Researchers at Nelson's Cawthron Institute are working to help Marlborough's salmon industry survive the challenges of climate change.
This week Voices visited the institute’s fin fish breeding lab, where large tubs contain salmon that are being monitored for growth and feeding habits. Sea water is pumped into these tubs from the ocean that's just a few metres outside the aquaculture park at Cawthron.
Jane Symonds is an expert in genetics and selective breeding, but working with fish wasn't exactly something she'd foreseen growing up in a landlocked part of the UK.
Chinook Salmon being monitored for thermo-tolerance and growth, Cawthron Institute, Nelson. Photo: Cawthron Institute
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“I grew up in industrial Northern England in a mining town in Yorkshire, and never really saw the sea.”
Once she came to Christchurch that all changed.
“I suddenly realised there's a whole beautiful world out there and having the sea on your doorstep was fantastic.”
This started her on her path to genetics and aquaculture, she says.
Jane's been at Cawthron for about five years now. She's part of a global team of experts, with nearly 300 scientists from 35 different countries.
New Zealand's salmon industry in Marlborough is based on farming a cold-water species of salmon that's susceptible to even half a degree or one degree change in water temperature. It faces huge challenges as a result of climate change and global warming.
“We've been selecting for these traits like growth and product quality. How can we now look at what we need to do to make our stocks resilient to climate change? And so that's an important question as part of the industry adaptation to what's coming or what's happening now because they're already being impacted,” says Jane.
To give a sense of the scale of that impact, last year was the first time New Zealand’s King Salmon had to close some of its farms because of higher ocean temperatures.
Tubs holding salmon at the Aquaculture Park of Cawthron, Nelson Photo: Cawthron Institute
That caused a net loss of $55.7 for the company in the 2022 financial year, with thousands of tons of fish having to be dumped in nearby Blenheim’s landfill.
The team at Cawthron have set up a temperature challenge working with New Zealand King Salmon and their breeding program to test salmon.
Early results are promising, Jane says.
“There is a genetic component to temperature tolerance. It's got a good heritability you can breed from it.”
The scientists test the salmon by warming water to a point that is sub-optimal for the salmon, she says.
“And then we look at how the salmon respond to that. And we then pick out the ones that do well at the higher temperature. And then we can relate that back to how they would do in the farms.”
New Zealand is the world's biggest supplier of King or Chinook salmon, accounting for about 85 percent of global supply.
Faced with the increasing impact of climate change, Jane thinks selectively breeding thermal tolerant fish could help avoid mass die offs like the industry saw last year.
But how does that actually work?
“A standard breeding program in aquaculture is where you take certain crosses between a male and female broodstock. And that produces a family like brothers and sisters. And they're all genetically related to some extent and you create maybe 100 of these families.
“And so, they've got different genetics, across the families. And then you basically can then evaluate those families and see how they do.
“So that can be growth, it can be the colour of the flesh, it can be their consumer quality, it can be thermal tolerance, it can be disease resistance.”
Large scale farming of fish like salmon is contributing to the very warming having a negative impact on the industry, but Jane believes there is still a place for carefully managed fish farming in New Zealand.
“If you think about the ocean that we have in New Zealand and what we can farm in the ocean, doing it sustainably and efficiently and taking environmental impact into consideration, we can help produce nutritious protein with lower emissions for the future and become less reliant on just sheep and beef and other products.”
Salmon contained in tubs at the fin fish breeding centre at Cawthron Institute, Nelson Photo: Cawthron Institute
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