DoC pulls catfish from Lake Rotopiko in pest control programme

From left, Mark Lammas, Jess Roeger and Nigel Binks on Lake Rotopiko this week, where they have been netting pest fish as DOC operational staff return to field work. Photo / Jeff Neems

More than 300 catfish were pulled from Lake Rotopiko in just two days when Department of Conservation staff returned to the field after Covid-19.

Since getting back out to work the rangers have been focusing on netting pest fish across the peat lakes throughout the Waikato.

Hamilton-based rangers Mark Lammas and Jess Roeger, and Biodiversity Senior Ranger Nigel Binks pulled out catfish, rudd and goldfish from the Ohaupo lake using set nets.

They have 33 nets spaced 20 metres apart across the whole lake.

"It's great to be back out in the field," says Lammas.

"Everyone has been pretty eager for a change of scenery and some pest fish work
definitely ticks that box," added Binks.

He says that the biomass of the catfish coupled with the sheer space they take up in the lake is of particular concern because of their ability to churn up sediment, harming aquatic plants and impacting on native species habitats.

Pest fish collected from the lakes are euthanised and turned into pet food or fertiliser.

Netting pest fish was originally supposed to happen in March but the Covid-19 lockdown meant this had to be postponed.

The work aims to regenerate and restore the peat lake environments. DOC is just one of several agencies involved in the restoration; other agencies include the National Wetland Trust, New Zealand Landcare Trust and Waikato Regional Council.

"The greatest satisfaction is actually pulling up a net and there's no fish in it at all," says Lammas.

Details of hauls will be closely recorded so data such as size the number of specimens caught can be analysed.