Unique little battler survives against the flow

By ANNE BESTON environment reporter

One of New Zealand's rarest native fish has been rediscovered in the Waitakere Ranges after scientists had presumed for decades it was extinct around Auckland.

The shortjaw kokopu (Galaxias postvectis) might not be the prettiest of fish with its undercut lower jaw and uniform brown colour.

But the Department of Conservation says it is a category A threatened species, which puts it on a par with endangered native birds such as kiwi and kakapo.

"It's a very, very significant find," said DoC technical officer Chris Roberts.

"We will be looking over the area carefully and seeing what we can do to protect it."

Three shortjaw kokopu were found in two streams in a remote area of the ranges last week by Massey PhD student Mike Joy, who has been studying New Zealand's native fish for six years.

"They're pretty underrated by most Kiwis," he said.

"People don't really know we even have native fish but these guys are found nowhere else in the world. They are unique to New Zealand."

The Waitakere discovery was part of a nationwide 200-site survey of native fish species Mr Joy is doing to complete his doctorate.

"They're so distinctive, we knew straight away we'd found them but it's been a surprise to everyone because there's been no record of them here in recent times."

Despite habitat loss, dams and the general degrading of their environment, the shortjaw kokopu appears to be surviving against the odds.

Mr Joy discovered robust populations in Taranaki when he was completing his masters degree.

The data he is collecting will be used to demonstrate how native fish can be used as indicators of water quality.

Of the other members of the Galaxiidae family, which is the largest family of freshwater fish with about 20 species, the giant kokopu is one of the rarest.

Quite a few of the more common banded kokopu had been found during his Auckland regional survey, Mr Joy said.

Shortjaw kokopu lurk under rocks and logs in heavily vegetated forest streams and hatch as juveniles in the headwaters before being carried out to sea where they live for about six months.

In late winter and early spring, they migrate back up rivers and streams to begin the cycle all over again.

They "stick and wriggle" their way over enormous natural obstacles during these journeys.

The number of dams being erected by lifestylers and developers made that journey ever more difficult and continued to threaten their survival, Mr Joy said.

"Lifestylers seem to be obsessed with making dams. I spend about half my time working with landowners about that."