the size range (69–99 mm shell length) of clams that could be sexed. The data presented in this study provide valuable information on the timing of spawning events for Z. acinaces, necessary for developing sustainable management strategies and selecting broodstock for aquaculture.

Evaluating local population dynamics of the American lobster, Homarus americanus, with trap‐based mark‐recapture methods and seabed mapping - Michael J. Dunnington; Richard A. Wahle; Michael C. Bell; Nathan R. Geraldi (New Zealand Journal of Marine and Freshwater Research, 2005)
Seabed mapping, spatially referenced trapping, and mark‐recapture methods have all been useful tools in ecological studies of lobsters and other benthic animals. Here we integrate the three methods to evaluate local population dynamics and movements of American lobsters, Homarus americanus, in coastal fishing grounds in Maine, United States. The study was conducted on five study areas of different size, and used two different sampling protocols. At one site (1 km 2 in area) we used a monthly mark‐recapture sampling interval over a 6‐month period, only tagging a subsample of the catch. At four smaller sites (0.3 km 2 ) we used a shorter‐term approach, sampling at 3–4‐day intervals for a 2‐week duration, tagging the entire catch. Tagging data were analysed with a modified Jolly‐Seber model adapted for continuous sampling to estimate population abundance, gains (immigration), and losses (emigration and mortality). Side‐scan sonar surveys of the seabed combined with diver‐based population surveys, stratified by substrate type, provided an independent comparison to mark‐recapture‐based estimates of abundance over the same areas. Spatial referencing of trap catch also allowed us to relate catch rates and lobster movements directly to seabed features. The longer‐term tagging data on the larger study area provided abundance estimates that were more consistent with the diver observations, and estimates of gains and losses statistically more robust, than those derived from the shorter‐term effort on the smaller sites. The flux of lobsters followed the well known seasonal movements on these fishing grounds, with gains and losses from the larger study area ranging over 1000 individuals per day, and an estimated mid‐summer peak density of >65 000 lobsters per km 2 (individuals >50 mm carapace length). This approach may lend itself to broader application with the American lobster.

Geographic and sex‐specific variation in growth of yellow‐eyed mullet, Aldrichetta forsteri, from estuaries around New Zealand - Thomas D. Curtis; Jeffrey S. Shima (New Zealand Journal of Marine and Freshwater Research, 2005)
Survival and reproductive rates in fish are often a function of body size. Consequently, spatial‐ and sex‐specific variation in somatic growth rates can have important consequences for population growth and resilience. We used otolith‐based approaches to estimate geographic‐ and sex‐specific growth rates of yellow‐eyed mullet ( Aldrichetta forsteri ) collected from 14 estuaries and harbours around New Zealand. Aldrichetta forsteri is an abundant and dominant component of New Zealand's estuarine fish fauna. We extracted otoliths from 511 fish, validated daily and annual increments, and prepared transverse thin sections of otoliths to determine age. “Size‐at‐age” relationships were estimated using both linear‐ and non‐linear (von Bertalanffy) growth models, and model performance was evaluated using Akaike's Information Criterion. Because growth rates of sampled fish were best approximated by linear functions, we used ANCOVA to test the null hypothesis that growth rates of A. forsteri were homogeneous between sexes and among geographic locations around New Zealand. Our analyses suggest heterogeneous growth rates between sexes and among locations. Interestingly, relative growth rates between sexes appeared to vary across separate latitudinal gradients for North Island and South Island. Within each island (but not across islands), female A. forsteri generally grew faster than males at the lowest latitudes; relative growth rates of females declined progressively below males with increasing latitude.

International accreditation of sandwich hybridisation assay format DNA probes for micro‐algae - Katie Ayers; Lesley L. Rhodes; John Tyrrell; Melissa Gladstone; Chris Scholin (New Zealand Journal of Marine and Freshwater Research, 2005)
The sandwich hybridisation assay (SHA) is a DNA probe‐based method for rapid identification and enumeration of toxic micro‐algae which uses species specific oligonucleotide probes targeted at ribosomal RNA. It is suited to fragile micro‐algal cells which commonly collapse during the fixation stage of sample collection, compromising identification by traditional microscopy. The assay has been available for research for several years, but was validated and accepted for international accreditation for commercial laboratory use in New Zealand in May 2004 (International Accreditation New Zealand: ISO 17025). During the validation of the raphidophyte assay, some discrepancies were noted between SHA cell concentration estimates and traditional light microscope cell counts. Higher SHA estimates were recorded when blooms had collapsed but rRNA was still present in sea water. Conversely, higher traditional cell counts occurred when sample delivery was delayed more than 48 h, presumably owing to degradation of rRNA in the live cultures used for the SHA. SHA cell concentration estimates of the toxic diatom bloom‐former Pseudo‐nitzschia australis were also compared with whole cell format DNA probe counts and traditional microscope counts; SHA counts were comparable for the three methods tested.

Impacts of mosquitofish, Gambusia affinis, on black mudfish, Neochanna diversus - Nicholas Ling; Kate Willis (New Zealand Journal of Marine and Freshwater Research, 2005)
The potential for western mosquitofish, Gambusia affinis, to negatively affect populations of black mudfish in New Zealand wetlands was investigated with annual fishing surveys of the Whangamarino wetland and by laboratory experiments evaluating competition and predation of mosquitofish on mudfish adults and larvae. Abundance of mudfish juveniles was reduced in the presence of mosquitofish at marginal wetland sites close to permanent water, but mosquitofish were not found at ephemeral adult mudfish habitats. In constructed wetland microcosms, mosquitofish reduced both growth and condition of post‐larval mudfish but did not attack or kill mudfish. In laboratory aquaria, mosquitofish rapidly consumed mudfish fry but survival time of the latter was significantly extended by an increase in density of submerged structures and by the presence of an alternative food source for mosquitofish. Because mosquitofish cannot survive in ephemeral wetlands that dry over summer, the impacts of mosquitofish on mudfish are likely to be minimal except in habitats where mosquitofish can survive year‐round owing to the presence of permanent standing water.

Sediment remobilisation from decomposing cordgrass ( Spartina anglica ) patches on a wave‐exposed intertidal flat - Andrew Swales; Ron Ovenden; Iain T. MacDonald; Andrew M. Lohrer; Karen L. Burt (New Zealand Journal of Marine and Freshwater Research, 2005)
Concerns about the potential adverse effects of Spartina invasion on New Zealand estuaries, such as habitat loss and degradation, have led to herbicide use to control its spread. An experiment was conducted in the Manukau Harbour (New Zealand) to determine sediment remobilisation rates (? E ) from herbicide‐treated S. anglica patches. Paired treatment and control patches (≤25 m diam.) were monitored at two sites 500 m apart with different wave exposures. Above‐ (AGB) and below‐ground (BGB) biomass decomposition and AE were determined from repeat surveys over c. 2.5 years. Work done by waves ( W ) , which integrates wave‐energy dissipation at the bed over time, was used as a surrogate measure of sediment transport potential. Complete AGB loss occurred in both treated patches within 3 months of initial herbicide application, whereas BGB (a matrix of roots and rhizomes) persisted much longer. An exponential decay model ( r 2 = 0.6) fitted to the site‐two treatment data predicted an c. 85% reduction in BGB after 5 years, whereas the BGB changes for the larger and more heterogeneous site‐one treatment were more complex. BGB was a better predictor of average bed elevation than AGB in multiple regression models and, although bed elevation decreased through time and with waves, BGB was positively related to bed elevation at both sites. AE was similar for both treatment patches (c. 0.05 and c. 0.06 m yr ‐1 , P 0.001, r 2 ≥ 0.97) and complete sediment loss was predicted to occur within 6–10 years. The site‐one control patch accumulated sediment (0.01 m yr ‐1 , P 0.001, r 2 = 0.81) whereas the more wave‐exposed site‐two control eroded (0.01 m yr ‐1 , P = 0.0017, r 2 = 0.61). The potential for adverse sediment effects resulting from Spartina control at wave‐exposed sites will be minimal if the treated areas are small relative to the size of the estuary.

Sodium fluoroacetate (1080) residues in longfin eels, Anguilla dieffenbachii, following exposure to contaminated water and food - P.O'B. Lyver; J. Ataria; K. Trought; P. Fisher (New Zealand Journal of Marine and Freshwater Research, 2005)
Captive longfin eels ( Anguilla dieffenbachii ) were exposed to the vertebrate pesticide sodium fluoroacetate (1080) in the water column and through the ingestion of cereal pellet baits or possum muscle and gut tissue that contained 1080 residue. No mortality or unusual behaviour (in comparison with the controls) occurred in eels that were exposed to 1080. However, significantly greater weight loss occurred in eels exposed to 1080 compared with those eels that were not. No residue was detected in tissues of eels exposed to 1080 cereal baits through ingestion and direct (dermal and respiratory) absorption, or through direct absorption only. Low concentrations of 1080 were detected in muscle tissue of eels that consumed contaminated possum muscle (x = 0.0174 μg/g) or gut (x = 0.0306 μg/g) tissue. The primary factors affecting the concentration of 1080 detected in eel tissue included the dose of 1080 (mg/kg) that each eel received and number of days since the eel last fed on contaminated tissue. Based on the 1080 concentrations measured in eels in this study, the risk of acute poisoning to humans from eating contaminated eel flesh is considered extremely low. Even so, national and international perceptions and food safety standards have the potential to limit eel exports and/or close an eel fishery if 1080 residue was discovered in tissue.

Physical characterisation and a biologically focused classification of “seamounts” in the New Zealand region - A. A. Rowden; M. R. Clark; I. C. Wright (New Zealand Journal of Marine and Freshwater Research, 2005)
The physical, biological, and oceano‐graphic characteristics of seamounts of the New Zealand region of the South Pacific Ocean are poorly known. The aim of this study was to present a synopsis of the physical characteristics of seamounts within the region, and to present a preliminary classification using biologically meaningful variables. Data for up to 16 environmental variables were collated and used to describe the distribution and characteristics of the c. 800 known seamounts in the New Zealand region. Seamounts span a wide range of sizes, depths, elevation, geological associations and origins, and occur over the latitudinal range of the region, lying in different water masses of varying productivity, and both near shore and off shore. As such, it was difficult to generally describe New Zealand seamounts, as there is no “typical” feature. Thirteen environmental variables were included in a multivariate cluster analysis to identify 12 seamount similarity groupings, for a subset of over half the known seamounts. The groupings generally displayed an appreciable geographic distribution throughout the region, and were largely characterised by a combination of four variables (depth at peak, depth at base, elevation, and distance from continental shelf). In the future, the findings of the present study can be tested to determine the validity and usefulness of the approach for directing future biodiversity research and informing management of seamount habitat.

Development of a regional ocean model for New Zealand - G. J. Rickard; M. G. Hadfield; M. J. Roberts (New Zealand Journal of Marine and Freshwater Research, 2005)
A regional ocean model with a horizontal resolution of 1/6° encompassing the New Zealand Exclusive Economic Zone is described. The regional model successfully downscaled solutions from a high resolution, global, coupled model HadCEM. Transport estimates from the global and regional models were compared with observations, and both models supported largely consistent, climatological mean solutions. The regional model used monthly mean forcing at the surface. Nevertheless, the regional model eddy kinetic energy (EKE) spatial patterns compared favourably with long‐term mean satellite altimetric estimates, although the modelled background EKE amplitudes were much lower than observed. A series of permanent eddies associated with the western boundary current system around the top of the North Island of New Zealand were reproduced, and an eddy adjacent to Norfolk Ridge was identified in both the global and regional models. The western boundary current system around the North Island of New Zealand and the associated eddies were the most sensitive components of the model solutions, being influenced by initial conditions, wind forcing, and the model domain size.

The effects of spatial targeting of fishing effort on the distribution of the Norway lobster, Nephrops norvegicus, on the Farn Deeps grounds, northeast England - Michael C. Bell; Jon M. Elson; Julian T Addison (New Zealand Journal of Marine and Freshwater Research, 2005)
Nephrops norvegicus is an essentially sedentary species of lobster that forms the basis of valuable fisheries in the northwest Atlantic and western Mediterranean. Fishers exploiting a sedentary stock are likely to visit the most profitable (highest catch rate) areas first. Such spatial targeting of fishing effort is likely to have important consequences for stock monitoring and assessment. We used underwater television surveys of Nephrops burrow densities on the Farn Deeps grounds, northeast England, to describe changes in abundance and distribution between the beginning and end of a winter fishing season. Above a threshold of c. 0.6 burrows m –2 , overwinter depletion increased with burrow density, consistent with fishing effort being targeted at the highest densities. A simple simulation model showed that this pattern of mortality is an expected consequence of spatially targeted fishing behaviour. The model also predicted that there is decreased spatial variability in density after fishing. An overall decrease in variability was not evident from the survey data, but geostatistical analysis indicated that there was “flattening” of the density profile along a north‐south axis, consistent with the dominant direction of commercial trawling. We concluded that Nephrops fishers are able to find and exploit the highest densities of their target species. A potential consequence is that catch per unit effort (CPUE) data used to monitor trends in this stock potentially could mask declines in stock abundance. CPUE might be more effective if analysed at finer spatial scales, but this is not currently possible. In the absence of these fine scale commercial data, fishery‐independent surveys (e.g., underwater television) are an important source of information on trends in stock abundance.

Comment: American Fisheries Society makes changes in the end - R.M. McDowall (New Zealand Journal of Marine and Freshwater Research, 2005)

Evidence of a significant wind‐driven circulation in Akaroa Harbour. Part 2: Results from the application of a width averaged hydrodynamic numerical model (CE‐QUAL‐W2) - Darlene N. Heuff; Robert H. Spigel; Alex H. Ross (New Zealand Journal of Marine and Freshwater Research, 2005)
Results from the application of the two‐dimensional, laterally‐averaged hydrodynamic model, CE‐QUAL‐W2 to Akaroa Harbour, New Zealand were compared with 3 months of temperature and current data to investigate the connection between significant wind‐driven circulation and vertical mixing. Results indicate that in general, CE‐QUAL‐W2 reproduced realistic values for width‐averaged along‐Harbour current speeds and water column temperature structure. However, during periods of strong winds, the mixed layer depth was predicted to be shallower than observed; c. one‐third as compared to c. one‐half. Simulations of tidally‐driven flow highlighted the restrictions of the two‐dimensionality imposed by the model, though this type of flow was not found to result in appreciable mixing of the water column. Data from an independent field survey supported the validity of the use of CE‐QUAL‐W2 under (at least) light‐to‐moderate sea‐breeze conditions.

