When it comes to killing Catfish, William Anaru of the Te Arawa Lakes Trust is one of the best. So good, his Catfish Killas programme took home the top prize at the New Zealand Biosecurity Awards.

"The initiative started between the Bay of Plenty Regional Council and the Te Arawa Lakes Trust and we work real closely with the biosecurity team within the council," he said.

"From there, I go out and I've found a whole bunch of volunteers."

The project aims to stop the spread of catfish in Rotorua's lakes with the ambitious goal of eventually eliminating the pest altogether. This year 16 schools and one early childhood centre have offered their help as have some local at-risk youths.


"At the start, they're a bit stand-offish, but they change their ways once they actually see catfish and how bad they can actually be," Anaru said.

Working alongside the volunteers is the biosecurity division of the regional council, which brings the latest in scientific advancements to the fight.

"In the future, we'll be looking at using environmental DNA," biosecurity officer Lucas MacDonald said.

"It's a water monitoring technique that picks up any species in the water and we'll be rolling that out across the wider Rotorua lakes.

"We've also asked science providers to look into what can be done in the form of biocontrol. They'll be coming back to us with a feasibility report early next year.

"We'll also be using some of the tools we've developed in the past, like the pheromone bait which is good for attracting catfish into the nets, and we'll be refining that further."

Catfish are not well-researched internationally, so what's being learned in Rotorua is making a valuable contribution to global knowledge of the species.

"There's not much known about them globally," MacDonald said. "In some countries they're obviously a native so there's not much done on them. And in the past, there hasn't been much research done on catfish.


"So with this incursion that happened in 2016, it's allowed us to really create quite a lot of knowledge and also summarise everything that's going on across the world with this species."

And they're making some very real progress.

"In the first few years, we've seen a steep increase in catfish and from our last season we've actually seen an 18 per cent decrease and this was with quite a lot more netting.

"We'll be looking to see what the numbers are coming in from this summer and we'll be looking to see if that's going to keep decreasing.

"At the moment with the tools we have, we're pretty confident we can suppress them to within Rotoiti and Rotorua, but we obviously need the public's help to stop the spread into further lakes."

The public is asked to check all gear going into and out of every waterway in the region.

"If you're using a boat and trailer, make sure you're not carting any weed or any small juvenile pest fish between lakes," MacDonald said.

As for where the initiative is heading, the Catfish Killas has a secret weapon up its sleeve.

"Next year we're going to have a couple of aged care groups involved in our programme and another five schools coming on," Anaru said.

"We're letting everyone get involved."

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