Novel idea helps rebuild South Island crayfish stocks

Novel idea helps rebuild South Island crayfish stocks

A forestry company has taken on the job of rebuilding stocks of freshwater crayfish in the South.

The unusual combination came about as a way of finding other uses for the forests' emergency fire ponds.

The freshwater crayfish known as koura are listed as a threatened species by the Department of Conservation. Now they're getting a boost, thanks to an unusual project by forestry company Ernslaw One.

It came up with the idea of farming koura in their fire ponds, as a way of bringing in extra income between harvests.

"I guess the fire ponds sit there and they're important in the case of a fire, but they're sort of a dead asset really," says Enslaw One aquaculture manager John Hollows. "And by farming koura in them, you can get some revenue."

The secluded ponds are hidden among the company's 11 forests in Otago and Southland.

A series of man-made ponds have also been dug to increase the breeding locations.

"That's the beauty of this project," says Mr Hollows. "We dig the hole, leave the ponds for a couple of years to age and develop, put some crayfish in and let them slowly breed away. We've got very low densities. We've got no feeding, nothing artificial in the ponds."

Around 400 ponds across forests in Otago and Southland have so far been stocked with koura, but it'll be a few years before they can be harvested.

The small team visit each spot just once or twice a year, harvesting up to 40 crayfish from an average pond.

"They are fairly aggressive," says operations supervisor Callum Kyle. "You get the odd nip from time to time, but it's not too bad. You've just got to be fast with your fingers I suppose."

They're currently supplying just one restaurant to test the commercial market, leaving smaller fish behind to breed and grow.

"The medium and large fish, they go to ponds that are currently empty to stock them as breeding fish," says Mr Kyle.

It'll be another four years before the operation is in full production mode.

But the company is confident of satisfying demand, and hopes to also release some crayfish back into the wild through stream restoration projects.

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