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Electrofishing Boat Zaps Fish Pests

Media Release
14 August 2003


Electrofishing Boat Zaps Fish Pests

It looks like something from a science fiction movie. But Waikato University's electrofishing boat Te Waka Hiko Hï Ika is very much the real thing when it comes to catching fish pests in Waikato waterways. This is New Zealand's first successful electrofishing boat.

The boat has spectacular electronic prongs in front that dangle under the water. It was been developed by senior lecturer Brendan Hicks and technical manager Dudley Bell from the University's Department of Biological Sciences.

The prongs are anodes powered by a 1000-volt generator-powered pulsator purchased from Smith-Root in the United States. A five kilowatt output custom-wound generator powers the pulsator. Poles and droppers create the electronic fishing field around the prongs, and the boat itself acts as the cathode. Fish attracted by the electronic field can be scooped up from the boat.

The electrofishing boat has many advantages over conventional fish capture techniques such as netting. The electrical field attracts bottom dwellers such as catfish and eels as well as mid-water fish such as rudd, koi carp, tench, grey mullet and perch compared to netting usually captures fish from only one location. Netting usually catches only a narrow range of fish sizes, but the electrofishing boat catches fish of all sizes.

The main targets of the boat are pest fish such as koi carp, rudd and catfish. The boat will be used to learn about the density of pest fish populations and their biology, as well as to study the best ways to control them, says Brendan Hicks.

Captured pest fish can be killed while native fish can be returned to the water unharmed.

We started using the boat recently in the Waikato region and we intend to keep using it here and in the Bay of Plenty in pursuit of pest fish, says Brendan.

The 4.5 metre boat was purpose-built in Rotorua by Orca Engineering and Marine Ltd.

ENDS

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