Effects of small ponds on stream water quality and macroinvertebrate communities - John R. Maxted; Colin H. McCready; Mike R. Scarsbrook (New Zealand Journal of Marine and Freshwater Research, 2005)
Six small constructed ponds (surface area 500–7500 m 2 , catchment area 28–158 ha) in rural and native forest catchments in the Auckland region had poorer water quality than the streams they replaced. Temperature (24°C) and dissolved oxygen (DO) (4 mg/litre) criteria were exceeded for up to 46% and 84% of days, respectively, during a critical 40‐day summer period. The poor conditions found in ponds, even within undeveloped native forest catchments, indicated that the physical characteristics of ponds (e.g., lack of shade, organic sediments) affected water quality independently of other factors (e.g., land use, riparian protection). The frequency and severity of the exceedences were related to pond size, retention time, and catchment land use; the most degraded conditions were found in rural ponds with largest surface areas and longest retention times. Ponds affected water quality and macroinvertebrate communities downstream. Exceedences of temperature and DO criteria occurred more frequently and were more severe downstream than upstream of ponds. Ponds in rural catchments increased mean daily stream temperatures 3.1–6.6°C during the critical summer period, and temperature differences were three times higher than those in bush catchments (0.8–2.0°C). Elevated temperatures were observed for hundreds of metres downstream owing to the slow rate of cooling (1°C/ 100 m), expanding the extent of adverse effects well beyond the “footprint” of the pond. Macroinvertebrate community composition (sample area 1–3 m 2 ) and values of four commonly used metrics appeared to be significantly affected by ponds in rural and native forest catchments. These finding have important management implications that should lead to modifications (e.g., breaching dams) of the estimated 4500 existing ponds in the Auckland region, where possible, and restrictions on proposals for new “on‐line” ponds.

Size trends and population characteristics of striped marlin, Tetrapturus audax caught in the New Zealand recreational fishery - R. K. Kopf; P. S. Davie; J. C. Holdsworth (New Zealand Journal of Marine and Freshwater Research, 2005)
Size trends and population characteristics of striped marlin, Tetrapturus audax, caught in the New Zealand recreational fishery were evaluated using club records from the Bay of Islands Sword‐fish Club (BOISC) from 1925 to 2003 (n = 15 114) and biological samples from northern New Zealand collected from 1985 to 1994 (n = 684). Average weight (kg) ± SE of striped marlin declined 6–9 kg every 20 years between 1925 (124.2 ± 1.0 kg) and 2003 (100.1 kg ± 0.4). Weight (H 14843 = 444.58, P 0.001) and condition (H 443 = 37.54, P 0.001) increased significantly throughout the recreational fishing season (December‐May). No differences were observed in the lower jaw‐fork length (LJFL)‐weight (W) relationship between sexes or years but average weight of females (106.2 ±1.1 kg) was significantly greater than males (90.2 ±1.2 kg) from 1985 to 1994 (F 684 = 88.37, P 0.001). Negative allometric growth (W = 2E ‐08 LJFL 2.88 ) was recorded for all striped marlin. Individual growth was modelled by fitting backcalculated LJFL to eight age classes derived from dorsal spine measurements (n = 94) using the von Bertalanffy growth equation (r 2 = 0.96). The parameters estimated in the von Bertalanffy growth equation were asymptotic length (L ) = 3010 mm, annual growth rate (K) = 0.22, age (yr) at hypothetical length 0 (t 0 ) = ‐0.04.

New records and invasive potential of the poeciliid fish Phalloceros caudimaculatus - J. J. L. Rowley; T. S. Rayner; G. H. Pyke (New Zealand Journal of Marine and Freshwater Research, 2005)
Many species from the family Poeciliidae have been transported around the world by the aquarium trade, often establishing populations in areas far outside their natural range. The one‐spot livebearer, Phalloceros caudimaculatus is one such poeciliid species. In March 2002, a nonindigenous population of P. caudimaculatus was discovered at Collaroy, in the Sydney metropolitan area, the first record of this species in eastern Australia. Following this discovery, electrofishing and light‐trap surveys were conducted at the site, and dip‐netting and visual surveys were conducted in surrounding water bodies. P. caudimaculatus was widespread and abundant at the Collaroy site, but no further populations were discovered. Another pest poeciliid species, Gambusia holbrooki, originally present at the site, was absent and, although the mechanism remains unclear, may have been displaced by P. caudimaculatus. Both P. caudimaculatus and G. holbrooki share the characteristics of successful invasive species, with extremely broad physical tolerances and high reproductive outputs. Given the well‐documented negative ecological effects of poeciliids, especially G. holbrooki, we recommend that a precautionary approach should be adopted for the management of P. caudimaculatus and its eradication from the site be attempted.

Batch fecundity and spawning frequency of southern blue whiting (Micromesistius australis) in the southwest Atlantic Ocean - G. J. Macchi; M. Pájaro; O.C. Wöhler; M. J. Acevedo; R. L. Centurión; D. G. Urteaga (New Zealand Journal of Marine and Freshwater Research, 2005)
The reproductive biology of southern blue whiting (Micromesistius australis) inhabiting waters of the southwest Atlantic Ocean (52°‐53°S and 57°‐62°W) was studied through histological analysis of the ovaries. During 2003, the spawning peak occurred at the beginning of September south of the Malvinas Islands. Batch fecundity of this species ranged from 35 000 (41 cm total length, TL) to 245 000 (62 cm TL) oocytes and relative batch fecundity was 122 ± 43 (Mean ± SD, n = 24) oocytes per gram somatic weight. The average proportion of mature females with stage‐0 post‐ovulatory follicles was 0.25 for September 2003, which indicated a spawning frequency of 4 days during the peak of the season. Large females produced more egg batches than small spawners during the same period, but no significant relationship was found between oocyte dry weight and female size of southern blue whiting.

Predicting survival of western rock lobsters Panulirus cygnus using discriminant analysis of haemolymph parameters taken immediately following simulated handling treatments - B. D. Paterson; P. T. Spanoghe; G. W. Davidson; W. Hosking; S. Nottingham; J. Jussila; L. H. Evans (New Zealand Journal of Marine and Freshwater Research, 2005)
Instances of morbidity amongst rock lobsters (Panulirus cygnus) arriving at factories in Western Australia (WA) have been attributed to stress during post‐harvest handling. This study used discriminant analysis to determine whether physiological correlates of stress following a period of simulated post‐harvest handling had any validity as predictors of future rejection or morbidity of western rock lobsters. Groups of 230 western rock lobsters were stored for 6 h in five environments (submerged/flowing sea water, submerged/recirculating sea water, humid air, flowing seawater spray, and recirculated seawater spray). The experiment was conducted in late spring (ambient sea water 22°C), and repeated again in early autumn (ambient sea water 26°C). After 6 h treatment, each lobster was graded for acceptability for live export, numbered, and its haemolymph was sampled. The samples were analysed for a number of physiological and health status parameters. The lobsters were then stored for a week in tanks in the live lobster factory to record mortality. The mortality of lobsters in the factory was associated with earlier deviations in haemolymph parameters as they emerged from the storage treatments. Discriminant analysis (DA) of the haemolymph assays enabled the fate of 80–90% of the lobsters to be correctly categorised within each experiment. However, functions derived from one experiment were less accurate at predicting mortality when applied to the other experiments. One of the reasons for this was the higher mortality and the more severe patho‐physiological changes observed in lobsters stored in humid air or sprays at the higher temperature. The analysis identified lactate accumulation during emersion and associated physiological and haemocyte‐related effects as a major correlate of mortality. Reducing these deviations, for example by submerged transport, is expected to ensure high levels of survival. None of the indicators tested predicted mortality with total accuracy. The simplest and most accurate means of comparing emersed treatments was to count the mortality afterwards.

Microscopic examination of acidic hot springs of Waiotapu, North Island, New Zealand - Dean G. Ellis; Richard L. Weiss Bizzoco; Yukari Maezato; Judith N. Baggett; Scott T. Kelley (New Zealand Journal of Marine and Freshwater Research, 2005)
Microorganisms other than Sulfolobus are reported for the first time in the low pH high temperature springs of Waiotapu, North Island, New Zealand. In one spring of the tourist reserve, rod‐shaped organisms with a toga‐like wall were observed, in addition to Sulfolobus‐like spheres. In another acid hot spring, microbial cells were small and intermingled with mineral crystals, making their presence difficult to detect, even by scanning electron microscopy (SEM). Evidence for the existence of microorganisms included: (1) phase contrast microscopic observation; (2) DNA‐specific staining with UV microscopy; and (3) SEM examination of natural samples. At pH 2, the highest temperature at which microbes were observed was 77°C and at pH 4.5, it was 87°C. Cells at pH 2, 77°C were small rods encrusted with mineral crystals shown by X‐ray microanalysis to consist mainly of silicon and aluminum. At pH 4.5, spherical, rod‐shaped, and filamentous cells were seen. Attempts to culture the observed microbes were unsuccessful. PCR, cloning, sequencing, and BLAST analysis identified Thermofilum pendens in Champagne Pool, and Sulfobacillus, Thiobacillus, and several unknown bacteria in Frying Pan Flat pools.

Marine decapod Crustacea of southern Australia: a guide to identification. By Gary C. B.Poore. Published in 2004 by CSIRO Publishing, P.O. Box 1139, Collingwood, VIC 3066, Australia. 608 p., hardcover. ISBN: 0–643–06906–2. Price: AU$180.00 (orders: publishing.sales@csiro.au).Marine mammals: fisheries, tourism and management issues. Edited by Nicholas J.Gales, Mark A.Hindell and RogerKirkwood. Published in 2003 by CSIRO Publishing, P.O. Box 1139, Collingwood, VIC 3066, Australia. 446 p., hardcover. ISBN: 0–643–06953–4. Price: AU$116 (orders: publishing.sales@csiro.au).Freshwater fishes of north‐eastern Australia. By BradPusey, MarkKennard, and AngelaArthington. Published in 2004 by CSIRO Publishing, P.O. Box 1139, Collingwood, VIC 3066, Australia. 700 p., hardcover. ISBN: 0–643–06966–6. Price: au$89.00 (orders: publishing.sales@csiro.au). - Graham D. Fenwick; Chris Lalas; R. M. McDowall (New Zealand Journal of Marine and Freshwater Research, 2005)

Evidence of a significant wind‐driven circulation in Akaroa Harbour. Part 1: Data obtained during the September‐November, 1998 field survey - Darlene N. Heuff; Robert H. Spigel; Alex H. Ross (New Zealand Journal of Marine and Freshwater Research, 2005)
Part 1 (P1) of a two‐part study of Akaroa Harbour, Bank's Peninsula, New Zealand, presents observational evidence of the development of a significant wind‐driven circulation in association with strong northerly and southerly wind events. These are common throughout the year though during the 3‐month field campaign (during the Southern Hemisphere spring of 1998) northerly wind events dominated. This wind‐driven circulation resulted in the weakening of density stratification within the Harbour, mixing the water column to depth over a significant portion of the study area.

Relative sensitivities of common freshwater fish and invertebrates to acute hypoxia - Michael J. Landman; Michael R. Van Den Heuvel; Nicholas Ling (New Zealand Journal of Marine and Freshwater Research, 2005)
The acute lethality of low dissolved oxygen (DO) was examined in laboratory studies using several New Zealand freshwater fish and two invertebrates at 15°C. The 48‐h LC50 value was used as the endpoint for acute DO sensitivity as, owing to rapid mortality, this was found to best approximate the threshold lethal concentration. Median lethal time to death did not provide a reliable endpoint for comparing sensitivities. Fish LC 50 values varied from 0.54 to 2.65 mg litre ‐1 , with inanga whitebait (Galaxias maculatus; 2.65 ± 0.19 mg litre ‐1 , mean + SEM) being the most sensitive species tested. Common smelt (Retropinna retropinna; 1.83 ± 0.08 mg litre –1 ) and rainbow trout (Oncorhynchus mykiss; 1.61 ± 0.06 mg litre –1 ) were similar in their sensitivities, whereas common bully (Gobiomorphus cotidianus; 0.91 ± 0.06 mg litre –1 ) and shortfin eel elvers (Anguilla australis; 0.54 ± 0.03 mg litre –1 ) were the most tolerant fish. The shrimp (Paratya curvirostris; 0.82 ± 0.09 mg litre –1 ) and freshwater crayfish (Koura, Paranephrops planifrons; 0.77 ± 0.06 mg litre –1 ) were also tolerant to low DO. A subset of experiments to determine the relative sensitivities of larval and juvenile trout and bully indicated no significant differences between these life stages.

Reproductive cycle, size at first maturation and fecundity in the golden ling, Genypterus blacodes, in Chile - Felipe Paredes; Ricardo Bravo (New Zealand Journal of Marine and Freshwater Research, 2005)
Reproductive aspects of the golden ling, Genypterus blacodes, from the southern Chilean fishery are presented. Gonad samples were obtained from commercially caught fish between September 1999 and October 2000. Stage of sexual maturity, gonadosomatic index (GSI), and size of females at 50% maturation determined by logistic methods and by plotting the mean GSI by total length, are presented for both years. Batch fecundity was calculated from subsampling mature ovaries containing oocytes in advanced stages of maturity. Changes in GSI and monthly diameters of oocytes showed that ling had a spawning season which extended between August and November. The sizes at first maturity in 1999 and 2000 were 86.6 and 84.8 cm total length (TL), respectively, using the logistic model, and 84 cm for both years using the mean GSI‐size plotting method. The mean batch fecundity was 333 330 oocytes per individual for fish sized 85–120 cm TL. Fecundity increased with increasing weight and total length.

Distribution of mid‐ and late‐stage Jasus edwardsii phyllosomas: Implications for larval recruitment processes - Stephen M. Chiswell; John D. Booth (New Zealand Journal of Marine and Freshwater Research, 2005)
The relative distributions of mid‐ and late‐stage phyllosomas, and pueruli, of Jasus edwardsii from five research cruises off the east coast of the North Island of New Zealand were analysed. A statistical approach was taken, using a bootstrapping with replacement method to test whether the observed mid‐ and late‐stage phyllosomas could have come from the same distribution. Differences in distribution between mid‐ and late‐stage phyllosomas were very close to significant at 95% confidence for two cruises, significant at 85% confidence for one cruise, and two cruises showed a non‐significant result. When all cruise data were combined into one analysis, the differences between mid‐ and late‐stage phyllosomas were significant with 85% confidence. On average, late‐stage phyllosomas were found 49 km further inshore than mid‐stage phyllosomas. One station during one cruise and one transect during another showed such high abundances that they affected the analyses. When these outlier data were excluded, the differences in mid‐and late‐stage distributions become significant with 99% confidence. One explanation for observed distribution differences is that the late‐stage phyllosomas swim shoreward—as the pueruli are believed to do. This implies an ability to navigate in both these early life forms. If the late‐stage larvae are indeed swimming horizontally, it is likely that this is most effectively accomplished by final‐stage phyllosomas, which have well developed pleopods, similar to those in the puerulus stage.

