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Giant whitebait release to prevent extinction

Media release

Published: 7 June 2017

What is speckled golden, swims and is endangered in New Zealand? It’s the rare and native giant kōkopu whitebait and 10,000 of them will be welcomed into Tāwharanui Regional Park this Saturday 10 June.

The experimental release of giant kōkopu, bred by commercial whitebait producer Manāki, is the largest reintroduction of whitebait in New Zealand to date. It aims to establish two self-sustaining giant kōkopu populations to support the national conservation of the vulnerable species.

Councillor Penny Hulse, Chair of Auckland Council’s Environment and Community Committee, says protecting our native fish is important because they maintain healthy aquatic ecosystems. 

“A diverse and thriving aquatic environment is important for supporting a rich natural array of plants and animals, many of which are found nowhere else in the world,” she says.

Giant kōkopu is one of only five whitebait species in Auckland and if they continue to decline at their current rate, they will be at risk of extinction in the wild.

Auckland Council Senior Ranger Open Sanctuaries Matt Maitland says fish surveys undertaken by the council found giant kōkopu were no longer present in Tāwharanui Regional Park or numerous other sites across the region.

“There has been a significant decline in the numbers of giant kōkopu over the past two decades. Nationally, this is likely to have been a result of habitat loss, water quality decline and land-use changes,” he says.

Work undertaken at Tāwharanui by parks staff, volunteers and community partner Tāwharanui Open Sanctuary Society (TOSSI), along with technical support and equipment from NIWA, has helped to restore the park’s waterways enabling the return of the whitebait.

Work to improve conditions in Tāwharanui’s streams and wetlands has included reducing water use for the farm and nursery and water losses through leaky infrastructure, restoring wetlands and creating a passage through the pest-proof fence to allow fish out but stops pests coming in. By offering a predator-free environment, giant kōkopu, which can reach up to 600mm in length and 2.7kg, will have a better chance of survival. 

Matthew Bloxham, the council’s senior regional advisor for freshwater, says “after an absence of 30 years, we’re excited at the prospect of returning giant kōkopu back to Tāwharanui. This will be a test case for further Auckland releases and will tell us more about how previously modified freshwater environments can be restored for native fish species.”

The whitebait once released into the sanctuary will be monitored to inform conservation efforts of giant kōkopu in the future. If the reintroduction is successful, the council plans to release a further 120 adult fish into the sanctuary.

The release coincides with the dawn launch of Matariki Festival 2017 taking place at Tāwharanui and has been made possible thanks to the council’s partnerships with TOSSI, Ngāti Manuhiri, NIWA and Manāki.

Aucklanders play an important role in the conservation of whitebait at Tāwharanui Regional Park and are advised to look but not touch or fish.