Lake Taupo trout under threat by catfish

Press, 1 February 1986, Page 13

Lake Taupo trout under threat by catfish

PA . / Auckland i The world-famous Lake ; Taupo trout fishery faces a new threat —' catfish. The wildlife conservator in Rotorua, Mr Dave Stack, says',the catfish have been introduced illegally into the lake. -T/ So far they have been found at Kuratau, Tokaanu Bay and Motuoapa. At least one of the catfish recovered .by-Wildlife Service rangers Had smelt and bully in its stomach. These are the main feed fish for the rainbow and brown trout jn the lake. Mr Stack said .the effect of;the catfish;bn the trout food chain remained to be seen. -'S'"•

“From the occurrence at three distinct it appears catfish have been introduced into-Lake Taupo

and may already have bred, I “We consider catfish are likely to become widespread' and abundant in the lake, with populations ’ concentrated in Waihi, Stump, Motuoapa, and Waipahihi bays.” ' Mr Stack said it was almost certain that the fish would inhabit ■ weedy, sheltered shoreline areas, which fortunately there were few of in the lake. The first catfish was discovered at Motuoapa on Christmas Eve. A resident found a strange fish floating in the marina and handed it to a wildlife ranger at Turangi. The second find was at Kuratau on January 7, when a Victoria University scientist set a net to .obtain samples of smelt and bully for research. Two live cat-

fish were among his haul.' Wildlife Service officers have now begun a netting programme. So far five live catfish have been captured, ranging in size from 10cm to 21cm. This suggests they are about a year old.

The fish mature at two years and, if in good condition, they can reproduce rapidly. Growth rates are reported to be much faster in New Zealand than in the United States. Fish ,33cm long have been recorded at four years of age. Catfish were introduced to New Zealand in 1878 from the United States. The first liberation was into St Johns Lake in Auckland.

They are common in the lower Waikato area where they spawn twice a year. Each fish releases thousands of eggs.