Distribution and abundance of recruits of the eastern rock lobster ( Jasus verreauxi ) along the coast of New South Wales, Australia - S. S. Montgomery; J. R. Craig (New Zealand Journal of Marine and Freshwater Research, 2005)
In the mid 1990s, the New South Wales government introduced management measures to increase the size of the population of the eastern rock (spiny) lobster, Jasus verreauxi. A fully orthogonal sampling design was begun in July 1995 to test, amongst others, the hypothesis that the relative abundance of recruits (stages of peuruli to early juveniles combined) to the eastern rock lobster population will change over space and time. In the design for the full sampling strategy were the factors of Year (eight levels) and Location (four levels). Three replicate collectors at each of three sites at each location were sampled during the first quarter of each lunar month between August and January between 1995–96 and 2002–03 (inclusive). Recruits occurred on collectors between September and January each year. Results of the two‐factor ANOVA showed a significant interaction between Year and Location, meaning that differences in mean relative abundance of recruits between years will depend upon the location. Comparison of means (SNK test) show that in each year the relative abundance of recruits was greatest at the southern locations, but no pattern in mean relative abundance between years for each location was apparent. Management measures introduced in the mid 1990s to increase population size have not to date resulted in increasing levels of recruitment. Considering this, levels of recruitment to the population appear to be influenced most by variation in environmental factors rather than levels of egg production from the stock.

An early Paleogene sponge fauna, Chatham Island, New Zealand - Michelle Kelly; John S. Buckeridge (New Zealand Journal of Marine and Freshwater Research, 2005)
A late Paleocene‐early Eocene (c. 60–53 Ma) poriferan fauna, comprising hexactinellids (Class Hexactinellida), astrophorids (Class Demospongiae: Family Astrophorida), and lithistids (“lithistid” Demospongiae) has been identified from the Tutuiri Greensand outcropping on the north coast of Chatham Island, New Zealand. Most of the fossils are hexactinellids, comprising extremely delicate siliceous networks embedded in friable sandstone. The sediment matrix within and around these skeletons contains numerous siliceous demosponge spicules, many of which are exceptionally well preserved. The soft friable matrix of the Tutuiri Greensand has made extraction a relatively simple process, making taxonomic identification of the material, and comparison with adjacent Recent and other New Zealand Eocene faunas possible. These sponge body fossils and spicule microfossils indicate a fauna that was once dominated by hexactinellids, lithistid, and astrophorid demosponges. A qualitative comparison of the abundance and diversity of the Tutuiri Greensand sponge fauna with the present‐day Chatham Rise sponge fauna indicates that the late Paleocene‐early Eocene fauna is as diverse as the Recent fauna, for the hexactinellid sponges and astrophorid demosponges, and much more diverse for lithistid sponges. The paleoecology of the Tutuiri Greensand has been interpreted as inner to mid shelf water depths (50–250 m) but the poriferan fauna described here is more like that of the present‐day soft sediment benthic environment of the Chatham Rise at 800–1200 m.

Visual assessment of the reproductive condition of female western rock lobsters ( Panulirus cygnus ) - Roy Melville‐Smith; Simon de Lestang (New Zealand Journal of Marine and Freshwater Research, 2005)
An important issue when surveying the reproductive condition of large numbers of female Panulirus cygnus in the field is that each animal must be assessed quickly and accurately on the basis of only a few easily discernable criteria. The four biological criteria most commonly recorded for each lobster are: (1) ovigerous setae condition (not present, partially developed, and fully developed); (2) the presence (unused or eroded) of a spermato‐phore mass; (3) the presence and developmental stage of external ova; and (4) the visual appearance of the ovaries through the dorso‐thoracic musculature. Using the above criteria each female can then be assigned to a reproductive state, i.e., immature, inactive breeder, single breeder, or double breeder. This study compared external assessments with internal cellular development of the ovary (via histology) and elucidated the shortcomings of the external technique. This has resulted in the production of a modified set of criteria that, if applied to samples collected during the peak of the breeding season, enables the breeding state of a female western rock lobster to be more accurately determined in the field without causing it any damage. The height of the breeding season is the optimum time for stock egg production assessment.

Distribution, abundance and growth of New Zealand sea lion Phocarctos hookeri pups on Campbell Island - Simon Childerhouse; Nadine Gibbs; Gus McAlister; Shaun McConkey; Helen McConnell; Nathan McNally; David Sutherland (New Zealand Journal of Marine and Freshwater Research, 2005)
Nine weeks field work was completed during two trips in January/February and March/ April 2003 to investigate the distribution and abundance of New Zealand sea lion Phocarctos hookeri pups at Campbell Island. A total of 161 pups were tagged and a further 138 dead pups were found. A closed mark‐recapture model was used to estimate the total number of live pups (e.g., tagged plus untagged pups) at Campbell Island in April as 247 (SE = 28, 95% CI 198–308). Pup production at Campbell Island is estimated at 385, which comprises 13% of the total pup production for the species in the 2003 season. This is the first robust estimate of pup production for New Zealand sea lions at Campbell Island. The figure of 385 pups is considerably higher than any of the previous estimates reported from Campbell Island. The high level of pup mortality (36%) at Campbell Island for approximately the first 2 months after birth is higher than the 17% reported for the Auckland Islands for approximately the same period in 2003, but is similar to unusually high levels of mortality (20–30%) reported at the Auckland Islands in recent years. It was not possible to determine the cause of death of the 138 dead pups owing to scavenging and decomposition. Pups were found over the whole Island, with the exception of its northern end. Male pups were significantly heavier and faster growing than female pups over the same period.

Changes in verte brate‐type steroids and 5‐hydroxytryptamine during ovarian recrudescence in the Indian spiny lobster, Panulirus homarus - Ramalingam Kirubagaran; Dassiah M. Peter; Gopal Dharani; Nambali V. Vinithkumar; Gopinathapillai Sreeraj; Muthukamatchi Ravindran (New Zealand Journal of Marine and Freshwater Research, 2005)
Vertebrate‐type steroids (estradiol‐17β and progesterone) and 5‐hydroxytryptamine (5‐HT) were examined during the different stages of ovarian maturation in the Indian spiny lobster Panulirus homarus. Estradiol‐17β and progesterone in the haemolymph and ovary were quantified by radioim‐munoassay. Estradiol‐17β was not detectable in the haemolymph when the oocytes were in stage I. It appeared in the haemolymph only as the oocytes attained stage II. Subsequently, a sharp increase in the level of estradiol‐17β was observed in the haemolymph of lobsters with stage III oocytes; it then showed a significant fall when the ovary was full of stage IV oocytes. Although progesterone was also not detectable in the haemolymph when the oocytes were in stage I, it gradually increased during stages II and III and reached a peak level during stage IV. Surprisingly, both estradiol‐17β and progesterone were detectable in the ovary from stage I onwards. In the ovary, estradiol‐17β and progesterone showed peak levels during stages III and IV, respectively. A stage‐dependent change in the activity and distribution of 5‐hydroxytryptaminergic neurons in the brain and thoracic ganglia was also observed immunocytochemically in relation to ovarian recrudescence. Furthermore, HPLC‐EC conducted on the level of 5‐HT in the brain and thoracic ganglia indicated similar changes in relation to ovarian maturation. These results strongly suggest that 5‐HT is involved in ovarian development through certain inhibitory/stimulatory factors present in the X‐organ‐sinus gland complex of the eye‐stalk in the spiny lobster P. homarus.

Review - R. W. George (New Zealand Journal of Marine and Freshwater Research, 2005)
A comparison of the documented ecology and behaviour of the separate phases in the life cycles is presented. Data gathered during the review show that during the evolution of the family from deeper‐water habitats to the more rapidly fluctuating shallower waters, there have been many biological adjustments at each phase in their life cycles. In the more ancient Stridentes genera, like Puerulus, the larvae are found well below the surface waters and the pueruli often settle at greater depths than those of the adults. Long incubation times, few larval instars, and year‐round spawning are probably their life cycle characteristics. As an “intermediate‐evolved” genus of Stridentes, Palinurus lives along the outer shelf, grows slowly, matures late, and breeds seasonally once a year. Incubation time is long, the larvae live at depth, the number of larval instars is limited, and the puerulus is a weak swimmer. Settlement is often downstream of the breeding stock. Incubation times are short for the more recently evolved Stridentes Panulirus, the larvae pass through many instars in the surface waters to c. 200 m. Some pueruli settle in special coastal habitats, others settle in the same habitat as the adult. Breeding in the cooler water First Major Lineage species is seasonal, one or two broods being produced. Most of the species in the tropical Second Major Lineage are faster growing, breed repetitively over a long breeding season, and have a shorter larval life. For the Silentes, the trend in biological changes from deep to shallower water is comparable with that of Stridentes. Incubation is probably long in the more ancient Projasus, the larvae are rare in surface waters and the pueruli settle at depths similar to those of the adults. Sagmariasus and Jasus breed once during a defined season, incubation time is moderate, and the larvae pass through many instars. The pueruli of Sagmariasus settle downstream and exhibit contranatant migration whereas the pueruli of Jasus swim strongly to their shallow habitats. In each life cycle phase, migration methods range from vertical paddling in phyllosomata, horizontal swimming in pueruli, and horizontal walking when juveniles move to adult habitats. Adult movements are associated with foraging, searching for shelter, avoiding adverse seasonal conditions, or walking to preferred offshore locations for moulting and reproduction.

New species of benthopelagic copepod Xantharus (Calanoida: Scolecitrichidae) from the upper slope, eastern central New Zealand - Janet M. Bradford‐Grieve (New Zealand Journal of Marine and Freshwater Research, 2005)
Xantharus Andronov, 1981 is reported, for the first time from New Zealand, from the upper slope (306 m) off the southeastern coast of North Island (41°04.10′S, 176°22.05′E). Xantharus cryeri n. sp. females differ from the three known species by a combination of characters: antennules that extend to the distal border of pedigerous somite 2; ancestral segment XVIII of the antennule with 1 seta; mandible basis with 3 setae; maxilla endite 1 with 5 setae; leg 1 basis with inner distal border lined with small spinules; and leg 5 is squat, with all segments as long as wide and the 2 terminal spine‐like extensions of the terminal segment approximately as long as the articulated, inner, subterminal spine.

Field estimation of daily ration of Norway lobster ( Nephrops norvegicus ) in the south of Portugal - Margarida Cristo; Margarida Castro (New Zealand Journal of Marine and Freshwater Research, 2005)
Daily ration estimates of Norway lobster ( Nephrops norvegicus ) from field samplings over a 24‐h cycle were obtained. Four tows were conducted in the middle continental slope, off the south coast of Portugal. The results from Eggers (1977, 1979) and Elliot & Persson (1978) daily ration models were compared, by the Worobec 8‐method (1984), showing no significant differences among them. The estimates of food consumption obtained varied from 1.098 to 1.170 g dry food per 100 g body wet weight in males and 1.642 to 1.755 g dry food per 100 g body wet weight in females. Our results were compared with daily rations reported for other crustaceans. Daily ration values were compared and tested by a two‐way ANOVA, with interaction, showing significant differences between sexes. This has been registered for other decapods and may be explained by a period of active growth in females, on the onset of vitellogenesis, increasing their nutritional/ feeding needs.

Comparison of catches on two types of collector of recently settled stages of the spiny lobster ( Panulirus argus ) , Florida, United States - B. F. Phillips; Y. W. Cheng; C. Cox; J. Hunt; N. K. Jue; R. Melville‐Smith (New Zealand Journal of Marine and Freshwater Research, 2005)
This study compared catches of Panulirus argus pueruli and very young juveniles between Hunt and Sandwich collectors at Long and Big Munson Keys, Florida, United States. Catch comparisons were made over the peak puerulus settlement period between February and July 2002, using six Sandwich and six Hunt collectors at each site. The collectors were set out in arrays and the relative positions of the two collector types were reversed each month after they had been checked and the catch removed. A total of 3470 pueruli and juveniles were collected; 2011 and 1459 by Sandwich and Hunt collectors, respectively. Sandwich collectors caught an average of 5.43 more pueruli and juveniles per check than Hunt collectors, with this difference being significant for catches of clear pueruli (P1s), pigmented pueruli (P3s), and juvenile stages (J1s and J2s) ( P 0.05), but not for catches of semi‐pigmented pueruli (P2s). The catches made by both collector types were highly dependant on the month of collection and site of the collectors ( P 0.01). Catches were generally not influenced by the location of the collector in the array ( P = 0.50), but corner collectors caught significantly fewer P1s, P2s, P3s, and J1s and J2s than all other collectors ( P 0.01). Conditioning time influenced the total catch ( P 0.01) but was not significant for all individual P1s, P2s, P3s, and J1s and J2s stages of development. Overall, the time taken for collectors to condition in Florida was less than the Sandwich collectors used for P. cygnus in Western Australia.

Vertical distribution and diurnal migration patterns of Jasus edwardsii phyllosomas off the east coast of the North Island, New Zealand - Russell W. Bradford; Barry D. Bruce; Stephen M. Chiswell; John D. Booth; Andrew Jeffs; Simon Wotherspoon (New Zealand Journal of Marine and Freshwater Research, 2005)
The rock lobster Jasus edwardsii forms the basis of important fisheries in south‐eastern Australia and New Zealand. Their long pelagic larval phyllosoma phase (12–24 months) raises many questions as to how the larvae are retained and/or recruited into local populations. Recent attempts to model the dispersal of J. edwardsii phyllosoma have had mixed success at reconstructing settlement patterns. However, these models have either ignored vertical distribution or have used that of the western rock lobster, Panulirus cygnus. We report on the vertical distribution and migration of J. edwardsii phyllosomas, collected in March/April 2003 from the Wairarapa Eddy off the east coast of the North Island, New Zealand, and provide a model to describe their vertical distribution. J. edwardsii phyllosoma were primarily recorded within the upper 100 m over similar depth ranges to those reported for other palinurid and scyllarid species. Well‐defined changes in diel vertical distribution were restricted to late‐stage larvae. Mid‐stage phyllosomas were concentrated in the upper 20 m both day and night. Late‐stage phyllosomas were concentrated in the upper 20 m during the night, but they were absent from the upper 20 m during the day and distributed primarily between 20 and 100 m. Future modelling will benefit from using larval distribution and behaviour patterns specific to J. edwardsii.

Use of digital colour analysis to assess variation within individual adult American lobsters ( Homarus americanus ) and the process of addition of colour in white lobsters - Michael Tlusty (New Zealand Journal of Marine and Freshwater Research, 2005)
A relatively low‐cost method using digital macro‐photography was developed to assess in vivo colour of American lobsters ( Homarus americanus ). Both R*G*B and Commission Internationale de l'Eclairage (CIE) L*a*b systems of colour analysis were used to investigate animal coloration over 11 body locations within each animal. Assuming that lightness (CIE‐L) is biologically important for American lobsters, this species was counter shaded and paired comparisons showed that different colour parameters were all highly correlated among all body locations with the exception of the ventral claw. Using a multiple forward stepwise regression of the five hues on CIE‐L, the hue Green was the most significant parameter accounting for 97% of the variation of CIE‐L. This methodology was then used to assess how dietary white American lobsters add colour to their shell when switched to a diet containing carotenoid. The rate of colour addition was proportional to the amount of carotenoid in the diet, and to the body location. This digital photographic method of colour analysis was useful in that a wide size range of samples could be assessed. All body areas were suitable for colour analysis although relatively flat and smooth locations were most practical.

