Several water quality parameters, marginal vegetation, and the fish community in Lake Ellesmere, a large, shallow, turbid lake situated on the east coast of the South Island, New Zealand, were sampled along selected transects in late summer to determine species spatial patterns. Thirteen species offish were caught, with seven of them comprising major populations, although only four of these were adequately sampled by the metho...

Southern Buller's albatrosses ( Diomedea bulleri bulleri Rothschild) are frequently associated with fishing vessels off southern New Zealand, and may depend substantially on discards from fishing vessels, particularly trawlers, during chick rearing. To test this hypothesis, the diet was determined from 188 chick regurgitations collected at The Snares (May 1996, July 1996 and 1997) and Solander Island (May and July 1997). Fish...

A small‐scale preliminary investigation into the breeding and rearing of the seahorse Hippocampus abdominalis Leeson, 1827 in New Zealand was conducted using 12 wildbroodstock. These broodstock were maintained in a hatchery for breeding and the breeding behaviours exhibited by these were observed and described. Over a period of 6 months a total of 12 broods of juveniles were produced. These were then raised on a diet consistin...

Stages I, III, and V phyllosoma larvae of the rock lobster Jasus edwardsii (Hutton) were fed daily with 40, 80, 160, or 320, 1‐mm brine shrimps ( Artemia salina ) while controls were fed either 4, 8, or 16, 2–3‐mm brine shrimps. Stage I larvae fed 1‐mm brine shrimps moulted in the same time as the controls. Stage III and V larvae fed 160,1 ‐mm brine shrimps or less took significantly longer to moult than the controls but those...

Summer distributions of the crayfish Paranephrops zealandicus White, and of potential predators and prey, were investigated in 30 pools along a stream in Otago, New Zealand. Environmental variables were regarded as independent and invertebrates as dependent variables for young‐of‐the‐year (YOY) and adult crayfish. YOY and adults were negatively associated with trout presence and suspended solid concentrations, and positively w...

Baited branchlines were set from a tuna longlining vessel using an underwater setting device and their sink patterns compared with those of baited branchlines that were hand‐thrown. Using a paired /‐test at an hypothesised mean difference of 2 m, at a point 100 m astern of the vessel, baited branchlines set using the device were significantly deeper than those that were hand‐thrown. Baited branchlines set using both methods sh...

Laboratory experiments demonstrated that migrant juvenile banded kokopu ( Galaxias fasciatus Gray) were more sensitive to suspended sediment (SS) than other native fish species. If juvenile migrants avoid waters made turbid by SS and their recruitment to adult habitats up stream is reduced, then adult abundance may decline in turbid rivers. To test this, we compared the abundance of diadromous native fish between turbid and cl...

Paphies donacina (Spengler, 1793) populations were surveyed at 11 low tide sites on surf beaches along Pegasus Bay, Canterbury, New Zealand, during summer 1998. Random sampling was not feasible. At the non‐random sites chosen the average number of tuatua per 5 m of shoreline ranged between 0.1 and 62. Total wet weight biomass m ‐2 was highest at the southern sites in the Bay. There were site‐related differences in length frequ...

The rare and inadequately‐defined abyssal slickhead, Mirognathus normani Parr (F. Alepocephalidae), is redescribed based on Atlantic material and the first specimen collected from the Pacific Ocean.

Infaunal bivalve molluscs on the flood tidal delta of Tauranga Harbour, north‐eastern New Zealand, were surveyed twice over a 6‐month period, with the aim of assessing shellfish resources, assessing the magnitudes of temporal and spatial variability in abundances, and identifying potentially important processes. The surveys identified a total of 31 bivalve taxa from 27 sites. Species richness per site ranged between 0 and 9, a...

The oxygen (δ 18 O) and carbon (δ 13 C) isotope ratios of 10 species of living Bryozoa collected from the Otago Shelf, New Zealand were analysed to assess the extent to which isotopic equilibrium (relative to inorganic equilibrium isotope fractionation) is attained during the precipitation of skeletal calcium carbonate. The data reveal that whereas eight species of Bryozoa synthesise skeletal carbonate in apparent oxygen isoto...

Abundance and species composition of benthic invertebrate communities were investigated in two rivers of contrasting channel form, the Tukipo and Waipawa, in the Southern Hawke's Bay, New Zealand. Monthly collections between December 1995 and December 1996 yielded a total of 89 taxa from the two sites; Deleatidium spp. numerically dominating the braided Waipawa whereas Pycnocentrodes spp., Pycnocentria funerea, Aoteapsyche spp...

