New Zealand: Key Otago trout spawning streams identified

Frozen Trout

Seafood

New Zealand

Published Jul 18, 2023

Tridge summary

A four-year research project has identified crucial trout-spawning tributaries in the lower Clutha River/Mata-au catchment. The Brown Trout Origin Project collected and analyzed the ear bones of juvenile and adult trout from around the catchment. The research compared the chemical composition of the otoliths to determine the spawning streams of adult trout, with 71 out of almost 200 fish tested having their spawning streams confidently determined.

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Original content

Crucial trout-spawning tributaries have been identified in the lower Clutha River/Mata-au catchment following a four-year research project collecting and analysing brown trout. The Brown Trout Origin Project analysed the otoliths (ear bones) of juvenile and adult trout collected from around the catchment by Fish & Game and anglers. The catchment extends from below Roxburgh Dam to the sea, including historically renowned trout rivers such as the Pomahaka and Waipahi. Otolith research was completed at the University of Otago using a precise laser and mass spectrometer. The analysis was done this year by Olivier Raven, a visiting master’s student from Wageningen University in the Netherlands. “To best manage the fishery and ensure sustainability, understanding the migratory patterns of brown trout is crucial,” Raven said. “We identified the birthplaces of adult trout caught by anglers in locations often significant distances from where the fish had originated.” The research compared ...

Source: Farmersweekly