Spatio‐temporal distribution of fish in the Kakanui River estuary, South Island, New Zealand

Abstract

The fish community of the Kakanui River estuary on the east coast of the South Island, New Zealand, was studied seasonally over 1 year by diel seine netting and nocturnal fyke (trap) netting. Twenty species were recorded, although nine of these together constituted 0.2% of the total number of fish caught. Marine species were represented by single individuals of four species. Brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) were the only species without an obligatory marine life‐history phase. Small benthic fishes, cockabullies (Tripterygion nigripenne), and common bullies {Gobiomorphus cotidianus) were the numerically dominant species and, together with a further nine species, were resident year‐round. Winter was the season of lowest abundance of most species. Spatial patterns of distribution were apparent with common bullies, giant bullies (G. gobioides), and longfinned eels (Anguilla dieffenbachii) occurring mainly in the upper estuary; common smelt (Retropinnna retropinna) mainly in the lower estuary; and cockabullies, yelloweyed mullet {Aldrichetta forsteri), and shortfinned eels {Anguilla australis) present throughout the estuary.