Grass carp experiment at Aka Aka suspended

Press, 1 May 1984, Page 3

Grass carp experiment at Aka Aka suspended

PA Auckland An experiment using grass carp to control aquatic weed has been suspended for at least 10 months. The Waikato Valley Authority which administers the $1 million experiment voted yesterday to suspend the project because most of the fish had escaped. The Conservator of Wildlife at Rotorua, Mr Dave Stack, said a “guesstimate” suggested that only 50 of about 2500 fish brought in for the experiment were left in the experimental waterways at Aka Aka, near Pukekoke. The project had produced no constructive results on the pros and cons of using carp to control aquatic weeds in waterways, said

Mr Stack. The Wildlife Service opposed the introduction of the fish as they could threaten native wildlife in wetland areas. The Minister of Agriculture and Fisheries, Mr MacIntyre, announced two months ago that “some” carp had escaped from the experimentation area in the Waikato River. Since then, more fish have escaped and wildlife groups are worried they could threaten aquatic bird life in the Waikato. A Ministry of Agriculture and Fisheries biologist, Mr David Rowe, said from Rotorua yesterday that although the Ministry had 15,000 young grass carp in its breeding ponds in Rotorua, they were still too small to be released into the

drains. He said they needed to be about 30cm long at release. Mr Rowe said he hoped the experiment would be resumed about March next year, when the fish in Rotorua would be big enough to be released, but no firm decision had been made. He did not know what would be done with the fish' remaining in the drain system. The choices boiled down to killing them or leaving them there. Mr Stack said the Wildlife Service would ask that the fish be removed from the Aka Aka drainage area. It is believed that the Auckland Acclimatisation Society intends to oppose any recommencement of the experiment.