Rare native fish discovery thanks to Donald Scott Scholarship

New populations of a rare and threatened native fish species have been found in three locations in the Cardrona Valley thanks to research funded by the inaugural Donald Scott Memorial Scholarship in Freshwater Ecology.

The Clutha flathead galaxias, a critically endangered species found only in Central Otago, was detected in two previously unrecorded populations — and a third population rediscovered after 20 years — during a field survey led by Otago-based researcher Isaac Davies.

The project, instigated by a generous donation from Patricia Scott with ongoing support from the Otago Fish & Game Council and Clutha Fisheries Trust, surveyed 30 streams throughout the Cardrona Valley.

Pictured above: Paul van Klink (left) and University of Otago postgraduate student Isaac Davies conduct electrofishing in Coal Creek in the Cardrona Valley during research into Clutha flathead galaxias. Photo: Mason Court

All three populations of Clutha flathead were found in small, trout-free headwaters, highlighting the importance of natural fish barriers in protecting vulnerable native fish.

Mr Davies, a postgraduate researcher at the University of Otago and the inaugural recipient of the Donald Scott Memorial Trust Scholarship, said the discovery adds significantly to understanding species interactions in the region’s freshwater ecosystems.

“The Cardrona remains a valuable sports fishery, but this project shows there’s also room to recognise and protect the special native species still hanging on in remote corners,” he said.

The Clutha flathead galaxias is a critically endangered species found only in Central Otago. Photo: Isaac Davies

While most of the research into the Clutha flathead has been in the Cardrona catchment, field work has also been done in the Nevis, Little Valley near Alexandra, Queensbury, and near Lawrence.

As well as distribution mapping, the research has expanded into the Clutha flathead’s life history — including spawning age, egg size, abundance, and the downstream drift of newly hatched larvae. These insights will help inform how native and sports fish can be managed together in shared catchments.

“The scholarship made it possible to investigate key questions about how this species survives and how to protect it,” Mr Davies said. “Reading about everything Dr Scott contributed to freshwater management in New Zealand made me incredibly honoured to be the first recipient.”

The Donald Scott Memorial Trust Scholarship was established to honour the legacy of the late Donald Scott, a pioneering freshwater advocate. His wife, Pat Scott, played a central role in launching the scholarship fund in 2022 through a generous donation.

"Donald was a Fish & Game councillor for many years and was instrumental in encouraging Fish & Game to bring scientific research into their management of the habitat of sports fish in Otago,” Mrs Scott said.

“The outstanding work in the discovery of these new populations of rare galaxiids by the first scholar of the Donald Scott Memorial Scholarship proves the worth of Fish & Game's ongoing commitment to scientific research and to being kaitiaki of the taiao."  

Otago Fish & Game chief executive Ian Hadland said the research aligned with the organisation’s balanced approach to species management.

“We’re committed to supporting resilient ecosystems that support both native fish and a world-class sports fishery,” he said. “This work, guided by our Regional Species Management and Interaction Policy, shows the value of partnerships in getting there.”

Professor Gerry Closs, from the university’s Department of Zoology, said: “The University of Otago is very grateful to the Scott family, Otago Fish & Game and Clutha Fisheries Trust for supporting our students through this scholarship fund. Supporting students enables these critical discoveries to be made.”

The research also identified priority sites for environmental DNA (eDNA) sampling, which will provide an even clearer picture of where native fish populations remain and how to protect them.

• If you want to support future freshwater ecologists in Otago, please visit otago.ac.nz/donate/DSMS to donate to the Donald Scott Memorial Scholarship in Freshwater Ecology.

Key Findings:

• Three Clutha flathead galaxias populations found — two new, one rediscovered
• All located in trout-free headwaters protected by natural barriers
• 30 streams surveyed across Cardrona Valley
• Additional species recorded: brown and rainbow trout, kōaro, upland bullies, longfin eels
• Research to inform future native and sports fish co-

University of Otago postgraduate student Isaac Davies