Urgent call to fence off Kosciuszko creek to save endangered fish

The remaining habitat of a critically endangered freshwater fish in the Kosciuszko National Park needs to be fenced off urgently to protect it from feral horses, scientists and campaigners say.

A three-kilometre stretch of the Tantangara Creek is the only place known to harbour the stocky galaxias, a fish that was described as a distinct species only five years ago.

The stocky galaxias is a critically endangered freshwater fish in Kosciuszko National Park.Credit: University of Canberra

The National Parks and Wildlife Services said it has been discussing with the University of Canberra ways the fish and its environment can be protected. "Fencing may be one option," a spokesman said.

Mark Lintermans, a fisheries ecologist with the university, said invasive trout had reduced the galaxias' range to a short stretch of the creek.

However, rising numbers of brumbies meant there were now about 50 crossings on that section.

"It's only going to get worse," Associate Professor Lintermans said, estimating the cost of fencing at $60,000.

The horses stir up fine sediment in the water, which smothers the insects that the fish feed on.

Worse, fewer of the fish's eggs survive because the sediment either smothers the eggs - preventing them from breathing - or it reduces the ability of the eggs to stick to the underside of rocks to grow so they get washed away instead, he said.

Last year, the Berejiklian government reversed earlier plans to reduce horse numbers in sensitive alpine regions, including Kosciuszko, and instead legislated to protect them.

Pressure to reconsider the heritage status of the horses will be revived when Parliament resumes after this weekend's election.

Reclaim Kosci, a group calling for a reduction of horse numbers, said on Wednesday it had secured the 10,000 signatures needed to force a debate on repealing the Wild Horse Heritage Act.

A degraded stream bank in Kosciuszko National Park, where University of Canberra researchers say brumbies are trampling the habitat of the stocky galaxias freshwater fish.Credit: University of Canberra

“These horses are [also] destroying the habitats of vulnerable native species such as the corroboree frog, the broad-toothed mouse and the Guthega skink," Linda Groom, a petition co-ordinator, said.

Labor's environment spokeswoman Penny Sharpe said a Daley government would repeal the act and boost resources to cut horse numbers and repair water catchment damage.

"The impact of horses on Kosciuszko is severe. The horses are pushing threatened native species to extinction," she said, adding that Labor "supports any urgent measures that look after native wildlife".

The Herald  sought comment from NSW Environment Minister Gabrielle Upton and Deputy Premier John Barilaro.

Cate Faehrmann, Greens MP and environment spokeswoman, said "surely there can be no better evidence of the damage that feral horses are doing to delicate alpine ecosystems than the need to install a horse-proof fence around the last remaining habitat of a threatened species".

“Instead of installing kilometres of fencing, which may too have an impact, the government needs to listen to the science and undertake a humane cull of feral horses in the national park to reduce their numbers," she said.

“In the last parliament the Greens introduced a bill to repeal the government’s laws protecting feral horses. I’m absolutely committed to raising this again when the new parliament sits.”