Marine protected areas in Australia: Towards a coordinated rock lobster industry position - Neil Stump (New Zealand Journal of Marine and Freshwater Research, 2005)
Plans by government to accelerate the establishment of a national representative system of marine protected areas (NRSMPAs) in Australia have caused increasing disquiet within the fishing industry. Rock lobster fishers have raised concerns regarding plans to establish large “multiple‐use” MPAs that may or may not contain a substantial no‐take component in the continental shelf waters adjacent to the coast. Key industry concerns including the potential impacts on present and future harvest rates are examined. The industry response to government MPA policy in each of the major jurisdictions is outlined. An industry position developed at the National Rock Lobster Congress in Perth, Western Australia (September 2003) is put forward. The position advocates the need for an adjustment scheme to account for displaced effort, the need for government commitment to the development of management plans that include the long‐term monitoring of all MPAs, and the need for a thorough risk assessment process to be conducted before the establishment of an MPA. The issues raised in this paper should be relevant to the establishment of MPAs in an international context.

Evolution of operational management procedures for the South African West Coast rock lobster ( Jasus lalandii ) fishery - S. J. Johnston; D. S. Butterworth (New Zealand Journal of Marine and Freshwater Research, 2005)
The commercial fishery for Jasus lalandii, the South Africa West Coast rock lobster, began in the late 1800s and at its peak in the early 1950s yielded an annual catch of 18 000 t. Although this annual catch has dropped to only some 2000 t over recent years, the fishery remains South Africa's third most valuable for landed value. The primary reason for the low total allowable catch (TAC) over these recent years has been a marked drop in somatic growth rate that occurred at the end of the 1980s, for reasons that remain unexplained. A key problem in formulating TAC recommendations with longer‐term objectives in mind, has been uncertainties about likely future trends, particularly in somatic growth and recruitment. To address this problem, an “operational management procedure” (OMP) was adopted in 1997 and has twice been re‐evaluated and modified (in 2000 and 2003) in the light of further data and changing perceptions of resource dynamics. The history of this process is reviewed, concentrating on the most recent modification. In particular, a summary is given of the process by which the merits of alternative management procedures were evaluated over a range of important uncertainties about the dynamics of the resource. This summary includes a discussion of the key trade‐offs between resource rebuilding, future TAC trends and TAC variability, and the eventual choice that was made. The paper concludes by listing a number of lessons learnt concerning best practice for OMP development as this process evolved.

Impact of lunar cycle and swell on the daily catch rate of western rock lobster ( Panulirus cygnus ) using time series modelling - Sukanlaya Srisurichan; Nick Caputi; Jim Cross (New Zealand Journal of Marine and Freshwater Research, 2005)
The western rock lobster fishery is one of the most valuable single‐species fisheries in Australia, valued at AU$300 million per year. The impact of environmental factors such as lunar cycle and swell on the daily catch rate of the western rock lobster ( Panulirus cynus ) is of particular interest in the stock assessment and management of the fishery. The variation in daily catch rates was examined for two periods (migrating period November‐January, non‐migrating period February‐June), at different depths in three management zones for three categories of lobster (undersize, legal size, and setose). Regression and transfer function models for relationships between catch rates and environmental data were considered and compared. The lunar cycle has a significant impact on the daily catch rates with c. 30% lower catch rate during the full moon and c. 20% higher catches near the new moon. This impact occurs mainly during the non‐migrating period both in deep water (40–100 m) and shallow water (

Quantifying the relative intensity of fishing on New Zealand seamounts - Richard L. O'Driscoll; Malcolm R. Clark (New Zealand Journal of Marine and Freshwater Research, 2005)
New Zealand seamounts support major fisheries for several deepwater fish species, including orange roughy ( Hoplostethus atlanticus ) and smooth oreo ( Pseudocyttus maculatus ). Although a high proportion of features in the depth range 500–1000 m have been fished, very little is known about the ecological impacts of bottom trawling on seamounts. The potential impact is likely to be influenced by the spatial extent and frequency of fishing. A new index is presented to assess the relative intensity of trawling on New Zealand seamounts. The fishing effects index (FEI) incorporates information on the density of fishing on the seamount as a proportion of the seabed area and also on tow direction. Detailed fisheries data from more than 250 000 tows were examined to calculate FEI for New Zealand seamounts. The most intensively fished seamounts were on the south Chatham Rise, an area characterised by a large number of relatively small features which were fished serially for orange roughy in the 1980s and 1990s. Other seamounts with high FEI were on the north Chatham Rise, Challenger Plateau, and off the east coast of the North Island. A range of sensitivity analyses indicated that the general rankings of seamounts were relatively robust to the choice of arbitrary thresholds used to assign tows to seamounts.

Reproductive output of male seahorses, Hippocampus abdominalis, from Wellington Harbour, New Zealand: Implications for conservation - Chris M. C. Woods (New Zealand Journal of Marine and Freshwater Research, 2005)
This investigation examines aspects of reproductive output in brooding wild male seahorses, Hippocampus abdominalis, from Wellington Harbour, New Zealand. Previously undocumented, such information is crucial to the management and protection of this species in relation to the CITES Appendix II‐listing of all seahorse species. Brooding males ( n = 46) were captured and kept captive until the release of their juveniles, whereupon the number of juveniles was counted and sampled for standard length (SL) and dry weight (DW). SL (mean ± 1SE) of brooding males was 18.1 ± 0.6 cm and wet weight (WW) 17.6 ± 1.6 g. Number (mean ± 1SE) of juveniles released per brood was 271.2 ± 27. The number of juveniles produced was positively correlated with parent SL, WW, and brood pouch volume. Brood pouch volume was positively correlated with male SL. SL (mean ±1SE) of juveniles released was 16.7 + 0.2 mm and DW 1.2 ± 0.1 mg. Mean SL and DW of juveniles were not correlated with the number of juveniles per brood, parent male SL or parent male pouch volume. The percentage of pouch contents which were non‐viable (i.e., premature or non‐viable eggs) upon juvenile release was low (1.1 ± 0.2%; mean ±1SE of the total pouch contents). Based on findings in this study it is suggested that the CITES 10 cm minimum height restriction, which can be used in lieu of non‐detriment findings to allow sustainable exploitation of seahorses, is not suitable for H. abdominalis from Wellington Harbour as it would appear to only protect small males that produce low numbers of juveniles.

Assessment of size at maturity and gonad index methods for the scallop Pecten novaezelandiae - James R. Williams; Russell C. Babcock (New Zealand Journal of Marine and Freshwater Research, 2005)
Size at sexual maturity and gonad indices appropriate for measuring reproduction were examined in the scallop Pecten novaezelandiae at two sites in the Hauraki Gulf, New Zealand. Size at maturity was assessed using gonad visual grading and allometric calculation methods. Size of the smallest mature individual varied from 52 to 59 mm shell height between sites. In general, 50% of scallops were mature at 60 mm and 100% were mature at 65 mm. Small differences in size at maturity between sites may be related to differences in environmental conditions that affect growth rates. Our results were broadly similar to those reported from the South Island, however direct comparisons were compromised by the wide range of methods and definitions used in previous studies. Here we applied a method that directly scaled gonad mass to shell height, removing the need for a reference mass, and combined it with an objective method to establish size at maturity that will facilitate future comparisons.

Description of Panulirus brunneiflagellum new species with notes on its biology, evolution, and fisheries - Hideo Sekiguchi; Ray W. George (New Zealand Journal of Marine and Freshwater Research, 2005)
The new species is distinguished from its nearest relatives by the colour and patterning of the anntennual rami. Panulirus brunneiflagellum is morphologically close to P. japonicus and is restricted to the subtropical Ogasawara Islands in the west Pacific. It probably became isolated from the P. japonicus stock with the development of the unique Ogasawara oceanic circulatory system as a result of the deflection of the Kuroshio subgyre as the Iwo‐Jima Ridge uplifted. Over 90% of the annual production of c. 5 t is frozen and transported to the Tokyo market, Japan.

Long‐term trends in the recreational lobster fishery of Florida, United States: Landings, effort, and implications for management - William C. Sharp; Rodney D. Bertelsen; Vernon R. Leeworthy (New Zealand Journal of Marine and Freshwater Research, 2005)
In Florida, United States, the Caribbean spiny lobster, Panulirus argus, supports an important commercial fishery and also perhaps the most intensive recreational fishery of any lobster species, with sales of recreational lobster fishing permits exceeding 100 000 annually. For the past decade, we have used mail surveys of recreational lobster license holders to estimate spatially explicit landings and fishing effort when recreational fishers are most active—during the state's “Special Two‐Day Sport Season”, which takes place just before the opening of the commercial season, and during the first month of the regular recreational season, which coincides with the commercial season. From 1993 through 2002, fishing effort during the Special Two‐Day Sport Season has ranged from 60 000 to 112 000 person‐days, and landings have ranged from c. 112 to 255t. Both fishing effort and landings have varied without trend. Fishing effort during the regular season over the same period has ranged from 261 000 to 514 000 person‐days, and landings have ranged from 434 to 825 t. Fishing effort has shown a marginally statistically significant decreasing trend, the result of a progressive decrease in effort since 1999. The largest proportion of both fishing effort and landings was concentrated along the south‐east coast. Despite the recent decrease in landings, the proportion of total landings made by the recreational fishery has increased. From 1993 through 1998, the fishery was responsible for c. 30% of commercial landings; by 2001, that percentage increased to nearly 40%. Such a shift in landings away from the commercial trap fishery toward the recreational fishery was recognised as a potential but unintended effect of the ongoing management plan of restricting effort in the commercial trap fishery. Our 2001 surveys revealed that recreational lobster fishers spent more on a person‐day basis than the general visitor to the Florida Keys did, but less than those visitors using the region's coral reefs. Consequently, managers must establish management strategies that allow the coexistence of this resource's user groups and also incorporate the social and environmental concerns of nonuser groups.

Growth, diet, movement, and abundance of adult banded kokopu ( Galaxias fasciatus ) in five Coromandel, New Zealand streams - David W. West; Ian G. Jowett; Jody Richardson (New Zealand Journal of Marine and Freshwater Research, 2005)
Banded kokopu populations were surveyed seasonally over 1 year in five Coromandel streams to determine the influence of food supply on diet, growth, abundance, and movement. Streams with high benthic invertebrate abundance and drift of aquatic origin had high fish abundance. However, terrestrial drift was the dominant food for adult banded kokopu over all seasons and streams, on average comprising 75% of their diet by number and 89% by weight. Annual growth rates of tagged individuals ranged from 3 mm to 16.5 mm, with smaller fish growing faster than large fish. Low growth rates of large fish were consistent with the recapture of a fish that had only grown from 195 mm to 215 mm in 7 years. Our observations confirmed the strong association between banded kokopu, pool habitat, and cover, and also indicated that high fish abundance restricted growth rates and movement and increased interaction.

How do spiny lobster post‐larvae find the coast? - Andrew G. Jeffs; John C. Montgomery; Chris T. Tindle (New Zealand Journal of Marine and Freshwater Research, 2005)
The larvae or phyllosomes of many species of spiny lobsters (Palinuridae) are known to complete their development in offshore oceanic waters. Phyllosomes metamorphose to non‐feeding, nektonic post‐larvae or pueruli, which move into shallow coastal waters where they settle to become benthic dwelling juveniles. There is growing evidence that the movement of pueruli is directed toward the coast rather than a process of random dispersal. The migration inshore by the non‐feeding pueruli is likely to be one of the more extreme examples of onshore orientation among marine organisms, but is still poorly understood. This article provides a synthesis of the current state of knowledge of the possible cues and sensory mechanisms that might be used by pueruli of spiny lobsters for orienting toward the coast from offshore waters. The review is used to identify the potential cues that would benefit from future research efforts.

First records of Scorpaena onaria (Scorpaeniformes: Scorpaenidae) from the southwestern Pacific Ocean, and comparisons with the Northern Hemisphere population - Hiroyuki Motomura; Chris D. Paulin; Andrew L. Stewart (New Zealand Journal of Marine and Freshwater Research, 2005)
Scorpaena onaria Jordan & Snyder (Scorpaeniformes: Scorpaenidae), previously known only from the northwestern Pacific Ocean, is reported from the southwestern Pacific Ocean for the first time on the basis of 19 specimens. The southwestern Pacific specimens are regarded as a southern population of S. onaria, characterised by a shorter supraocular tentacle and larger body size compared with the northwestern Pacific specimens. The southern population is described in detail including comparisons with all known Indo‐Pacific species of the genus Scorpaena. Analyses of 37 measurements of the southern population of S. onaria found that relative orbit diameter and second anal‐fin spine length became significantly smaller with growth. Initially cycloid, the scales enclosed by the posterior tips of the upper and lower opercular spines and opercular margin change to ctenoid with growth at c. 160–170 mm standard length. A mature female differed from an immature female and males in having a longer upper jaw, steeper dorsal profile of the snout, and shorter nasal spine. As a consequence, the species previously reported as S. neglecta from the Andaman Sea and northwestern Australia was re‐identified as S. onaria.

Migratory behaviour of spawning rainbow trout ( Oncorhynchus mykiss ) in the Tongariro River, New Zealand, after habitat alteration - Mark R. Venman; Michel Dedual (New Zealand Journal of Marine and Freshwater Research, 2005)
The movements of 92 adult rainbow trout ( Oncorhynchus mykiss ) from Lake Taupo into the Tongariro River, New Zealand, were monitored using radio‐telemetry every 3 days during the main spawning period between May and November 2003. This study repeated one previously conducted in 1995. Differences in spawning site preference and resting locations between 1995 and 2003 probably reflect differences in the nature of the river as a result of major natural floods that occurred in 1998. Average migration times were slower than in 1995 and the correlation between flow and mean daily movement was less distinct owing to the dry and settled weather during July and August, although fish did respond to freshets when they occurred. Peak movement occurred between 1600 and 2000 h NZ Standard Time with no movement occurring between midnight and 0400. Fish adjusted their movement in response to changing photoperiod. Nineteen fish were observed above the mouths of natal tributary streams for several weeks in the main river stem before entering these tributaries.

