NIWA scientists hope new breakthrough will solve 'critical problem' for New Zealand's salmon farmers

A new scientific breakthrough by researchers at NIWA may help the country's salmon farming industry solve a critical problem.

Currently most of the country's salmon farming takes place around Marlborough and Stewart Island, but the industry is hoping to expand, which means farming in more exposed locations. 

But unless new approaches are taken in the hatcheries that supply the juvenile fish to the farms, that growth will be difficult, says NIWA aquaculture scientist Dr Javed Khan.

Dr Khan has been working with University of Auckland PhD student Hsiao Heng (Tony) Pan to overcome the problem and says things are looking promising.

"Hatchery developments have lagged behind other advances in the New Zealand salmon industry which means there is an inability to produce the number and quality of juveniles needed to sustain future expansion," Dr Khan on Wednesday.

"This has been the impetus behind our recent research."

Trials over the past few months by Dr Khan and Pan at NIWA's Northland Marine Research Centre have shown that juvenile chinook salmon production can be ramped up in hatcheries if farming densities and husbandry conditions are optimised. 

"This is the first study of its kind and could solve a critical problem for New Zealand salmon farmers," NIWA said on Wednesday.

The most commonly farmed salmon around the world is Atlantic salmon, which can operate in hatchery densities of more than 80kg of fish per cubic metre of water. However New Zealand farms chinook salmon, which makes up less than 1 percent worldwide salmon production.

Pan said there was little existing research into how chinook salmon fare in high-density hatchery environments.

"The fish exceeded our expectations at higher densities, feeding and growing and not displaying any signs of stress," he said.

The next stage in the programme will see some fish transferred to a low-density, high-flow saltwater tank that "mimics typical conditions in the Marlborough Sounds" and others put into NIWA's recirculating aquaculture system, which replicates a modern salmon hatchery.

Dr Khan said many in the industry would be watching the trial closely. 

"What we are doing at Bream Bay is providing the science to support new economic opportunities for the country which is vitally important post-COVID."