Suspended sediment (SS) is an important pollutant in freshwater ecosystems and can be detrimental to fish communities. Although macrophytes mediate sediment deposition, little effort has been put into determining how their removal affects sediment resuspension. The present study examined the immediate and long‐term impacts of mechanical macrophyte removal on SS concentrations in streams. The results of this study suggest that...

Mysids form a large biomass and mediate the benthic–pelagic coupling of numerous estuaries in southern New Zealand. An intra‐annual (2011–2012) field survey in the breeding seasons (i.e. austral spring followed by summer) of mysids Tenagomysis chiltoni and Tenagomysis novaezealandiae , examining the body and brood sizes, was conducted. Samples were collected from six open and eight intermittently open/closed estuaries along th...

Amphidromy is a distinct form of diadromy, involving a downstream migration (‘drift’) to a pelagic feeding habitat undertaken by exceptionally small, undeveloped larvae immediately after hatch. Identifying patterns of larval drift may indicate critical periods within which conservation measures can be targeted to protect migrating larvae. This study utilised diel and spatial drift sampling to examine patterns of larval drift i...

Mysids Tenagomysis chiltoni and T. novaezealandiae are abundant in southern New Zealand estuaries. Size‐specific oxygen consumption rates of adult females of T. chiltoni and T. novaezealandiae were measured under salinities 0–1, 5, 10, 15, 20, 25, 30 and 33–34 at 5 °C and 20 °C in relation to body size. We predicted that, irrespective of salinity variations, the larger individuals would show lower size‐specific oxygen consumpt...

Sediment resuspension during and after mechanical excavation of macrophytes may have a significant impact on resident fish populations. Unfortunately, little is known about the influence of this sediment on the respiratory performance and feeding abilities of fishes in New Zealand waterways. We examined the effects of suspended sediment (SS) concentrations previously observed after a large‐scale macrophyte removal operation on...

This study examined whether element:Ca ratios within the otoliths of juvenile brown trout could provide accurate trace element signatures for specific natal tributaries, and attempted to match these to trace element natal signatures found within the otoliths of adult trout caught in the main stem rivers of the same catchment. The trace element signatures of juvenile trout otoliths were analysed from a sample of eight tributari...

To assess microhabitat selection by banded kokopu ( Galaxias fasciatus ), a total of 215 fish were observed using spotlight along 350 m of Sawyers Bay stream in southern New Zealand. We measured multiple microhabitat variables at the focal point position of each observed fish. A correlation analysis showed that depth, focal velocity, adjacent fastest velocity and substrate were the factors most strongly associated with the fis...

Few studies have compared hyperbenthic communities among estuaries, in either New Zealand or elsewhere. This study presents the results of a single late summer survey of the lower reaches of 26 estuarine systems along the Otago coastline from the Clutha River to Oamaru, comparing hyperbenthic communities among both permanently open and intermittently closed estuaries. Intermittently closed estuaries are periodically closed fro...