Study by conservation group finds elevated pathogen levels near B.C. fish farms | Globalnews.ca
Conservationists have opened a new front in the ongoing battle over open net pen salmon farming in B.C.
The Pacific Salmon Foundation says its latest study has found that water near active open-net farms contains four times more pathogens harmful to wild salmon than water near inactive farms.
The foundation argues the research proves open-net farms contain and amplify pathogens that can affect wild salmon outside the nets.
The group looked at 11 sites in the Broughton Archipelago, seven with active fish farms and four that were decommissioned.
“We were sampling live and dead fish in the farms, but we were also collecting environmental DNA … the water inside and outside the farm in order to assess what is in the water,” foundation researcher Emiliano Di Cicco said.
“The problem is if a wild salmon gets infected and gets sick, it can either die directly from the disease or itself, or is more likely going to get weaker and not be able to feed properly and die or is not going to be able to evade predation.”
Di Cicco said the findings are particularly important for Chinook salmon, which spend their first year in the ocean close to shore in inlets and bays — the same terrain favoured by fish farms.
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“The first year in the ocean is very critical,” he said.
“So we expose the fish to a risk of being infected by a source that wouldn’t be in the water if we wouldn’t have salmon farms in the water when the fish migrate through.”
In an email, B.C. Salmon Farmers’ Association senior fish pathologist Dr. Gary Marty said the study did not provide “convincing evidence” that the risk of farm salmon disease to wild salmon was more than minimal.
“For as long as wild salmon have existed, migrating salmon have probably been naturally exposed to millions of infected salmon. Farms add no more than a slight variation to this pattern,” he said.
He added that the study couldn’t prove the infections came from farm fish or other fish attracted to the farms, and that it overestimated the consequence of some infectious agents to wild fish.
The Pacific Salmon Foundation says it supports the removal of all open water fish farms in B.C., something the federal government has ordered to happen by 2029.
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