Lead author of salmon disease review questions data reliability and policy logic behind B.C. farm closures.
Dr. Gary D. Marty, lead author of a recent peer-reviewed study challenging assumptions about pathogen risk from salmon farming, has raised further concerns about the scientific basis for British Columbia’s aquaculture phase-out policies.
In an email to SalmonBusiness, Dr. Marty criticised the interpretation of qPCR test data linking Tenacibaculum spp. to disease in wild salmon. “We are told that the bacteria Tenacibaculum spp. ‘are linked to negative impacts on wild salmon.’ However, when we adjust the data supporting this claim for potential false positives—using methods that are standard in accredited diagnostic laboratories—90–95% of the PCR test results for Tenacibaculum maritimum disappear because they are unreliable,” he said, referencing Table 5 of the new review.
Decades of data re-examined: Salmon farms pose minimal risk to wild stocks says study
He also pointed to long-term data on Fraser River sockeye returns, noting that salmon returns during the 30 years of farming in the Discovery Islands region were stronger than any 30-year period since 1900. “That’s the frustrating reality ~4,000 British Columbians are facing,” he said. “How many people would be willing to quit their job because somebody claimed their work was a threat to wild animals—even though those animals were more abundant than at any time in over a century?”
The study, published in Aquaculture, Fish and Fisheries, reviews more than two decades of pathogen risk literature and calls for more stringent validation of testing and modelling methods, particularly where findings influence regulatory decisions.
The authors of the paper are:
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Gary D. Marty and Esteban Soto, University of California, Davis
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Michael L. Kent, Oregon State University
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Thomas B. Waltzek, Washington State University
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Jayde A. Ferguson and Theodore R. Meyers, Alaska Department of Fish and Game
The Canadian government is currently implementing a plan to phase out open-net pen salmon farms in British Columbia’s coastal waters by 2029, citing precautionary concerns for wild salmon populations.