Testing in Nova Scotia confirms algae as substitute for fish oil in salmon farming

New studies out of Nova Scotia show oil made from marine algae grown in tanks can replace wild-caught fish as a key feedstock in salmon farming.

The results are a huge step forward in sustainability for an industry that relies on oil from wild-caught fish as the source of omega-3 fatty acids in salmon feed, said Prof. Stefanie Colombo, a Canada Research Chair in aquaculture nutrition at Dalhousie University's campus in Truro.

"There's huge potential to use this oil, not only in the Canadian aquaculture industry, but globally. And it's produced here in Atlantic Canada," said Colombo.

A Nova Scotia solution

The findings are confirmation for Mara Renewables Corp. of Dartmouth, N.S., which developed marine microbial algae oil — and its owner, John Risley, who recently questioned the sustainability of salmon farming in Atlantic Canada.

Mara Renewables takes micro algae from the Bay of Fundy, ferments and grows it in large tanks and then extracts the oils.

"We take the view feeding fish with fish is not only not sustainable, but in doing so, it is a huge barrier to growth of the aquaculture industry," Risley said in an email to CBC News.

"We hope to help aquaculture adopt a more sustainable model. Interestingly, these same oils help the poultry and pork sectors grow healthier products, so we are hoping to tap those markets as well."

How they tested

Colombo agrees feeding oil from wild fish to farmed fish doesn't make sense from an environmental sustainability standpoint.

She led tests of oil made from marine algae in the diets of farmed rainbow trout and Atlantic salmon, and published two separate studies on the results.

"We took all of the fish oil out and completely replaced it with the marine algae oil — and the fish, they grew the same. They grew just as well, if not better. Another important thing is that they stored the omega-3s right into their fillets in the muscle tissue, and that's important because as consumers, we need to get those omega-3s," she said.

Colombo, who is also an assistant professor in Dalhousie's department of animal science and aquaculture, said it's "a huge discovery" because other sources are needed to get omega-3s in the diets of fish. 

The research projects each cost $150,000 and were funded by the Ocean Frontier Institute based at Dalhousie and a food innovation grant from the Weston Foundation.

Mara Renewables poised to enter industry

Colombo said Mara Renewables can now use the scientific bona fides from the trials to enter the aquaculture feed manufacturing market.

It's a business opportunity for Risley, whose last public statements on salmon farming were an indictment of the way the industry operates in Atlantic Canada.

In an opinion piece this month in Atlantic Business magazine, the Clearwater Seafoods founder said no more fish farms with open-net pens should be approved in the region.

Escapes, he said, were threatening the extinction of wild populations.

Media coverage of the response included angry retorts from the industry and asides on the rivalry between two homegrown seafood barons.

A decade ago, Risley rejected an attempt by Glenn Cooke, founder of the Canadian salmon farming giant Cooke Aquaculture, to buy Clearwater.

Cooke Aquaculture initially declined comment for this story.

After publication, the company's vice-president of public affairs sent CBC News an email saying its fish feed is government approved. It added that 85 percent of the fish oil and fish meal used in its salmon feed is certified as sustainable by the Marine Stewardship Council or the Marin Trust, organizations that audit the sustainability of fisheries and marine ingredient factories.

Current practice not sustainable, says Risley

Risley's opinion piece largely dealt with the threat salmon farming poses to the survival of its wild component. It said the current practice of salmon farming is not sustainable.

"Wild salmon eat baby shrimp, capelin and most importantly algae, things which are rich in oils, particularly omega-3 oils. Farmed fish don't get that diet. Instead, they get a protein-based diet, mostly soy-based, to which is added fish meal and/or fish oils," he wrote.

He pointed to the white lines running through farmed salmon, saying they are lines of fat that "occur both as a function of the artificial diet and the difference in exercise for farmed fish versus its wild cousin."

Risley neglected to mention Mara Renewables has developed a product that will address a sustainability concern he raised.

Asked about the omission, Risley said his op-ed was not about self-promotion and Mara is not yet supplying the aquaculture sector.

"Anything anyone can do to help aquaculture become more sustainable is a good thing," he said. "I am not suggesting we shut down aquaculture, only that we examine its impact and find ways to ensure its impact is benign."

He said microalgal oil is still years from entering the aquaculture market.

'Wild fish stocks are finite'

Roberto Armenta, chief scientist and director of research and development with Mara Renewables, said he read Risley's piece in Atlantic Business.

"What I understood from it is that there is a need for such industry to produce its products in a truly sustainable way, seeking an economical benefit that is coupled with a minimal or zero negative effect on the environment," Armenta said in an email to CBC News.

"Wild fish stocks are finite, and making oil from algae addresses that problem by making fish oil without the fish."