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Rare giant kokopu, which are known as whitebait in their infancy, are being reintroduced into Akld waterways - Source: ONE News -
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The next time you chow down on a whitebait fritter you might
have scientists at NIWA to thank.
Whitebait numbers around the country are declining but now a
mission is underway to restore depleted stocks by following the
adult version of the Kiwi delicacy.
Scientists from the National Institute of Water and Atmospheric Research and the Mahurangi Technical Institute (MTI) have been catching and tagging farmed rare giant kokopu, which in their infancy make up part of the group known as whitebait, to reintroduce the species to Auckland waterways.
The aim is to repopulate Nukumea stream in Orewa, 40km north of Auckland, with giant kokopu.
The giant kokopu are black rather than white. In fact, they would make for an awful tasting and rather crunchy patty.
"Most people don't realise that whitebait are baby fish and they grow up into big fish," says Paul Decker, Mahurangi Technical Institute spokesman.
In whitebait years, the fish released on Wednesday are teenagers.
"If a stream has no parents the babies that are out in the wild from other streams won't come into the stream naturally," says Decker
As the giant kokopu swim off into the stream, NIWA is watching closely. It has implanted the fish with tiny transponder tags (PIT tags).
Each tag has a unique ID, so when the tagged fish are introduced to the stream NIWA will be able to identify each fish separately as they pass by the antennae positioned in the stream.
Paul Franklin of NIWA says it is the first controlled trial in New Zealand that tested whether native fish could be successfully stocked into a stream.
"By tagging the fish we are able to monitor how well they survive and where they choose to live.''
The last time a giant kokopu was seen in the stream was back in 2002.
But as the fish send out chemical signals, more giant kokopu should be attracted to the stream.
"The more adult fish there are, the more likely it is that juvenile fish will come into the stream," says Franklin.
The fish to be used for the trial have been hatched and reared in tanks at MTI from eggs originally collected from the Waitetuna River in the Waikato.
In the initial trial, about 30 adult giant kokopu will be released into the stream.
They will be monitored to see if the fish survive and breed and whether there is any impact on the fish and aquatic insects which already live in the stream.
If the first batch of big whitebait can bring in their younger, whiter and tastier counterparts, 500 lots of 1,000 juvenile giant kokopu will be released into the stream to combat the declining population.
