BC fish farm closures 'won't change wild salmon populations'
New paper challenges claims by anti-salmon farming scientists
A newly published academic paper has claimed that removing open net pen salmon farms in British Columbia – where the federal government is banning the practice from mid-2029 - will have no detectable effect on wild Pacific salmon population productivity.
The paper challenges claims made over the past two decades that there are significant impacts of pathogens transmitted from farmed salmon on wild Pacific salmon populations in British Columbia, western Canada.
The paper is in response to a recent review study (Krkošek et al. 2024) that claims pathogens are spread from farmed salmon and that they “likely affect wild salmon indirectly by mediating migration, competition, and predation”.
The review study, Pathogens from salmon aquaculture in relation to conservation of wild Pacific salmon in Canada, is lead authored by long-time salmon farming opponent and scientist Martin Krkošek, who is associated with the Pacific Coast Field Station run by long-time anti-salmon farming activist Alexandra Morton.
Alternative perspective
The assumptions and conclusions of the review are countered in a new paper, Pathogens From Salmon Aquaculture in Relation to Conservation of Wild Pacific Salmon in Canada: An Alternative Perspective, lead authored by Gary D. Marty, a research associate with the University of California Davis School of Veterinary Medicine who was employed as a diagnostic fish pathologist by the British Columbia Ministry of Agriculture and Food from 2004 to 2023 and now works as a senior fish pathology consultant. Around 70% of his work is for the salmon industry.
The paper has five other contributing authors who are employed by state government or state-supported universities in states that prohibit commercial marine net pen salmon aquaculture: Alaska, Washington State, Oregon, and California. The authors received no specific funding for the work.
'Evidence of impacts is weak'
“Several articles over the last two decades have provided data, analyses and interpretations that suggest there are significant impacts of pathogens transmitted from farmed salmon on wild Pacific salmon populations in British Columbia,” the authors say in the abstract of their paper.
“Because disease is a normal part of all animal populations, there is always a potential for pathogen transfer between animal populations that interact. However, the evidence is weak that pathogens transmitted from farmed salmon cause significant impacts on wild salmon populations.
“We provide additional data and alternative interpretations of the available evidence to show that (i) many studies overestimate the risk of pathogens transmitted from farmed salmon to wild Pacific salmon, (ii) these risks have not manifested as having significant impacts on wild Pacific salmon populations, and, therefore, (iii) the evidence better supports the conclusion that pathogens transmitted from farmed salmon are having no more than minimal impact on wild Pacific salmon populations.
“On the basis of this information, we hypothesise that removing open net pen salmon farms will have no detectable effect on wild Pacific salmon population productivity in relation to reference populations.”
