Scientists differ on threat from Atlantic salmon that escape into the wild

As an Atlanticsalmon advocacy group raises the alarm over escapes from New Brunswick salmon farms, two scientists are divided over whether farmed fish are a risk to their wild counterparts.

The Magaguadavic River has been the focus of the Atlantic Salmon Federation's data on fish that escape from the salmon-farming industry's open water nets in the Bay of Fundy.

A federation release earlier this fall said it had captured 46 escaped salmon in the Magaguadavic since Aug. 1, and argued they present a "high-level threat to wild salmon."

The group said farmed salmon aregenetically different from wild salmon because of "intensive inbreeding for commercial traits" and crossing with European species.

Brian Glebe, who has worked with Atlantic salmon for 45 years, including with the Department of Fisheries and Oceans andin the aquaculture industry, said escaped farmed salmon don't posea threat to the wild salmon population on the Magaguadavic, because the fish are genetically the same.

"TheMagaguadavic River is a unique river in that it never had a wild [salmon] population," said Brian Glebe.

Glebe said a fishway was constructed on the Magaguadavic in the 1920s, which allowed fish passage through the river from Passamaquoddy Bay, an inlet of the Bay of Fundy.

There were no salmon in the river, he said, so it was stocked with smolt, a juvenile salmon, from the St. John River system.

Thatsame population in the St. John River system was used to start the salmon aquaculture industry in the region, Glebe said.

"What they're calling wild fish are really the same genetic stock," Glebe said.

Another scientist says the opposite, however.

Scott Pavey, a professor and Canada Research Chair at the University of New Brunswick Saint John, is with the Canadian Rivers Institute andstudies the genetics of fish and fisheries.

He said the escaped farmed salmon are absolutely not the same fish as any stocked "wild" salmon in the Magaguadavic, which they're at risk of interbreeding with.

The farmed salmon"would be the same species, but that would be a domestic strain that's gone many, many rounds of artificial selection by humans compared to fish that have been in the wild and have been influenced by natural selection," Pavey said.

He said the aquaculture industry desires certain traits such as how the fish filets look as well as faster breeding and disease resistance.

"It's going to include a bunch of other traits that really don't have anything to do necessarily with a wild salmon being evolutionarilysuccessful, which would mean reproducing in nature," Pavey said.

He said that escaped farmed salmon are certainly a threat, and it's been shown that they can breed with wild salmon and produce offspring that are less genetically fit for survival and reproduction.

"That would be considered to be not a great thing that would be good to minimize," Pavey said.

But despite the threat of escapes, Paveysaid, aquaculture hasenvironmental benefits.

For example, he said, the salmon farming industry is far less damagingin terms of its carbon footprint and water use than the beef industry.

"It's a very low carbon food source, there's a lot of bang for your buck with fish aquaculture," Pavey said.

Salmon company 'puzzled' by claims

Cooke Aquaculture, the company the Atlantic Salmon Federation blames for the escaped salmon, wouldnot provide anyone for an interview, but spokesperson Joel Richardson emailed a statement.

The statement acknowledged there was damage to three ocean nets in August from seals but said the salmon inside were likely eaten by the seals and not able to escape.

Richardson disagreed with the claim that Cooke salmon are "genetically different."

"Cooke only uses native, non-genetically modified St. John River Atlantic salmon strain in our breeding program this is well-documented and highly regulated," Richardson said.

Cooke only uses salmon bred from the St. John River strain, he said, and it's the same strain that has been released in the Magaguadavic and other rivers in the province.

"We are puzzled by the ongoing disinformation being asserted by the Atlantic Salmon Federation that farmed salmon are a high-level threat to wild Atlantic salmon, or that they are cross-bred for commercial traits," Richardson said.

Why federation uses Magaduavic in research

Jonathan Carr, vice-president of research and environment with the salmon federation, acknowledged the Magaguadavic doesn't really have wild salmon, but he said the river is used as what's called an "index river" for scientists and government to measure how many fish could be escaping in a certain region.

"The real threat here is not [to] the Magaguadavic River in terms of wild stock," Carr said in an interview. "The wild stock is virtually gone.

"It's the surrounding rivers in the Bay of Fundy and the inner Bay of Fundy that are at high risk if we're finding this many escapes."

Carr said his organization has been monitoring the Magaguadavic for escaped salmon annually since 1992. He said the river was specifically chosen because it's in the "heart of the aquaculture industry" and because of the fish ladder, it's easy to collect and count fish that pass through.

Salmon farming begins with hatched fish that grow to a juvenile stage in freshwater tanks on land, then are transported to cages in the ocean to fully mature before being harvested.

Carr said there are body differences in the farmed salmon, as well as differently shaped scales.

"You can tell just by looking at them that these aren't wild fish," Carr said.

He said interbreeding between farmed and wild fish is dangerous, because less-fit genes are passed on. He echoed Pavey's concerns that the farmed salmon are fundamentally different from wild salmon.

"In as simple terms as possible, the fish reared in the industry have lost their wildness," Carr said.

He also added that wild salmon are at risk of picking up diseases and sea lice when they are near farm cages.

As for Cooke's claim that its farmed salmon are "non-genetically modified," Carr said this is"absolutely true," but selective breeding falls outside the definition of genetic modification, as "you can still genetically select traits without messing with organisms."

Carr said the federation is concerned there aren't efforts to catch escaped fish in nearby rivers. It has called on DFOto require farmed fish to be tagged so they can be identified more easily if they escape.

He also said the federation has offered samples of the collected fish to DFO and Cooke Aquaculture.

DFO's response to federation claims

The Department of Fisheries and Oceans would not provide anyone to speak about the issue but sent a statement.

Under the federal Fisheries Act, "DFO only licenses the stocking of farms with Atlantic salmon that have been assessed for disease, genetic or ecological risks, including consideration of mitigation measures, and that pose low risks to wild fish and their habitats," it said.

It said DFO licenses the federation to capture and record escaped farmed salmon, so the department is aware of he group's reports.

DFO recently convened a national meeting on risks posed to wild Atlantic salmon's numbers and diversity by "direct genetic interaction with fish that have escaped from East Coast Atlantic salmon aquaculture facilities." A reportis due later this year.

Call for 'balanced approach'

Reflecting on his own change of opinion on salmon farming, Scott Pavey said people should take a balanced approach to the topic.

He said he was first against the practice, citing instances of escaped fish on West Coast farms. But the industry is now better at preventing escapes, said Pavey, who comes back to his thought that farming salmon is much better environmentally than raising beef, pork or chicken.

"Becausethere's advocates that are pretty opinionated on either side and there's advantages and disadvantages to farming salmon, and you've got to look at it in a balanced way," Pavey said.

Public needs educating, scientist says

Brian Glebe said that he feels the federation doesn't appreciatethe advances the aquaculture industry has made to deter escaped fish. Fish cages now have lights shining on them 24 hours a day, which he said prevents them from maturing to a sexually active stage.

"If you don't have maturing fish when they escape, they don't breed with wild fish. Period," Glebe said.

It's also good business to eliminate salmon escapes, he suggested.

"No salmon farming company wants to lose fish, you're losing profit," Glebe said.

Ultimately, Glebe said, governments and public interest groups aren't always fully knowledgeable on the latestpractices inside the aquaculture industry and could be better educated.

He also wants to see all parties combine their efforts to focus on the real issue of declining natural populations of salmon.

"It's just not happening, there's so much adversarial effort going on," Glebe said.