Threatened native whitebait species discovered in Hawke’s Bay

Hawke's Bay Regional Council have confirmed that the rare shortjaw kōkopu, a species of whitebait, lives in northern Hawke's Bay thanks to an innovative technique. Photo / DoC

An innovative technique using DNA traces has uncovered the presence of a threatened native fish in Hawke’s Bay.

Shortjaw kōkopu are one of the five whitebait or inanga species, and their national conservation status is Nationally Vulnerable, according to the Department of Conservation (DoC), which means they are at high risk of extinction in the medium term.

A brand-new population of the rare fish was recently discovered by Hawke’s Bay Regional Council in Northern Hawke’s Bay.

Dan Fake, a council senior scientist, said this was the first time the native fish has been found in Hawke’s Bay.

“Shortjaw kōkopu are classified as threatened. This rare fish is also taonga, so we are thrilled to discover a potential population in our region,” Fake said.

Council detected the species’ presence using eDNA while water testing in the Kopuawhara catchment north of Māhia Peninsula.

The technique can identify DNA that has shed or been excreted from organisms into the natural environment.

“There’s more research to be done, as eDNA only tells us that they are present, not how many are in the catchment. The next step for us is to find out more about their population size and pinpoint where they’re residing,” Fake said.

Shortjaw kōkopu are rare on North Island’s East Coast, with only a small number recently discovered in Tairawhiti Gisborne.

Andrew Horrell, a council freshwater ecology technician, said it was likely both populations were linked considering their proximity.

“We know the Kopuawhara catchment drains into the sea north of Māhia Peninsula. Given the presence of this species in Tairawhiti, it’s anticipated the Hawke’s Bay population has originated from the same larval supply,” Horrell said.

The council will be working with mana whenua, DoC and landowners to develop a targeted survey and learn more about the shortjaw kōkopu population in Hawke’s Bay.

Threats to shortjaw kōkopu include loss of native forest habitat, more intensive land use, poor water quality, whitebait fishing, barriers preventing fish migrating, climate change and predation from introduced fish.

The New Zealand whitebaiting season begins on September 1 and runs until October 30.