Auckland Council senior freshwater adviser Matthew Bloxham with fish pulled from the lake. Photo / Auckland Council Facebook
Auckland Council senior freshwater adviser Matthew Bloxham with fish pulled from the lake. Photo / Auckland Council Facebook
Pet owners are being warned about responsibly disposing of unwanted fish after half a tonne of exotic fish were hauled out of Western Springs lake.
The fish were caught last week using New Zealand’s only electric fishing boat. The good news was no native fish were harmed from the electricshocks.
“It temporarily stuns the fish, which means we can recover them,” Nicolas Ling told RNZ, an Associate Professor in Biodiversity and Ecology at the University of Waikato’s School of Science.
“The native species, we can recover those, and we can put them back in the lake unharmed, and the pest species, we can humanely euthanise them.”
A spokesperson for Auckland Council said 372 fish were caught, making 516kg of fish. The catch consisted of koi carp, goldfish and catfish.
The biggest carp weighed 14.5kg and was 81cm long.
The far left fish is a koi. The two orange fish are pet goldfish. The two on the right are two goldfish bred in the lake. Photo / Auckland Council Facebook
Part of the carp family, common goldfish can grow up to 45cm long in the right conditions, however, each species will vary in size, according to the SPCA.
Carp are extremely long-lived, able to live decades, with the record being 49 years.
“Releasing exotic fish into waterways harms natural ecosystems by forcing native species to compete for habitat,” the council spokesperson said.
“By feeding on native plants and disturbing pond sediments, they can release nutrients, which stimulate algal activity and turn water a soupy pea green colour.”
The fish were caught using the University of Waikato’s electric fishing boat which applies a current to the water around and beneath the boat.
“This causes muscles to contract involuntarily bringing them to the surface, where they can be scooped up with long-handled nets.”
The exotic fish were then euthanised and sent to a plant where they turned into bio-ethanol, which can be burnt.
The council said it is important to dispose of unwanted pets responsibly for the good of the environment and of the fish.
“Pets are used to being fed daily by their owners and kept in safe enclosures; they are ill-equipped to survive in the wild. It’s a bit like sending your pet into a survival reality show with a multitude of dangers from hungry predators to harsh environmental conditions.
A mature goldfish pulled from Western Springs late. Photo / Auckland Council Facebook
“Pets released into waterways are likely to suffer from malnutrition, injuries, stress and disease. Those exotic fish that survive their initial introduction into the wild can breed quickly, making pet fish difficult to get rid of once they are established.”
If owners can no longer care for their fish, council suggested finding a new owner, returning it to the pet store or finding a fish rehoming group such as Auckland Fish Rescue or North Shore Turtle Rescue.
