A pest fish dubbed the “possum of the waterways” has been almost eradicated from Travis Wetland.
Rudd are native to Europe, Russia and central Asia, and were illegally introduced into New Zealand in 1967. The pest fish, which compete with native fish species and damage habitat, have spread around lakes, ponds and rivers throughout the North Island as well as Canterbury and Nelson.
They were first detected in Travis Wetland Nature Heritage Park by Christchurch City Council Park Rangers in 2008.
Council and Department of Conservation staff immediately targeted the fish in April that year, with help from Travis Wetland Trust volunteers.
On the first night of fishing 400 rudd were caught. High numbers were also caught in 2009 and 2010 using fine mesh nets, known as gill nets.
However, after four consecutive seasons of zero catches, Council staff now believe that close to a decade of hard work to remove the fish from Travis Wetland’s central pond has paid off.
“We feel confident that we have reduced rudd's environmental impact to near zero," says Council Park Ranger John Skilton.
“It’s great to know that all that effort we’ve put in over the years has been worthwhile. It’s been a lot of hours in various weather conditions. If we hadn’t started fishing back in 2008 our waterways would have been overrun with them within two or three years.”
Just one fish can lay up to 50,000 eggs in spawning season. Although no rudd have been caught in the past four years, they are likely to be present in very low numbers and on-going monitoring is needed, he says.
“We have to keep going, we can’t stop, but instead of up to six months of fishing each year we will just do one session in February.”
Local ecology company Wildlands Consultants have independently verified Council monitoring and confirmed the zero catch.
It is hoped that bringing rudd under control will lead to an increase in the number and size of native fish species such as short-finned eel, inanga, black flounder, smelt, common bully and giant bully.
Members of the public should report any sightings of rudd to the Department of Conservation.