Motivation Freshwater ecosystems have been heavily impacted by land‐use changes, but data syntheses on these impacts are still limited. Here, we compiled a global database encompassing 241 studies with species abundance data (from multiple biological groups and geographic locations) across sites with different land‐use categories. This compilation will be useful for addressing questions regarding land‐use change and its impact...

Knowledge of stock structure is key for the effective management of any fish species. Amphidromous fish, which live and spawn in freshwater but spend a pelagic larval period at sea, have typically been assumed to disperse widely during their larval phase, resulting in populations being sourced from a single unstructured larval pool. We used otolith microchemical analysis to examine the stock structure of bluegill bully ( Gobio...

Invasive fish eradication is a key management strategy in aquatic ecosystems, and is often accomplished using piscicides such as rotenone. However, the effects of piscicides on aquatic invertebrate communities are poorly understood, particularly over long time scales. We monitored invertebrate communities in two treatment and two reference streams prior to and for one year following the use of rotenone to eradicate trout in Ze...

The larval stage of fishes is critical in determining their dispersal, survival and recruitment, but little is known of the larval behaviours and tolerances of amphidromous fishes, particularly in New Zealand. We report the results of a series of observational and experimental studies on bluegill bully ( Gobiomorphus hubbsi ), including spawning sites and behaviours, larval characteristics at hatch, phototactic responses of la...

While many of New Zealand’s freshwater fishes undertake larval migrations as part of their amphidromous life‐history, little is known of the larval stages of these fish. Torrentfish ( Cheimarrchthys fosteri ), a New Zealand endemic, amphidromous, riffle specialist are particularly enigmatic; their spawning sites and behaviours are unknown, and larvae have never been collected either emigrating from freshwater or during their m...

Using a space‐for‐time substitution design, we investigated the response of structural instream habitat and fish populations to different riparian management practices throughout a Dairy Best Practice Catchment. We found a significant negative correlation between the upstream area of stock exclusion fencing and deposited instream fine sediment cover. Furthermore, we determined that this relationship emerges when ≥300 m lengths...

An investigation of intraspecific habitat‐related patterns of variation in oculoscapular lateral‐line superficial neuromasts ( SN ) identified a decrease in the ratio of total SNs to pores, and a trend towards decreased asymmetry in SNs in the habitat‐generalist common bully Gobiomorphus cotidianus from fluvial habitats compared to lacustrine habitats, suggesting habitat‐related phenotypic variability. A greater ratio of pores...

The temporal stability of trace element concentrations in fertilized, artificially incubated anadromous brown trout Salmo trutta eggs and newly hatched fry was investigated. The anadromous status of the parental fish was confirmed using strontium isotopic analysis of otoliths. Whilst manganese concentrations in eggs varied over time, concentrations of aluminium, potassium, magnesium, strontium, barium and calcium were all unch...

The otoliths of laboratory‐reared larval and juvenile perch Perca fluviatilis of known age were analysed to determine the age of otolith formation and validate the formation of daily increments. There was a linear relationship between number of increments and age in days post‐hatching, although by 82 days post‐hatching daily increment counts underestimated actual age by an average of 5 days. Otolith dimensions in relation to s...

The relationship between the strontium content of the outer layers of otoliths (an indication of recent marine, estuarine or riverine habitat use) and the strontium content of roe in ripe female brown trout Salmo trutta was examined in fish collected from the Pomahaka River and the lower reaches of the Clutha River, South Island, New Zealand. A close relationship was found between the strontium content of roe and the outer lay...

Direct counts of fish obtained by night spotlighting were compared with species composition and population estimates obtained from three‐pass electrofishing obtained across 29 sites along small clear streams in the Otago region of New Zealand. The influence of habitat variables on the relative efficiency of each method was also examined. The same seven species of fishes were identified by both methods. Juvenile brown trout Sal...

Histological analysis of the skin of common bully Gobiomorphus cotidianus , a New Zealand native eleotrid fish, revealed the presence of club cells in the epidermis. Epidermal club cells are frequently associated with the production of alarm substance (Schreckstoff). The behavioural responses of perch‐naïve and perch‐experienced common bullies to either conspecific skin extract or chemical cues from an introduced predator, per...

Visible implant elastomer (VIE) was evaluated as a method for individual marking of small perch Perca fluviatilis and common bully Gobiomorphus cotidianus to use in capture–recapture studies. Growth, survival and mark retention was measured in 25 VIE marked and 15 unmarked fish of each species during a 125 day laboratory experiment. Marking had no effect on growth or survival of either species and mark retention in perch was 1...

Nocturnal microhabitat selection in relation to size was examined for a New Zealand drift‐feeding freshwater fish, the giant kokopu Galaxias argenteus in three coastal Otago streams. Evidence for ontogenetic shifts in microhabitat selection were observed, particularly with respect to water velocity and depth. Small (

Fyke nets were used to sample longfin eels Anguilla dieffenbachii in fourth order stream sites with contrasting riparian land use (native tussock, exotic pasture and pasture plus willows Salix spp.) in Lee Stream, a tributary of the Taieri River, New Zealand. Total lengths ( L T ) of longfin eels from locations inaccessible to eel fishers were normally distributed whereas those from accessible locations had a non‐normal, posit...

In times of biodiversity crisis there is an increasing need for faster and cheaper methods by which to achieve conservation goals. This situation is especially troublesome for invertebrates, and the use of morphospecies instead of taxonomic species has been proposed as a way around the taxonomic constraints in particular situations. We conducted a study in a modified native shrubland on New Zealand's South Island in which we s...

Longfin eels Anguilla dieffenbachii caught by electrofishing, in Lee Stream, a tributary of the Taieri River, New Zealand, were significantly longer in pools than in riffles, particularly in summer. Longfin eels were generally shorter in sites with willow. More longfin eels were caught at pasture sites than tussock sites with fewest at sites with willow. Sites judged difficult to access by commercial fishermen had longfin eels...

Signal strength received by a fixed antenna increased as a transmitter was positioned closer to it and decreased as the transmitter was positioned further away. Depth and transmitter orientation also influenced signal strength, but these were less pronounced than the effect of distance. The variations in signal strength recorded from fixed distances, depths or orientations were low, suggesting that variation in signal strength...