Prey selection and dietary overlap of shortfinned ( Anguilla australis ) and longfinned (A. dieffenbachii ) eels during summer in the Horokiwi Stream, New Zealand - P.M. Sagar; E. Graynoth; G. J. Glova (New Zealand Journal of Marine and Freshwater Research, 2005)
Benthic macroinvertebrates were collected and the diets of shortfinned eels ( Anguilla australis ) and longfinned eels ( Anguilla dieffenbachii ) inhabiting a small coastal New Zealand stream were examined to investigate intraspecific and interspecific trophic partitioning and prey selection. Our results showed intraspecific segregation of preferred prey among three size classes of juvenile shortfinned eels, but there was significant overlap between different size classes of longfinned eels. All size classes of both species of eel fed nocturnally on similar prey, and so there was no indication of temporal or trophic segregation. Therefore, habitat separation is assumed to be the main mechanism to reduce interspecific competition in these two co‐occurring species of eels.

Allozyme variation in European lobster ( Homarus gammarus ) throughout its distribution range - Knut E. Jørstad; Eva Farestveit; Eamonn Kelly; Costas Triantaphyllidis (New Zealand Journal of Marine and Freshwater Research, 2005)
The European lobster, Homarus gammarus, is a high value species, which is widely distributed from the northern part of Norway to Morocco in North Africa. It is also found throughout the Mediterranean including the Aegean Sea. Knowledge of the genetic structure is necessary for rational management of exploited species. As part of a comprehensive genetic investigation of European lobster (EU‐project “Genetics of European Lobster”), 1514 lobsters from 14 locations were analysed for six polymorphic allozyme loci. Despite generally low levels of genetic differentiation (overall F ST = 0.016), the tests for population differentiation revealed highly significant values for all loci investigated. In particular, the lobsters from three areas including northern Norway, the Netherlands, and Aegean Sea in the Mediterranean were genetically different from lobsters from other regions. Lobsters from northern Norway have 30% of the genetic diversity observed in the samples from other areas, and polymorphism was only detected at the IDHP‐1* locus. A new slow‐moving allele at the GPI‐1* locus was found in the samples from the Aegean Sea. Pairwise F ST comparisons, as well as a UPGMA dendrogram based on Nei's genetic distance (calculated from allele frequencies across the six loci investigated), confirm the separate main groupings.

Modelling the effects of Marine Protected Areas (MPAs) on the southern rock lobster ( Jasus edwardsii ) fishery of Victoria, Australia - David Hobday; André E. Punt; David C. Smith (New Zealand Journal of Marine and Freshwater Research, 2005)
Since 2002, 5.3% of the Victorian coastal waters have been declared as Marine Protected Areas (MPAs). These are aimed at safeguarding important marine habitats and species, significant natural features, and areas of cultural heritage and aesthetic value. However, MPAs impact the fishery for southern rock lobster ( Jasus edwardsii ) , as total allowable catches (TACs) were previously set to allow the biomass to recover to pre‐specified target levels. The model on which assessments and risk analyses are based is extended to include the impact of MPAs. The MPAs and the area open to fishing are modelled as subpopulations with different levels of mortality and consequently different density and population size‐structure. A range for the probability of a lobster moving from a MPA to the fished area from 0 to 15% is considered, based on the results of tagging studies. The reduction of biomass available to the commercial fishery because of the introduction of MPAs is estimated to be 8% and 16% (Western and Eastern Zones) respectively. The results of a risk assessment show that if the current TACs are maintained, the time to increase the biomass available to the commercial fishery by 50% would be delayed 5–9 years in the Western Zone and 1–4 years in the Eastern Zone because of the impact of displaced effort. In contrast, spawning biomass in the Eastern Zone is currently below the agreed limit reference point, and the introduction of MPAs would enhance the rate of recovery, although only marginally initially, faster than the absence of the MPAs.

Comparative morphology and evolution of the reproductive structures in spiny lobsters, Panulirus - R. W. George (New Zealand Journal of Marine and Freshwater Research, 2005)
Males and females of the spiny lobster genus Panulirus have evolved a range of modifications to the penile process and the thoracic sternum respectively. The pattern of evolution of the reproductive structures confirms the previously presented patterns of speciation in Panulirus, based on genetics and on the morphology of adults, larvae, and pueruli. These structures may have themselves helped to initiate speciation in Panulirus and may have evolved as a consequence of the longer lasting spermatophoric mass and the delayed use of sperm by the females of some species. During courting, body caresses enable males to assess the size of females. The evolution of different copulatory structures heightens the probability of same‐species mating and for the male to confirm a female's size and reproductive status, and ejaculate and correctly position an external spermatophore of the required size.

Conservation of unique patterns of body markings at ecdysis enables identification of individual spiny lobster, Jasus edwardsii - Alison B. MacDiarmid; Megan D. Oliver; Robert A. Stewart; Dharini Gopal (New Zealand Journal of Marine and Freshwater Research, 2005)
Southern temperate rock lobsters ( Jasus edwardsii ) develop complex body markings and spines that vary uniquely among individuals. These markings are retained after moulting allowing individuals to be recognised without capture or handling in the field. This enables the impact of capture, handling, and tagging procedures on subsequent movements to be more confidently evaluated. Recognition of individuals by natural markings allows post‐moult lobsters that were externally tagged and held in large communal tanks to be correctly retagged. Distinctive markings on the pedate processes and on the epistoma, as well as the number and placement of small spines on the antennular plate are particularly useful for recognising individuals. It is highly likely that the other Jasus species and the brightly patterned and coloured Panulirus species have similar body markings and spine patterns that would aid recognition of individuals.

Observations on Gastrotricha from a sandy beach in southeastern Australia, with a description of Halichaetonotus australis sp. nov. (Gastrotricha, Chaetonotida) - Warwick Nicholas; M. Antonio Todaro (New Zealand Journal of Marine and Freshwater Research, 2005)
Several species of Gastrotricha were found among samples of nematodes extracted from a sandy ocean beach, South Broulee beach, in southeastern Australia. One of these Gastrotricha turned out to be a species new to science which is described as Halichaetonotus australis sp. nov. in this study. Although the spines of the hydrofoil scales resemble those of the cosmopolitan H. aculifer, a distinctive feature of the new species is the presence of three prominent posterior dorsal spines. These are exaggerations of the keels found on the dorsal overlapping scales that cover the dorsal surfaces of the head, neck, and trunk. The spines are almost as long as the rami of the terminal furca. H. australis sp. nov. also resembles H. marivagus, but differs in lacking both a cephalion and hypostomion. Freeze drying is introduced as a preparation method for scanning electron microscopy of Gastrotricha.

Characterisation of the recreational fishery for southern rock lobster, Jasus edwardsii, in Tasmania, Australia: Implications for management - Jeremy M. Lyle; Alastair J. Morton; Jane Forward (New Zealand Journal of Marine and Freshwater Research, 2005)
Southern rock lobster ( Jasus edwardsii ) support significant commercial and recreational fisheries in Tasmania, Australia. Since the mid 1990s the number of persons holding recreational lobster licences increased by over 80%, with c. 15 500 persons licensed in 2002/03. Assessment of the recreational fishery has been undertaken periodically since 1996 using a telephone‐diary survey method. The fishery was concentrated off the south‐east and east coasts of Tasmania and characterised by strong seasonality in catch and effort, which peaked markedly early in the fishing year (November‐January). Although pots were the most popular fishing method, daily catch rates by divers were more than double those for pots. Divers selectively harvested larger lobsters than those taken by pots and more frequently attained the daily bag limit of 5 lobsters. The estimated recreational harvest increased significantly since 1996/97 and in 2002/03 effectively reached a management trigger level of 10% of the total allowable commercial catch, flagging a review of recreational management arrangements.

Review - John D. Booth; W. Richard Webber; Hideo Sekiguchi; Emmanuel Coutures (New Zealand Journal of Marine and Freshwater Research, 2005)
Scyllarid lobsters, together with the palinurids, have a long‐lived, planktonic phyllosoma larval phase in their early life history followed by a much briefer postlarval phase which at settlement completes the planktonic period of their life cycle. Information on scyllarid larval biology and recruitment mechanisms is fragmentary. Scyllarid species exhibit a wide range of larval recruitment strategies and durations, from entire larval and postlarval phases being completed in just a few weeks within lagoons, through to species that become widely dispersed in ocean basins over many months. In contrast, the phyllosomas of all palinurids so far investigated invariably, over many months, become widely dispersed in the open ocean well beyond the continental shelf. Among scyllarid species a general relationship is apparent between adult size and the extent of larval dispersal. During the planktonic period currents, in combination with larval vertical migratory behaviour, probably play an important role in larval dispersal and return. Although varying greatly in size, the postlarval nisto of most scyllarids appears to be similar in behaviour to the puerulus of palinurids. Nistos are usually (if not always) non‐feeding and appear to alternate between swimming at night and resting on the bottom during the day as they move inshore to regain adult grounds before settling and metamorphosing to the first juvenile lobster instar. Those scyllarids with a somewhat abbreviated larval duration and mainly coastal larval distribution—the “flat” species of Ibacus and Thenus —appear to have succeeded in exploiting local currents and biotic systems to restrict larval dispersal and maintain their place. Based on the characteristics of the larvae and their recruitment mechanisms, there is support for the present division of the Scyllaridae into its four subfamilies, but also backing for revision, particularly of the Ibacinae.

Freshwaters of New Zealand. Edited by JonHarding, PaulMosley, CharlesPearson and BrianSorrell. Published in 2004 by New Zealand Hydrological Society (P.O. Box 12–300, Wellington) and New Zealand Limnological Society. 746p., hardcover. ISBN: 0–476–00708–9. Price: NZ$69.95 (orders: admin@hydrologynz.org.nz). - Kit Rutherford (New Zealand Journal of Marine and Freshwater Research, 2005)

Water quality and thermal regime of the Motueka River: Influences of land cover, geology and position in the catchment - Roger G. Young; Aaron J. Quarterman; Rebekah F. Eyles; Robert A. Smith; William B. Bowden (New Zealand Journal of Marine and Freshwater Research, 2005)
We examined the effects of land use, geology, and longitudinal position within the river network on water quality and thermal regime at 23 sites within the Motueka River catchment. The concentrations of suspended solids, nitrate nitrogen, total nitrogen, Escherichia coli, and Campylobacter were higher at sites draining pastoral and horticultural land than in similar‐sized native or plantation forest streams. Average daily mean temperature and minimum temperature in summer and maximum winter temperature were higher in unshaded pastoral and horticultural streams than at native forest sites. Differences in water quality and thermal regime were also observed among sites with contrasting geology. Conductivity, pH, and minimum winter temperatures were highest at sites draining marble terrain. In contrast, longitudinal patterns in water quality and temperature regime along the 120‐km length of the river were relatively weak, although longitudinal patterns in amplitude of daily temperature fluctuation matched theoretical predictions. In this study, differences in land use appeared to have the strongest influence on most water quality and thermal variables examined. However, geology was an important factor explaining variation in certain variables (e.g., pH and conductivity). Longitudinal patterns in water quality and temperature were relatively weak and in many instances were linked with longitudinal patterns in land use and geology rather than catchment location alone.

Immature Diptera (excluding Culicidae) inhabiting phytotelmata in the Auckland and Wellington regions - José G. B. Derraik; Allen C. G. Heath (New Zealand Journal of Marine and Freshwater Research, 2005)
This study records the Diptera fauna (excluding Culicidae) breeding in phytotelmata in the Auckland and Wellington regions of New Zealand, particularly in native forest habitats. Diptera larvae were relatively abundant in the leaf axils of the native epiphyte Collospermum hastatum, and in the fallen leaves of the native nikau palm Rhypalostylis sapida. Chironomidae and Tipulidae were the most common families collected, but larvae of Anisopodidae, Ceratopogonidae, Empididae, Psychodidae, and Syrphidae were also present.

Field calibration of a formula for entrance mixing of river inflows to lakes: Lake Taupo, North Island, New Zealand - Robert H. Spigel; Clive Howard‐Williams; Max Gibbs; Scott Stephens; Barry Waugh (New Zealand Journal of Marine and Freshwater Research, 2005)
Field measurements were used to validate predictions for the initial dilution of negatively buoyant, cold‐water inflows to Lake Taupo, as part of a study to quantify mixing processes associated with the two largest inflows to the lake. The predictions were made using a formulation originally derived for positively buoyant, warm‐water inflows to cooling ponds. The formulation predicts the total dilution of an inflow during its inertia‐dominated phase between its entrance to the lake and the point where buoyancy forces are great enough to cause the inflow to plunge and form a submerged density current. In one of the measured inflows, the inflowing jet was free to entrain from both sides; in the other, entrainment was restricted on one side by attachment of the inflowing jet to the shoreline of a bay just upstream of the plunge point. In the former example, the unmodified coefficients from the cooling pond formulation provided an excellent prediction of initial dilution. In the latter example, entrainment was reduced and different coefficients were derived. In both examples the inflows remained attached to the lake bed throughout their course until their liftoff at depths of 45–55 m to form interflows. The difference between coefficients for the two inflows indicates that the coefficient values should be considered site‐specific. The formulation is not valid for inflows that separate from the bottom of the inflow channel before plunging. The entrance mixing formulation was incorporated in a more general model of lake stratification, DYRESM, which already includes a well‐documented routine for routing underflows down submerged channels on the bed of a lake. Application of the model to the inflows measured in Lake Taupo gave good results for two model outputs that were not involved in the calibration of the entrance mixing formulation, but that are affected by the result of the initial dilution calculation—the temperatures in the river plume after it has plunged, and the insertion depth.

Trap‐based indicators of egg production following increases in minimum legal size in Homarus americanus fisheries - M. John Tremblay; Marc Lanteigne (New Zealand Journal of Marine and Freshwater Research, 2005)
Minimum legal size (MLS) is an important conservation measure in trap fisheries for Homarus americanus. MLS has increased in several management areas in the Canadian Maritimes since 1987. A key conservation objective has been to increase egg production, with predictions of the effects of MLS increase based on egg‐per‐recruit models. We evaluated whether expectations of increases in ovigerous females (OF) were realised when MLS was increased. Data were examined from at‐sea samples of the commercial trap catch from 11 ports from 1986 to 2003. OF indicators were developed based on the OF catch‐per‐unit‐effort (CPUE) of different sizes, and on the percentage (PCT) of females that were ovigerous. Because there were within‐season increases in CPUE and PCT, annual indicators were based on regressions of CPUE on day in the season. There was considerable variability in all the time series of OF annual indicators and any effects of smaller MLS increases could not be detected. Increases in OF indicators were evident in areas that undertook the largest MLS increases (6–6.5 mm CL).

