First capture and description of larval torrentfish ( Cheimarrichthys fosteri ) during their seaward migration

Abstract

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 marine feeding phase. During summer drift sampling, we captured unidentified fish larvae emigrating downstream in the Waianakarua River, South Island, New Zealand. Based on multiple lines of evidence (meristic comparisons with adults, morphology, time of capture, and adult fish populations of the Waianakarua) we identify these larvae as torrentfish. This represents the first time torrentfish larvae have been captured or identified, laying the foundations for future studies into the early life‐history and ecology of this unique and threatened fish.

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