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Aquatic science biologist Howie Manchester pulls a bucket of salmon to collect samples from during a Department of Fisheries and Oceans fish health audit at the Okisollo fish farm near Campbell River, B.C., in 2018.JONATHAN HAYWARD/The Canadian Press

Accusations have recently been levelled against Fisheries and Oceans Canada, or DFO, and its use of science to regulate salmon farming.

Specifically, the House of Commons Standing Committee on Fisheries and Oceans heard from an organized group of scientists and anti-salmon farming activists who alleged that the DFO withheld certain studies. The group also criticized recent Canadian Science Advisory Secretariat reports concerning potential risk to wild salmon of pathogens from farmed salmon as being unreliable, because the reports did not support the activists’ claim that salmon farming poses significant harm to wild salmon.

As scientists who have contributed to many peer-reviewed analyses on salmon conservation and farming for the DFO, we’re compelled to respond to prevent propagation of any misinformation. Canadians can trust the scientific facts and advice presented by CSAS, the science evaluation body of the DFO.

Home-grown, ocean-farmed salmon is a valuable food resource for Canadians. It is an affordable, highly nutritious protein with year-round access. Such salmon – which is currently front and centre as the federal government is deciding whether to renew British Columbia salmon-farming licences – is affordable, in part, because it taps into renewable and free tidal power (driven by lunar cycles) for renewing oxygen and seawater.

Farmed-salmon aquaculture also has a low carbon footprint. This is partially because salmon are neutrally buoyant in water, needing less energy to survive, and the carbon dioxide they produce stays dissolved in seawater. The nutritious aspect of farmed salmon is, in part, a result of farmers looking after fish welfare and ensure the salmon are rich in omega-3 fatty acids.

Canadians need a reliable, sustainable and secure food system. All food production in Canada is regulated for safety, environmental impact and quality. This includes the rigorous regulatory oversight given to farmed salmon, which is also subject to passionate advocacy on both sides. In this context, responsible political decision making and a legal system to oversee fairness are crucial.

But providing reliable scientific advice to our elected leaders about environmental and food-science issues can be a challenge because they are not trained in these areas. The Cohen Commission, for example, examined in great detail the science concerning the risk that salmon aquaculture posed to wild Fraser River sockeye. Specific recommendations were made to DFO, some of which triggered three separate CSAS reports on the risk to the sockeye just from bacteria and virus transfer from salmon farms in B.C.

CSAS co-ordinates for DFO the routine production of peer-reviewed science advice, which can be given to our political leaders to support evidence-based decision making. A CSAS report typically takes over a year to assemble, after a group of world-leading experts begin their work, present and evaluate all relevant literature, especially peer-reviewed science. Their report is first vetted by an external peer-review, which may recommend improvements to the report.

All-in-all, the CSAS reports with which we participated did an excellent job of assembling and evaluating all the relevant scientific facts as a current state-of-affairs of the topics we studied.

First, the Fishing-Related Incidental Mortality for Pacific Salmon report of 2016 assigned salmon mortality percentages to those fish that encounter fishing gear (for example, hooks and nets) but are not actually caught, an alarmingly high number in some instances.

Second, the 2008 Closed Containment Salmon Aquaculture report of 2008 noted a major concern with the need for a high electrical usage in production, a problem that is still not fully resolved today.

Third, the 2019 report on Piscine orthoreovirus heard about experiments that deliberately injected the virus into sockeye salmon to infect them. The infected salmon’s ability to take up oxygen, to exercise and to withstand hypoxic water was not significantly harmed.

Consensus opinions were reported in the CSAS reports. While scientific facts are invariant, opinions on these facts can understandably differ. Dissenting voices are also noted in the process. So, should Canadians trust the CSAS process and their reports? Having collectively participated in many CSAS reports, our answer is: Yes, we should.

While the CSAS process is about as good as it gets when it comes to assembling available experts and facts, strengthening the process is always possible and its rigid format could be improved upon. In fact, the 2018 report from the Independent Expert Panel on Aquaculture Science chaired by Canada’s Chief Science Advisor recommended improvements to the flow of scientific information to communities and the involvement of international experts. The CSAS framework has made how expert opinion is obtained and incorporated into the reports more transparent.

Consequently, ministers charged with making decisions on the future of salmon aquaculture should trust the scientific facts that were presented in the recent CSAS reports concerning an industrial food sector that offers Canadian food security, and that is increasingly being adopted by First Nations along B.C.’s enormous coastline. The CSAS process does not selectively ignore some of the available science, as a form of bias – which may not be true for other expressed opinions being presented to the fisheries standing committee.

Tony Farrell is a professor and Canada Research Chair for fish physiology, culture and conservation at the University of British Columbia.

Tillmann J. Benfey is a professor of biology and director of animal care at the University of New Brunswick.

Mark Fast is a professor and chair of the department of pathology and microbiology at the Atlantic Veterinary College.

Kurt Gamperl is a professor and associate director of the Department of Ocean Sciences at the Memorial University of Newfoundland.

Ian Gardner is professor emeritus at the University of Prince Edward Island and the University of California, Davis.

Jim Powell is managing director of Fidelis Aquaculture Management Ltd.

Crawford Revie is a professor of epidemiology at the University of Prince Edward Island and chair of data analytics.

Spencer Russell is an associate professor at the Department of Fisheries and Aquaculture at Vancouver Island University.

Ahmed Siah is managing director at the BC Centre for Aquatic Health Sciences.

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