Impact of minimum legal size increases on egg‐per‐recruit production, size structure, and ovigerous females in the American lobster ( Homarus americanus ) population off the Magdalen Islands (Quebec, Canada): A case study - Louise Gendron (New Zealand Journal of Marine and Freshwater Research, 2005)
In the mid 1990s, American lobster ( Homarus americanus ) from Canadian waters was considered overfished based on estimated levels of egg‐per‐recruit production (EPR). In 1997, the Department of Fisheries Oceans responded by adopting a goal of doubling the level of EPR from its 1996 level. In the Magdalen Islands (Quebec), results from a simulation model indicated that doubling EPR could be reached by increasing the minimum legal size (MLS) from 76 mm to 83 mm carapace length. This was done at a pace of 1 mm per year from 1997 to 2003. Following the increase of MLS, the size structure, mean size, and the abundance of ovigerous females improved significantly in the catches. However, levels of fishing effort are still very high. This could cause undesirable effects such as altering sex ratios and size structure of males, which could lead to sperm limitation, and reducing the contribution of multiple spawners to egg production, which could become an issue if egg quality is important. Consideration of these issues leads to the recommendation of a multidimensional approach to lobster conservation.

Behaviour of hatchery‐reared and wild‐caught 4th and 5th stage American lobsters, Homarus americanus - Kathleen M. Castro; J. Stanley Cobb (New Zealand Journal of Marine and Freshwater Research, 2005)
Behavioural deficiencies in 4th and 5th stage hatchery‐reared lobsters were examined using time budget analysis and predator trials. Hatchery‐reared 4th stage lobsters were found to behave differently than wild‐caught lobsters and differences existed between hatchery‐reared lobsters from different sources. Local hatchery‐reared 4th stage lobsters spent less time on shelter and suffered higher predator rates in laboratory trials than both wild‐caught 4th stage and lobsters reared in a hatchery in Maine. Fifth stage hatchery‐reared lobsters spent significantly more time in shelter than their wild‐caught counterparts. These differences may be attributable to the lack of development of proper predator‐avoidance behaviour and need to be understood and corrected to maximise the effect of enhancement projects.

Can additional abundance indices improve harvest control rules for New Zealand rock lobster ( Jasus edwardsii ) fisheries? - Nokome Bentley; Paul A. Breen; Susan W. Kim; Paul J. Starr (New Zealand Journal of Marine and Freshwater Research, 2005)
Although New Zealand rock lobster ( Jasus edwardsii ) fisheries can be assessed with a sophisticated Bayesian length‐based model, these assessments are expensive and time consuming; they cannot be conducted for each area every year. Harvest control rules are increasingly important management tools in New Zealand rock lobster fisheries. Recent work has developed and evaluated procedures for rebuilding or maintaining lobster stocks based on criteria agreed by stakeholders. Most management procedures depend on a single abundance index, often catch per unit of effort (CPUE). When management procedures react slowly to changes in vulnerable biomass, allowable catches get out of phase with the stock, causing large oscillations in both catches and CPUE. Lags between data and management actions and “latent years” are features of rules that reduce responsiveness. This study explores ways to improve the responsiveness of harvest control rules by using additional data to predict changes in vulnerable biomass. Four data sets are examined: CPUE trends, pre‐recruit indices, puerulus settlement indices, and size frequencies. Only pre‐recruit indices, which were explored with a simple delay‐difference model based on parameter estimates from recent assessments, appeared to have immediate potential for use in improving management procedures.

Developing and evaluating a size‐structured stock assessment model for the American lobster, Homarus americanus, fishery - Yong Chen; Minoru Kanaiwa; Carl Wilson (New Zealand Journal of Marine and Freshwater Research, 2005)
The American lobster, Homarus americanus, is the most important fishery in the north‐east United States. Over the last 20 years, the Collie‐Sissenwine (catch‐survey) model has been used in estimating fishing mortality in the fishery. This is then compared with a biological reference point derived from an egg‐per‐recruitment model for determining the status of the stock. However, the complexity of the fishery and population biology for American lobster, data limitations, and uncertainty about underlying parameters call for the development of stock assessment models with more biological detail. Complex and simple modelling approaches are complementary and both are likely to remain useful for such an important and complex fishery. The objective of this study is to develop a size‐structured stock assessment model for the American lobster. The proposed stock assessment model includes a set of size‐structured, seasonal, and sex‐specific population dynamics models and a statistical approach incorporating data of different sources. Using a fishery simulation based on the information on the lobster fishery in the Gulf of Maine, we evaluated the performance of the proposed model in the presence of biased errors in various model variables. This study suggests that the proposed stock assessment model performs well in retrieving the population dynamics of the simulated lobster and is rather robust to the biased errors in growth, fishing selectivity, and landings. Future studies need to focus on the evaluation of the model performance under different scenarios with both biased and random errors.

Status of the major lobster fisheries in India - E.V. Radhakrishnan; V.D. Deshmukh; Mary K. Manisseri; M. Rajamani; Joe K. Kizhakudan; R. Thangaraja (New Zealand Journal of Marine and Freshwater Research, 2005)
Commercial exploitation of lobsters from the Indian seas began in the 1950s. Annual landings have been declining from a peak of 4075 t in 1985 to 1364 t in 2002. Major fisheries were located on the north‐west, south‐west, and south‐east coasts. Among the 12 species recorded, only four species of spiny lobsters (three littoral and one deep sea) and one species of slipper lobster are commercially important. At Kayalpattinam and Tharuvaikulam, on the south‐east coast, lobster landings sharply declined for the gill‐net fishery. Of the two species that contributed to the fishery, Panulirus ornatus and Panulirus homarus, the latter has been more affected owing to high vulnerability to fishing activities. Catch composition analysis of the trammel‐net fishery showed that 35% of the landings consisted of P. homarus in the size range of 23–50 mm carapace length. On the north‐west coast, the spiny lobster Panulirus polyphagus and the slipper lobster Thenus orientalis are incidentally caught in trawl nets. However, the fishery for T. orientalis in the waters off Mumbai lasted only up to 1994. Large‐scale exploitation of spawning females, which formed 60% of the total catch, might have been detrimental to the recruitment process resulting in rapid decline and total collapse of the fishery. Abundance of P. polyphagus reached its maximum during September, constituting 23% of the average annual landing during 1988–2002. A high exploitation ratio (>0.7) indicated over‐fishing of the stock. Repeated spawning and high annual egg production are probably responsible for sustaining the stock, despite over‐exploitation. Major problems confronting the resource management of the multi‐gear and multi‐species lobster fisheries in India are discussed. An operational project, involving fisher community, has been taken up for creating awareness of the need for sustainable exploitation of the resource. Regulatory measures, such as closure of the fishery during the peak of the breeding season, ban on trammel‐net, mandatory release of egg‐bearing lobsters, and establishment of lobster sanctuaries are suggested to the State Governments for implementation.

Growth and moulting of captive Panulirus homarus homarus in Kenya, western Indian Ocean - A. J. Kulmiye; K. M. Mavuti (New Zealand Journal of Marine and Freshwater Research, 2005)
Panulirus homarus homarus is the most widely distributed of the three P. homarus subspecies and is the second most important spiny lobster in the Kenyan lobster fishery after Panulirus ornatus. Growth and moulting of lobsters held in concrete tanks with a flow‐through sea‐water system and at ambient temperatures, were monitored for 18 months (October 2001 ‐ March 2003). Both moult increment and moulting frequency were inversely correlated with size. Mean moult increment ranged from 4 mm in the 36–45 mm carapace length (CL) size class to 0.6 mm in the 86–95 mm CL size class. Mean intermoult period increased from 49 days in the 46–55 mm CL size class to 66 days in the 76–85 mm CL size class. Growth rates were 19% and 46% higher for males and females, respectively during the south‐east monsoon (low temperature) season than during the north‐east monsoon (high temperature) season. A shift in energy use from growth to reproduction rather than the influence of temperature was responsible for the variation in the growth rates between the two seasons. Marking‐induced injury caused a significant 65% growth reduction in the affected individuals. Mean moult increments calculated for most size classes of uninjured lobsters were comparable to those observed in the subtropical P. homarus rubellus reared in the laboratory in South Africa but smaller than those reported in the Indian P. homarus under similar conditions.

Longevity, growth, reproduction and a description of the fishery for silver sweep Scorpis lineolatus off New South Wales, Australia - John Stewart; Julian M. Hughes (New Zealand Journal of Marine and Freshwater Research, 2005)
Size at age, growth rates, seasonality of spawning, and size at maturity were described for the silver sweep Scorpis lineolatus off the coast of New South Wales, Australia. Estimates of age were made by counting annual zones in sections of otoliths. The ageing technique was validated using young‐of‐the‐year fish, staining fish with tetracy‐cline, and by marginal increment analysis. Silver sweep exhibited extreme longevity with an observed maximum age of 54 years and more than 50% of the fishery being greater than 15 years old. Growth was rapid during the first few years before reaching sexual maturity at 2–3 years and at a length of c. 17 cm fork length, after which growth slowed dramatically. Silver sweep displayed a winter spawning period. The fishery is unusual in that despite heavy fishing pressure and rapidly declining catches the age structure of the catch suggests a population that has been subjected to minimal fishing mortality. It is proposed that the large declines in commercial landings may be the result of serial depletion on local reefs and that current landings are being taken from schools of fish that have received little fishing pressure historically.

Feeding ecology of juvenile spiny lobster, Panulirus interruptus, on the Pacific coast of Baja California Sur, Mexico - Verónica Castañeda‐Fernández‐de‐Lara; Elisa Serviere‐Zaragoza; Sergio Hernández‐Vázquez; Mark J. Butler (New Zealand Journal of Marine and Freshwater Research, 2005)
Many aspects of the early life history of the red lobster Panulirus interruptus are little known, including the relationship between habitat structure, food resource availability, and nutrition of juveniles. We investigated the spatial and temporal differences in food intake, diet composition, and nutritional condition of juveniles at two sites along the Pacific coast of the Baja California Peninsula (Mexico) with contrasting oceanographic and biological conditions. One site (Arvin) is located inside a protected bay, Bahía Tortugas, where the waters are cooler and temperate seagrasses and macroalgae are the dominant benthic flora. The second site (Queen) in Bahía Sebastían Vizcaíno was located along a more open coastline where seawater temperatures were higher and the benthic flora more indicative of warmer seas. At both sites, we randomly sampled epifauna within vegetated habitats to estimate the seasonal availability of food resources for juvenile lobsters from autumn 2001 until summer 2002. Concurrently, we used traps to sample P. interruptus juveniles for stomach content analysis. At both sites, Amphipoda, Gastropoda, and Polychaeta dominated the epifauna assemblages, as determined by an Index of Importance. Juvenile P. interruptus primarily consumed crustaceans (mostly amphipods and isopods) and vegetal material (surf‐grass Phyllospadix spp. and calcareous algae), but their food spectrum was wide. Manly's Index of Resource Selection indicated that lobsters preferred some prey (e.g., Brachyurans) over others despite their low Index of Importance. Despite marked differences in the types of food and their availability between sites, there were no significant differences in the nutritional condition (e.g., relative weight of the digestive gland) of lobsters at the two sites. However, the nutritional condition of lobsters was effected during some seasons. In particular, their condition deteriorated during the spring (April 2002) at Arvin, as did the proportion of individuals with empty stomachs. This study shows the feeding adaptation capacity of the juvenile California spiny lobster P. interruptus to different environmental conditions prevalent in Centre Baja California Peninsula.

Organic matter production of American lobsters ( Homarus americanus ) during impoundment in Maine, United States - Michael F. Tlusty; Karolina Preisner (New Zealand Journal of Marine and Freshwater Research, 2005)
Lobster impoundments are dammed coastal embayments utilised to hold American lobsters ( Homarus americanus ) before shipping to market. The impacts of lobster impoundments on the environment have not been previously studied. Here, the digestive functioning of American lobsters was examined to assess the quantity and quality (TVS, total volatile solids) of lobster faeces produced under the temperatures and feeding regimens these animals were subjected to during the impoundment period. Overall it was determined that quantity and quality of faeces did not differ among the experimental temperatures (5, 10, and 15°C), and that animals fed every 1–2 days produced greater quantity and quality of faeces than those fed every 3–18 days, or those animals fed less than every 18 days. As a first estimate of organic matter production in active lobster impoundments, it was calculated that a typical lobster impoundment produced 0.79 ± 0.35 (average ± 1 SD) g TVS m ‐2 day ‐1 during the impoundment period, equivalent to 3.11 ± 0.60% of the total weight of lobsters stocked into the impoundment. This level of organic matter production is below the level produced by other aquaculture operations, and that at which benthic impacts might be expected.

Foreword - Stewart D. Frusher; Caleb Gardner (New Zealand Journal of Marine and Freshwater Research, 2005)

Characterising shelter preferences in captive juvenile Jasus edwardsii (Palinuridae) - John D. Booth; Dieter Ayers (New Zealand Journal of Marine and Freshwater Research, 2005)
Any attempt to enhance rock lobster production by increasing survival after settlement, or by ongrowing or outplanting young juveniles, requires knowledge of the shelter preferences of young juveniles. For juvenile Jasus edwardsii in the wild these are not well known. Information available suggests that juveniles up to c. 35 mm carapace length (CL) occupy shelters that generally conform closely to their body dimensions but that larger juveniles use shelters of more variable dimension, often much larger than their body size. We investigated mainly physical factors important in shelter choice by 15–59 mm CL (c. 2–24‐month‐old juveniles) in laboratory tank experiments. In overnight tests, all sizes of juvenile lobster chose to occupy holes (shelters with sides) over open horizontal gaps. Preference for open horizontal gaps versus horizontal crevices (where the height reduces from a maximum at the mouth to zero at the opposite end) was much less clear‐cut; choice varied according to lobster size. For the number of entrances into holes, there was evidence for an ontogenetic shift in preference, small lobsters preferring two openings over one, whereas those >30 mm CL (c. 9 months old) preferred one over two. For lobsters J. edwardsii in that there was a close and proportional relationship between lobster size and shelter size; what differed was that the open gaps chosen in the tanks by the smallest lobsters (15–19 mm CL) were larger than the holes used in the tank experiments and 30–50% larger than those reportedly used in the field. For lobsters >40 mm CL, the holes and gaps chosen in the tanks were generally larger and more variable in size, as in the field.

Growth, repetitive breeding, and aquaculture potential of the spiny lobster, Panulirus ornatus - T. Senthil Murugan; M. C. Remany; T. Mary Leema; JHA Dilip Kumar; J. Santhanakumar; M. Vijayakumaran; R. Venkatesan; M. Ravindran (New Zealand Journal of Marine and Freshwater Research, 2005)
A pair of subadult Panulirus ornatus was reared in the laboratory from July 2001. The female grew from 0.6 to 1.3 kg and the male from 0.5 to 1.6 kg in 2 years before the first mating in July 2003. In 6 months, from July to December 2003, the pair mated and spawned 3 times, producing 1.6 million eggs and 1.1 million phyllosoma larvae. Mating occurred 25 and 63 days after moulting. The female spawned 2–3 days after mating and the incubation time ranged from 23 to 27 days. The phyllosoma larvae were released over 2 successive days. The growth rate reduced after first mating in both the male and female and the female expended 42% of the total weight gain for egg production.