The Stump Bay wetland is part of the South Taupo wetland, situated on the southern coast of Lake Taupo in the central North Island, New Zealand. The water level of Lake Taupo has been artificially controlled since 1941. The present study found that surface and subsurface water levels in the wetland are closely related to each other. These water levels are influenced mainly by rainfall and evapotranspiration (which is seasonal)...

A predictive model of fish community composition using a reference condition approach is proposed for the Taranaki region of New Zealand. The model is used to quantify the effects of barriers on the migration of native fish in the region. Occurrence records of fish in streams without migratory barriers (reference sites) obtained from the New Zealand freshwater fish database were used to establish trajectories of occurrence for...

The influences of leaf characteristics on stream invertebrate communities were investigated to improve the basis for selecting plants for riparian management to enhance stream invertebrate abundance and biodiversity. Invertebrate colonisation of leaves of five native and five exotic riparian plants were compared over 4 months in field experiments in a New Zealand pasture stream and adjacent channels, and laboratory experiments...

A new name is proposed for the relatively cool, fresh, northwards‐directed flow along the Wairarapa coast of New Zealand. Data from two research cruises plus historical hydrocast dam are used to show that the water within this current is modified subtropical water with sources likely to be the Southland and D'Urville currents. This current has previously been known as the Canterbury Current or as an extension of the Southland...

Ostreopsis siamensis and Coolia monotis (Ostreopsidaceae) are newly recognised additions to New Zealand's toxic marine microflora and occur epiphytically on seaweeds throughout subtropical New Zealand. O. siamensis “blooms” during summer, becoming freely motile; it tolerates temperatures of 15–25°C and salinities of 28–34 ppt. C. monotis also occurs in sediments in Nelson/ Marlborough and Stewart Island, at 10–30°C and salinit...

For two key New Zealand freshwater invertebrates (the mayfly Deleatidium autumnale and the snail Potamopyrgus antipodarum ) the upper thermal tolerances were measured in the laboratory under both constant and diumally varying temperatures. At constant temperature 50% mortality in 96 h ( const LT 50 ) occurred at 24.2 ± 0.9°C for mayflies and 31.0 ± 0.6°C for snails: values similar to previously published estimates (Quinn et al...

The factors influencing in‐stream disintegration and uptake of dissolved nutrients by leaves were investigated to improve the basis for selecting plants for riparian management. Leaves from five introduced and five New Zealand native plants were studied in 12 streamside channels and a natural stream. Fallen, air‐dried leaves were tethered in packs attached to tiles in the channels and stream, and measured for mass loss, nitrog...

Epipelagic juvenile bluenose, Hyperoglyphe antarctica (Carmichael 1818), are recorded from New Zealand for the first time. Two specimens were collected beneath flotsam nearNga Motu/Sugar Loaf Islands, west coast North Island in September 1996, and at least 20 were found inside a piece of trawl net drifting east of Cape Kidnappers, east coast North Island in September 1997. Live specimens between 65 and 87.3 mm standard length...

Aquatic macroinvertebrates were sampled annually at 66 sites of the National Rivers Water Quality Network (NRWQN) from 1989 to 1996. At each site, temporal trends in number of taxa, total abundance, Macroinvertebrate Community Index (MCI), the quantitative version of MCI (QMCI), number and percent of Ephemeroptera, Plecoptera, and Trichoptera, Shannon's Diversity Index (H'), Jaccard's similarity index, and Bray‐Curtis similari...

Stream managers often need to predict the impacts of high and time‐varying temperature on key stream invertebrates. A simplified model has been developed and calibrated using mortality observations made at constant temperature for two important New Zealand stream invertebrates: the snail Potamopyrgus antipodarum and the mayfly Deleatidium autumnale . A close fit was obtained for Deleatidium but Potamopyrgus showed evidence of...

Predominant features of barotropic and baroclinic circulation and mixing in the Hauraki Gulf on New Zealand's north‐east coast are described using measurements and 3‐dimensional numerical model simulations. Circulation in the Hauraki Gulf is strongly 3‐dimensional with a primary dynamical balance between surface wind stress and the associated pressure gradients against the land. This leads to persistent up/downwelling and surf...