Pictured: The Pomahaka galaxiid is found only in the Pomahaka River and its tributaries in South Otago. Photo: Ian Hadland
A collaboration is unfolding between Otago Fish & Game and Ernslaw One to protect native fish species.
Fish & Game, in partnership with the private forest owner, has undertaken the ambitious task of removing trout from streams in plantation forests where threatened native fish require protection and there is little sports fishing value.
Otago Fish & Game Council chief executive Mr Hadland said a headwater tributary of Crookston Burn, in the Blue Mountains near Tapanui, held a remnant population of rare Pomahaka galaxiids.
Trout had entered the tributary following flood damage to a culvert which had acted as a fish barrier and previously protected the native fish population.
After the culvert was repaired, eDNA testing by Ernslaw One revealed trout had migrated upstream. The forestry company then approached Fish & Game.
Pictured: Otago Fish & Game chief executive Ian Hadland holds a brown trout captured through electric fishing and relocated below a fish barrier on Crookston Burn. Photo: John Hollows
Mr Hadland said Fish & Game electric-fished the creek this month [November 14] to identify native fish extent and remove the brown trout.
"Upstream of the repaired culvert, 25 Pomahaka galaxiids were identified and 85 trout were captured and relocated below the culvert,” Mr Hadland said.
“It’s a challenging site for electric fishing because of the vegetation and steep nature of the creek, but we’re pleased with the result.
"Projects such as this fit with Otago Fish & Game’s species interaction policy. Trout removals are always considered carefully alongside other methods to protect galaxiids and other native species.
“We’re pleased to be working with a private forest owner such as Ernslaw One to protect both native fish and introduced sports fish."
Pictured: Ernslaw One aquaculture manager John Hollows admires a rare Pomahaka galaxiid at Crookston Burn. Photo: Ian Hadland
Ernslaw One aquaculture manager John Hollows said the idea for the project came about when eDNA testing revealed trout had migrated upstream into an area where galaxiids were previously the only fish species present.
Discussions with Otago Fish & Game led to the trout being removed.
Recent research by Fish & Game had identified important trout spawning streams in Blue Mountains plantation forests.
Mr Hollows said the research highlighted the ecological importance of creeks within the company’s plantation forests.
“This initiative is not a standalone effort by Ernslaw One, rather it's a part of a larger biodiversity protection project in our southern plantation forests,” he said.
“The goal is not only to safeguard native fish but also to create a holistic environment where diverse flora and fauna can coexist harmoniously within a plantation forest setting.”