Effects of diet on the growth, survival, and condition of sea‐caged adult southern rock lobster, Jasus edwardsii - Simon R. Bryars; Michael C. Geddes (New Zealand Journal of Marine and Freshwater Research, 2005)
Live‐holding of fisheries‐caught adult southern rock lobster (Jasus edwardsii) presents a means of value‐adding to the South Australian commercial catch through strategic marketing and product enhancement. This study investigated the effects of live mussel and three manufactured diets on the survival, growth, and condition of sea‐caged adult J. edwardsii held for an extended period of 29–30 weeks during the closed fishing season. Two trials were conducted in existing industry cage systems. All four diets tested were successful in keeping lobsters alive, promoting growth at moult, and maintaining/improving the condition of lobsters. Unfed lobsters had lowered survival, negative or zero growth at moult, and lowered condition. All lobsters moulted during the trials. Addition of 1% mussel mince to pellets as a feeding stimulant did not increase survival or growth. Males showed substantially greater weight gain at moult than females (means of 8% for females and 17% for males). Biomass of male lobsters increased by up to 16% in one trial treatment, where growth of individual lobsters more than compensated for weight loss caused by mortality. Two different levels of carotenoid (0.15% and 0.25%) proved sufficient to maintain and/or improve colour. Where females were held separate from, but adjacent to, males there was some spawning activity (up to 14%). The one negative outcome of the study was that tail fan damage was found to be a major problem, occurring in both trials and across all diets without apparent pattern. The causes and management of tail fan damage need to be addressed before a long‐term live‐holding industry can be developed. However, in terms of survival and weight gain, results were very encouraging as improvements in pellet formulation, pellet production, and food delivery can be expected.

Effect of reproductive state and sex on movement and food consumption of western rock lobster (Panulirus cygnus) in a tank environment - Kris Waddington; Roy Melville‐Smith; Diana Walker; Brenton Knott (New Zealand Journal of Marine and Freshwater Research, 2005)
The catchability of western rock lobsters (Panulirus cygnus) during the spawning season (October and November) may be affected by their reproductive state. In this study, movement and food consumption of males and females of different reproductive states held in laboratory tanks were measured as proxies for catchability. Density of lobsters was found to influence both movement and food consumption. Solitary animals and, to a lesser extent, two lobsters per tank, were more sedentary and consumed significantly less food than animals at a density of three or four specimens per tank. Tests using three animals per tank confirmed that mature, unmated, and ovigerous females carrying early stage eggs moved more frequently away from their shelters than males or females carrying late stage eggs (P 0.0001, d.f. = 3). Further, unmated females and females with early stage eggs recorded significantly higher food consumption (P 0.0061, d.f. = 3) compared with males or females carrying late stage eggs. The greater time spent away from shelter and also food consumption make unmated females and females with early stage eggs likely to be more catchable than males or females with late stage eggs. As catchability is commonly used to obtain population estimates from survey data, these results have implications for surveys which use catch rates of breeding animals as indicators of egg production.

Moulting behaviour responses of Bay lobster, Thenus orientalis, to environmental manipulation - Satoshi Mikami (New Zealand Journal of Marine and Freshwater Research, 2005)
Bay lobster, Thenus orientalis, locally known as Moreton Bay bug, is being investigated for aquaculture, and controlling the moulting process is critical to success in the production of softshell animals. Identification of moult stages is possible because of the existence of exoskeleton ecdysial sutures (crack lines) on the gill chambers. The timing of moulting is synchronised and occurs around sunset when animals are under a natural day‐night condition. The timing and synchrony of moulting can be manipulated by altering the day‐night cycle, whereas the length of the actual moult stage can be shortened/prolonged by manipulating temperature. During the intermoult stage for juveniles (average weight 79 g), body weight increases only by 9%, whereas the majority of weight gain (an additional 44%) occurs within the short period just before and after the actual moult stage. These findings have application for the development of “softshell” products, which can be harvested at around the actual moult stage.

Movement patterns of the southern rock lobster, Jasus edwardsii, off South Australia - Adrian Linnane; Wetjens Dimmlich; Tim Ward (New Zealand Journal of Marine and Freshwater Research, 2005)
Movement patterns of the southern rock lobster Jasus edwardsii were determined from 14 280 tag‐recapture events across South Australia between 1993 and 2003. In total, 68% of lobsters were recaptured within 1 km of their release site and 85% within 5 km. The proportion of lobsters moving >1 km in marine fishing areas (MFAs) ranged from 13% to 51%. Movement rates were noticeably high in the south‐east and at Gleesons Landing lobster sanctuary off the Yorke Peninsula but patterns of movement differed spatially. In the south‐east, lobsters moved distances of 100 km from within the sanctuary to sites located on the north‐western coast of Kangaroo Island and the southern end of Eyre Peninsula. In total, 85% of all lobsters released inside the sanctuary moved distances >1 km. Movement was highest in immature females within most MFAs. Females also remained at large an average of 124 days longer than males. The high variation in lobster movement observed across South Australia highlights the need for locally derived, regionally specific data when assessing the proposed location and subsequent modelling of marine protected areas. This is of particular importance to inshore areas, where movement rates of lobsters were highest.

Increased predation of juvenile European spiny lobster ( Palinurus elephas ) in a marine protected area - David Díaz; Mikel Zabala; Cristina Linares; Bernat Hereu; Pere Abelló (New Zealand Journal of Marine and Freshwater Research, 2005)
One of the aims of Mediterranean marine protected areas (MPAs) is to increase populations of exploited species, such as the European spiny lobster ( Palinurus elephas ) , which is considered a key species for its commercial and ecological value. Monitoring of temporal patterns in abundance of early benthic stages of P. elephas indicated that predation may be higher inside the Medes Islands MPA relative to adjacent control sites. Tethering experiments were performed to test whether predation rates actually differed within and outside the MPA. Relative mortality of recently‐settled juveniles inside the MPA was much higher than in control sites in adjacent non‐protected areas. Treatments with and without shelter indicated that predation on recently‐settled juvenile spiny lobsters was moderated by the availability of suitable shelter. The decline or absence of fish predators in the fished area may be the reason why juvenile lobsters outside the MPA experience lower predation than within the MPA.

Effects of trap‐shape, bait, and soak‐time on sampling the eastern rock lobster, Jasus verreauxi - S.S. Montgomery (New Zealand Journal of Marine and Freshwater Research, 2005)
It is important when analysing catch and effort information from either fishery‐dependent or fishery‐independent sources, to understand how external factors influence catches so that data can be standardised to be more representative of the abundance of the target species. In New South Wales, Australia, commercial fishers primarily use trapping as the method to capture the eastern rock (spiny) lobster (Jasus verreauxi) and consider trap‐shape, bait‐type, and soak‐time to be the most important factors affecting their catches. Two experiments were done to test hypotheses about the influence of these factors upon catches of lobsters on inshore grounds ( J. verreauxi, it is recommended that: (1) groups of rectangular traps be set as a single replicate to saturate a defined area; (2) as many replicates as practically possible be included; (3) any of the bait‐types described in this paper be used; and (4) the soak‐time for the gear be one day.

Remote multi‐camera system for in situ observations of behaviour and predator/prey interactions of marine benthic macrofauna - David J. Mills; Gerald Verdouw; Stewart D. Frusher (New Zealand Journal of Marine and Freshwater Research, 2005)
There are few options for obtaining information on intra‐ and inter‐species behavioural interactions between marine animals other than direct observation. Underwater video and infrared lighting can be used to overcome some of the biases and limitations associated with diver observations. We outline the assembly and application of a multi‐camera underwater video system consisting largely of moderately priced components produced for the security surveillance industry. Signals from up to eight cameras on the seafloor are processed on a floating pontoon into a single video stream and transmitted to a remote monitoring station for viewing or recording. High‐red and infrared lights are used for night viewing to minimise disturbance. Experiments incorporating this system have provided high‐quality data on predation and behaviour of lobsters.

Effect of physical disturbance on reproductive performance in the spiny lobster, Jasus edwardsii - Greg G. Smith; Arthur J. Ritar (New Zealand Journal of Marine and Freshwater Research, 2005)
A study was conducted to examine the effects of physical disturbance on Jasus edwardsii spiny lobster broodstock during ovarian recrudescence through to larval hatch. Undisturbed brood‐stock were held in relative isolation and subjected to minimal human disturbance, which contrasted with weekly air exposure and handling of the disturbed animals. Broodstock behavioural response, phyllosoma number, competency, and survival in culture were examined. A higher proportion of broodstock from the undisturbed treatment were active during daylight hours compared with those in the disturbed treatment. All ovigerous females in the undisturbed group produced phyllosoma larvae compared with 72.7% of animals in the disturbed treatment. Individual undisturbed females produced greater numbers of phyllosoma larvae, which in turn performed better in larval competency tests, were larger at hatch, and survived better in culture than those from disturbed females. This study demonstrated that physical disturbance altered reproductive performance and larval competency of J. edwardsii. Protocols are suggested to minimise disturbance associated with handling in crustacean broodstock.

Use of fishery‐dependent data for the evaluation of depensation: Case study involving the predation of rock lobster ( Jasus edwardsii ) by octopus ( Octopus maorum ) - Cass M. Hunter; Malcolm Haddon; Keith J. Sainsbury (New Zealand Journal of Marine and Freshwater Research, 2005)
The relationship between the level of octopus ( Octopus maorum ) predation and the daily‐average number of lobsters ( Jasus edwardsii ) per pot was investigated using commercial catch statistics. Octopus predation was found to be inversely correlated with lobster catches, such that, lobsters experienced reduced survival when their daily‐average density in a pot was lower. The reduction in survival at lower densities provides evidence for a depen‐satory mechanism underlying the predator‐prey interaction between pot‐caught octopus and lobster. The effect of lobster density on the feeding response of octopus is unknown so this study could not determine whether depensation was brought about by either predator saturation or predator avoidance tactics used by lobsters. The use of commercial catch statistics to investigate this depensatory effect has disadvantages because the lobster mortality estimates can be biased by the non‐reporting of undersized lobsters caught inside pots, under‐reporting of lobsters killed by octopus, the inability to identify unsuccessful predation attempts made by octopus, and the ability of some lobsters to escape from pots. All the sources of bias would tend to make it difficult to conclusively determine both the absolute proportion of lobsters killed by octopus and the true scale of the depensatory mortality, as the scale of the mortality may be greater than the commercial data suggest. However, the bias will not necessarily reduce our ability to detect the depensatory effect if, as seems likely, the sources of bias are relatively constant across the range of daily‐average catches. Depensation in crustacean stocks affected by pot‐related octopus predation has been rarely studied, and, because depleted stocks lead to fewer lobsters being caught per pot, such depensatory mortality has implications for the population dynamics and management of crustacean stocks.

Reproductive cues in Panulirus ornatus - N.G. Sachlikidis; C. M. Jones; J. E. Seymour (New Zealand Journal of Marine and Freshwater Research, 2005)
Two experiments were performed to assess the effect of photoperiod and temperature on spawning of Panulirus ornatus. In experiment 1, sexually mature lobsters taken from the wild during summer were held at one of two photoperiods, winter (13 Light: 11 Dark) and summer (14.5 Light:9.5 Dark). Additionally, lobsters were also exposed to either summer (29°C) or winter (24°C) average water temperatures. Spawning was significantly greater when animals were exposed to summer photoperiod than to winter photoperiod, irrespective of temperature. Although a higher percentage of lobsters spawned when placed under a higher temperature, this trend was not statistically significant. In experiment 2, sexually mature lobsters were taken from the wild during winter and exposed to the same two photoperiods as in experiment 1, at a summer equivalent temperature of 29°C. Breeding started earlier and was more successful at the summer photoperiod. Time to first breeding was 17 weeks after exposure to summer photoperiod, compared with less than 1 week in experiment 1, and did not occur until individuals had moulted. Moulting occurred in 81% of lobsters, primarily after an increase in temperature to 29°C. The time between moulting and mating was varied and there was no significant difference in moult frequency between the two experimental photoperiods. After the lobsters had moulted, breeding success was reached earlier if photoperiod was lengthened. Results suggest photoperiod is the primary cue for the onset of gonad maturity and mating activity, with temperature playing a less important role. Physiological rest and possibly a moult may be required between breeding seasons before spawning can occur. Furthermore, temperature may be an important cue for pre‐reproduction moulting.

Development and metabolic rate of stage I spiny lobster (Jasus edwardsii) larvae under constant and fluctuating salinities - Michel Bermudes; Arthur J. Ritar (New Zealand Journal of Marine and Freshwater Research, 2005)
The effects of fluctuating salinity on the development and metabolic rate of stage I Jasus edwardsii larvae were investigated. J. edwardsii larvae were reared from hatching through to stage II under continuous salinity regimes at 28, 31, 34, and 37 psu, and under repeated exposure to 28, 31, and 37 psu from a salinity of 34 psu. Continuous exposure to salinities between 28 and 37 psu did not affect the duration of larval development. In the repeated exposure treatments, only larvae subjected to 28 psu developed slower than those in the 34 psu continuous exposure group. Although post‐moult growth to stage II was not suppressed by fluctuating salinity in the 31 and 37 psu groups, larvae repeatedly exposed to 28 psu and larvae under continuous salinities of 28, 31, and 37 psu were significantly smaller than those from the 34 psu continuous treatment. The effect of salinity acclimation on the respiratory response of mid‐stage I larvae was examined in a second experiment. The reduced oxygen consumption of acclimated larvae at subnormal salinities (i.e., 28 psu) was characteristic of stenohaline organisms, and overall there was little relationship between metabolic rate and larval growth performance. From the results obtained in this study we recommend the monitoring and control of environmental salinity for the propagation of J. edwardsii larvae to prevent prolonged exposure to suboptimal salinities.

Development of the red rock lobster, Jasus edwardsii, from egg to juvenile - Jiro Kittaka; Katsuyuki Ono; John D. Booth; W. Richard Webber (New Zealand Journal of Marine and Freshwater Research, 2005)
Mature red rock lobster, Jasus edwardsii were air freighted from the North Island, New Zealand to Japan in 1985. During most years since, egg extrusion has taken place during November and December and egg hatching from February to April. In the main experiment, phyllosomas were cultured in 100‐litre containers. Each container had an upwelling system, connected either to a Nanno‐chloropsis culture tank (Experiment 1) or to a coral sand filter tank (Experiment 2). Artemia nauplii and mussel gonad were the main foods provided. The numbers of 1st, 5th, and 15th instars were 12 000, 1500, and 137 respectively in Experiment 1, and 1500, 99, and 67 in Experiment 2. The intervals between Instars 1–4 and 4–14 were 43 and 175 days respectively for Experiment 1, and 43 and 169 days for Experiment 2. In Experiment 1, nine phyllosomas (13–15th instar) died during metamorphosis to the puerulus and a single 17th instar metamorphosed 303 days after hatching, 19 days later moulting into the juvenile. In Experiment 2, six 17th instar larvae metamorphosed 293 days and more after hatching, with all dying over the following 3 days. In an ancillary experiment, 30 phyllosomas were cultured in each of two 30‐litre tanks containing microalgae: survival was higher, 20% and 43% reaching Instars 14/15 and six metamorphosing after 212–274 days. In all experiments, the developmental sequence was generally consistent with that for larvae from the field. Gill buds appeared at the 13th instar and gills were complete at the 17th instar. Improved culture methods are required to reduce late‐stage mortalities.

Seasonal variations in chemical response to conspecific scents in the spotted spiny lobster, Panulirus guttatus - Patricia Briones‐Fourzán; Enrique Lozano‐Álvarez (New Zealand Journal of Marine and Freshwater Research, 2005)
Chemical response to conspecific scents mediate aggregations in some species of spiny lobsters, but patterns of codenning of adult lobsters in their natural habitats vary widely. This is so for Panulirus guttatus, a small, sedentary, obligate reef‐dwelling species with a protracted, almost year‐round reproductive season. We hypothesised that changes in patterns of aggregation may vary with the intensity of reproductive activity in the population, which in turn may cause changes in responses to conspecific scents. To test this hypothesis, we conducted three laboratory experiments with Y‐mazes to test for seasonal variations in gender‐related and size‐related response to conspecific scents in mature P. guttatus. When reproductive activity (RA) was high (experiment High‐RA, 67.4% reproductive females), males responded significantly to scents of conspecifics of both genders, but females only to the scent of females. When reproductive activity had not yet reached its yearly lowest point (experiment Medium‐RA, 50.0% reproductive females), only females responded significantly to scents of other females, and when reproductive activity was at its lowest (experiment Low‐RA, 4.8% reproductive females) no treatment yielded significant responses. However, results of the size‐related treatments showed that only large individuals responded significantly to scents of other large lobsters during the High‐RA experiment, whereas during the Medium‐RA only small individuals responded to scents of both small and large lobsters. These results are in accordance with previously observed size‐dependent reproduction in P. guttatus over the protracted reproductive season. Therefore, chemical response to conspecific scents in P. guttatus vary with season, gender, and size and may influence co‐denning patterns of mature individuals in the reef habitat.

Captive breeding of the spiny lobster, Panulirus homarus - M. Vijayakumaran; T. Senthil Murugan; M. C. Remany; T. Mary Leema; J. Dilip Kumar; J. Santhanakumar; R. Venkatesan; M. Ravindran (New Zealand Journal of Marine and Freshwater Research, 2005)
Captive broodstock of the spiny lobster, Panulirus homarus, mated successfully and produced more than 105 spawnings over 4 years. Improvements in nutrition and rearing conditions increased the number of spawnings from less than 2, to 4 per year. A single breeder mates three or more times in a year and may spawn more than once following a single mating. An average of four repetitive spawnings per year was recorded. One third of the females spawned 5 times and a single female spawned 7 times in one year. The phyllosoma were released in one or two batches on successive days. The number of phyllosoma larvae released varied from 16 000 to 529 180 with breeder weights ranging from 218 to 696 g.

Invited review - Bruce F. Phillips (New Zealand Journal of Marine and Freshwater Research, 2005)
Lobsters are the focus of very valuable fisheries, and mainly because of this are among the most researched animals on earth. There is a continuing and expanding need for their further study because of changing areas of public interest in their biology and management. They are used as animals for teaching students in a wide range of disciplines, and are species of considerable community interest. The range of scientific studies of lobsters includes: larval ecology, juveniles, behaviour, genetics, stocks, fishing gear and effects of fishing, recreational fishing, disease, post‐harvest practices, economics, triple bottom line reporting, aquaculture and enhancement, eco‐labelling and certification, ecosystem management, and marine protected areas. Examination of important research questions identified at workshops held at previous lobster conferences indicates that some of these questions are being addressed, but in many instances new priorities for research have occurred because of developing technology in the fishery, increasing recreational fishing, disease, changing catch levels; as well as political developments such as marine protected areas, and changing and continuous demand for new or expanded data sets to address new issues such as eco‐labelling. Dissemination of information about lobsters to a wide audience has resulted in a range of methods to achieve better communication including scientific papers, popular magazine articles, fishing magazine articles, and scientific and popular books and films.

Review - Gro I. Van Der Meeren (New Zealand Journal of Marine and Freshwater Research, 2005)
Release of hatchery‐reared lobsters is often suggested for enhancing recruitment‐limited populations. Because of lack of ecological considerations ahead of the releases and the unsuccessful efforts to find juvenile lobsters in the sea, little has been known about survival rates, ecological impacts of the releases, and how to improve the performance of releases. Recent studies of morphology and behaviour in hatchery‐reared Homarid lobsters demonstrate that qualitative, small‐scale laboratory experiments, in combination with larger‐scale field studies can yield such information. This is a review of studies of rearing conditions, transportation, and handling during release that aimed to diminish the occurrence of conspicuous morphology and behaviour in the reared juveniles, causing reduced competitive ability, slow sheltering speed, and thereby high mortality rates in the sea. We need to combine small‐scale studies with field studies to be able to confirm the significance of the laboratory results. Based on significant results from the laboratory, we should be able to design field studies with focus on expected ecological “bottlenecks” instead of the trial‐and‐error‐type field studies known from the past, thereby reducing time and investment in the development of viable stock enhancement/sea ranching activities.

Fate of discards from deep water crustacean trawl fishery off the south coast of Portugal - Margarida Castro; Artur Araújo; Pedro Monteiro (New Zealand Journal of Marine and Freshwater Research, 2005)
Trawling for crustaceans takes place on the south coast of Portugal at depths between 200 and 800 m. Large amounts of discards are released back to sea, reaching the bottom in the general area where trawling occurs. The objective of this work was to study the time taken for decomposition of the discards, to identify the most important scavenging species involved, and to evaluate the impact on the species targeted by the fishery. We conducted a series of 22 trials, using traps baited with samples of the discards. The time of immersion varied between 1 and 40 h. The amount of tissue removed from the discards was evaluated on a qualitative scale of 1–3, and quantitatively. The species caught in the traps were identified. Considerable consumption of the bait had occurred after 5 h of immersion. After 24 h of immersion only fish bones were left; past 40 h, consumption was complete. The conger eel ( Conger conger ) was the most common fish species present in the traps. Two species, the amphipod Scopelocheirus hopei and the isopod Natatolana ( Cirolana ) borealis, were identified as most important for the recycling of organic matter in the system. The stomach contents of a sample of species caught in trawls were analysed for the presence of small scavengers. Preliminary results show that S. hopei and N. ( C. ) borealis are part of the diet of some of the target species of this fishery, such as the Norway lobster, Nephrops norvegicus and the rose shrimp Parapenaeus longirostris.

Causes of tail fan necrosis in the southern rock lobster, Jasus edwardsii - Richard J. Musgrove; Michael C. Geddes; Connor Thomas (New Zealand Journal of Marine and Freshwater Research, 2005)
Tail fan necrosis (TFN) is a recognised constraint on the advancement of the South Australian rock lobster (Jasus edwardsii) liveholding industry because of a reduction in value of afflicted lobsters. Trials were run in the laboratory and at a shore‐based experimental live‐holding facility (LHF) to determine the influence of at‐sea post‐harvest handling, feeding frequency (LHF only), density (LHF only), and temperature (laboratory only) on the advent of the condition. Lobsters were caught during normal fishing operations and either immediately placed in protective fine‐mesh nylon bags and stored in the boat's well or placed unbagged in the well. At the laboratory, the tail fans of half the bagged lobsters were deliberately damaged with sterile instruments. At the LHF the TFN level increased significantly over 4 months. The bagged treatment showed significantly less late‐stage TFN than unbagged daily or weekly‐fed treatments with 60% of bagged lobsters showing no TFN at 4 months. With unbagged lobsters, 50% showed erosion in the 25% of the tail fan. Lobster density and feeding frequency had no effect on TFN incidence. In the laboratory, bagged and bagged‐damaged treatments had no advanced TFN after the 6‐week period suggesting that post‐harvest bagging minimises TFN and that inflicting physical damage to lobster tail fans with aseptic instruments does not lead to its development. Temperature had no effect on TFN development. The highest incidence of TFN was found in lobsters given normal post‐harvest handling, that is, communal holding in boat holds and tanks (i.e., without bags). These conditions are normally associated with physical damage inflicted by conspecifics. Such damage will presumably also involve infection of wounds by the bacterial flora of the crayfish exoskeleton, leading to development of TFN.

New tank design for larval culture of Japanese spiny lobster, Panulirus japonicus - Hirokazu Matsuda; Taisuke Takenouchi (New Zealand Journal of Marine and Freshwater Research, 2005)
Middle‐stage phyllosoma of Panulirus japonicus (mean body length 11.5 mm) were cultured using 40‐litre elliptical tanks with concave bottoms (85 cm long × 60 cm wide × 15 cm deep) in a flow‐through system (24–25°C). The phyllosoma were fed with Artemia and mussel go‐nad. Survival rates to the puerulus stage were 54 ± 1%, 51 ± 0%, and 37 ± 9% at densities of 40, 60, and 90 phyllosoma/tank, respectively. The densities did not significantly affect the growth of phyllosoma. Major causes of phyllosoma mortality included moulting complications, bacterial disease, and cannibalism. The survival rates were significantly higher than in our previous studies, indicating that the new elliptical tank design may be suitable for mass culturing of phyllosoma. The survival of puerulus to the first juvenile stage was 83 ± 7% and did not differ between densities during phyllosoma rearing.

Stock enhancement of rock lobsters (Jasus edwardsii): timing of predation on naïve juvenile lobsters immediately after release - Megan D. Oliver; Rob Stewart; David Mills; Alison B. Macdiarmid; Caleb Gardner (New Zealand Journal of Marine and Freshwater Research, 2005)
The success of enhancement programmes hinges on the survival of released animals. One factor greatly influencing short‐term survival of reseeded lobsters is the timing and intensity of predation relative to the time of release. The activity and abundance of predators varies over daily, seasonal, and annual scales and knowing the best time to release juveniles will minimise mortality. We used chronographic tethering devices and remote video equipment at 10 sites near Wellington, New Zealand and Hobart, Tasmania, Australia, to assess the relative timing and intensity of predation for released lobsters. Our studies showed that predation was greatest within the first 2 h after release (χ 2 = 60.425, d.f. = 9, P 0.001) suggesting that the disturbance associated with the release itself may draw the unwanted attention of predators. Relative predation rates also peaked on each of the following two mornings, possibly because of the emergence of daytime predators. The video footage obtained at the Tasmanian sites revealed that most predation was by fish (46%), but surprisingly, cannibalism comprised 16% of predation events. The limitations of tethering as a method are discussed in numerous reviews but proved useful as a relative measure for these highly mobile and cryptic animals. Further consideration needs to be given to methods of release that minimise mortality of recently seeded lobsters.

Dynamics of a 3‐dimensional, baroclinic, headland eddy - Kerry Black; John Oldman; Terry Hume (New Zealand Journal of Marine and Freshwater Research, 2005)
Wave, current, and temperature measurements from the north side of Cape Rodney, northeastern New Zealand, over a 6‐week field programme, reveal the detailed internal dynamics of a baroclinic eddy. The measurements include water levels, currents, and water temperatures through the water column and seabed descriptions. A detailed calibration of a 3‐dimensional numerical model leads to further examination of the flow and density structure within the eddy, in plan and cross‐section. The eddy stretches c. 5 km along the northern side of the headland and is of the order of 1.5–2.0 km wide. The eddy currents are strongest near the bed and against the coast. The eddy is characteristically complex and vertical eddies readily form in parts of the water column during different phases of the tide, although these internal eddies rarely penetrate through the full depth. The dynamics near the surface and near the bed are significantly different and the structure of the eddy is often partitioned vertically and is strongly affected by wind.

Reproductive biology of Holothuria leucospilota in the Cook Islands and the implications of traditional fishing of gonads on the population - Darrin J. Drumm; Neil R. Loneragan (New Zealand Journal of Marine and Freshwater Research, 2005)
This study describes the reproductive biology of Holothuria leucospilota in Rarotonga, Cook Islands and assesses the effect of traditional fishing on survival and reproduction. Monthly collections of H. leucospilota from January 1998 until March 1999 revealed that gametogenesis and spawning were synchronous between the sexes and spawning occurred annually during the summer months. Spawning during the first year had already started at the beginning of the study in January and lasted until April, whereas in the second year, spawning started in November and finished in February, possibly because of higher water temperatures in this year. Our data indicate that the incision of the body‐wall and gonad removal had no impact on the survival of H. leucospilota in cages. However, their body weight, general sheltering and feeding behaviours were affected by gonad removal. Although the body‐wall of fished animals healed within 7–14 days, the gonads had just started to regenerate after 41 days, suggesting that the spawning of fished individuals would have been greatly delayed, possibly until the following year.

Longitudinal patterns in benthic communities in an urban stream under restoration - Tanya J. Blakely; Jon S. Harding (New Zealand Journal of Marine and Freshwater Research, 2005)
Okeover Stream, on the University of Canterbury campus in Christchurch, New Zealand, has been the subject of restoration efforts since 1998. Our study focused on quantifying the response of this urban stream to current restoration efforts. Initially, physico‐chemical conditions and biological communities at three sites along the Okeover Stream were compared with three physically similar sites on each of nearby Waimairi Stream and Avon River. General physical and chemical parameters were similar in all streams with circum‐neutral pH, specific conductivity ranging from 167 to 173 μS/cm, dissolved oxygen ranging from 9.0 to 9.2 mg/litre, low turbidity, and similar hydrological conditions. However, analysis of heavy metals in the sediment showed mean lead (Pb) concentrations in Okeover and Waimairi Streams exceeded ANZECC ISQG‐low trigger values (86.9 and 83.7 mg/kg, respectively), whereas Avon River sediment Pb levels (27.3 mg/ kg) were below trigger values. Benthic taxonomic richness did not differ significantly among the three streams. However, Okeover Stream community was dominated by the amphipod Paracalliopefluviatilis, whereas in Waimairi Stream and Avon River the gastropod snails Potamopyrgus antipodarum and Physella acuta were the dominant benthic fauna. A further assessment made at six sites along 1200 m of Okeover Stream showed no distinct longitudinal patterns in physical or chemical conditions, but there was a strong pattern in benthic macroinvertebrate communities. Taxonomic richness and caddisfly diversity increased downstream, with twice as many taxa at the most downstream site than the uppermost sampling site. In upper reaches, copper (Cu), Pb, and zinc (Zn) concentrations in sediments all exceeded ANZECC ISQG‐low trigger values. Despite ongoing restoration efforts in Okeover Stream, sedimentation, the presence of high heavy metal concentrations, intermittent flows in headwaters, and possible barriers to adult recolonisation seem to be having a continuing negative impact on benthic communities, especially in the headwaters.