Rick Routledge: Disease-control policy for B.C. farmed salmon must include precautionary principle to protect wild fish

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      By Rick Routledge

      In his March 15 statement in the Georgia Straight, federal fisheries minister Jonathan Wilkinson seriously misrepresents the actions that he is required to take in order to comply with Justice Cecily Strickland’s February 5 Federal Court ruling.

      The judge ruled that the government’s policy regarding the management of PRV (Piscine orthoreovirus) was out of compliance with the precautionary principle and granted the minister four months in which to produce a revised PRV policy that would bring the government back into compliance with its legislated responsibilities.

      The precautionary principle was developed to provide timely, substantive protection against scientifically credible threats of serious, long-term, possibly irreversible damage. In my assessment, the minister’s March 15 statement falls fatally short of this level of commitment.

      Strickland had before her a clear record of the severity of the potential damage: the imminent extirpation of a rapidly expanding list of populations of wild Pacific salmon. All of these listed populations possess important local genetic adaptations—for some, these date back 10,000 years, to when residual ice dams blocked passage up the Fraser and Thompson canyons and Pacific salmon recolonized the Upper Fraser watershed via the Columbia drainage. The loss of such adaptations is essentially irreversible. Moreover, chinook salmon are the preferred prey for British Columbia’s endangered southern resident orca population. This dependency adds further urgency to the November 2018 listing of eight of 14 assessed populations of southern British Columbia chinook as at risk of imminent extinction, with a further four listed as threatened. The stakes are extraordinarily high; the need for substantive precautionary measures against credible risk factors is urgent.

      PRV is such a risk factor. There is, indeed, a growing national and international body of credible, scientific evidence demonstrating that PRV likely poses a risk to the health of Pacific salmon—and that Pacific salmon are even less capable of combating a PRV infection than are their Atlantic cousins. The evidence is not totally conclusive. Uncertainties remain, but the precautionary principle specifically dictates that lack of complete certainty cannot be used to justify inaction when there is a risk of serious, long-term damage.

      Definitive contrary evidence would allow the minister to dismiss such a body of otherwise credible evidence, but Strickland specifically noted the lack of definitive evidence that PRV does not pose a risk to wild Pacific salmon. Indeed, she further highlighted a remarkable weakness in the federal government’s evidence: heavy reliance on observed health impacts on farmed Atlantic salmon for inferring potential impacts on wild Pacific salmon. Such indirect evidence cannot possibly generate definitive conclusions.

      The following conclusions are uncontested: First, PRV is widespread and highly prevalent in Atlantic salmon farms in British Columbia. Second, PRV is highly contagious and can be passed from Atlantic salmon to at least two species of Pacific salmon (sockeye and chinook). Furthermore, it is a thoroughly accepted scientific conclusion that large, crowded host populations, like salmon in a large aquaculture facility, provide an ideal opportunity for a pathogen like PRV to proliferate. Thus, crowded fish farms are ideal breeding grounds for PRV to proliferate and spread to wild Pacific salmon to which they may pose an even greater health risk. Strickland was clearly correct in identifying that the minister’s PRV policy was at odds with the precautionary principle.

      In his March 15 statement, the minister promises “a more fulsome implementation” of the precautionary principle. Yet he states: “This means asking: if those with concerns about environmental impacts were eventually found to be correct, which concerns would be most damaging to the environment and what can we do to mitigate?” Implementation of the precautionary principle requires solid measures to protect wild Pacific salmon against threats of serious, potentially irreversible damage. The minister’s proposed mitigation measures, aimed at merely lessening the potential impact, fall fatally short of this profoundly stronger requirement.

      It is not even clear that the initiatives he outlined will lessen the impact. Shifting salmon farms from one area of the coast to another could potentially reduce the risk to some wild Pacific salmon populations but would almost surely exacerbate the risk for others. Feasibility studies for alternative technologies, though valuable, have no immediate impact on imminent extinction threats to invaluable wild-salmon populations.

      The minister has until June 4 to produce a revised PRV policy. Although Strickland, as a Federal Court justice, was constrained not to dictate a specific course of action for the minister to follow, it is inconceivable that a revised PRV policy could be in compliance with her ruling without (i) thorough, mandatory monitoring for the presence of this highly contagious virus in British Columbia salmon farms, and (ii) mandatory follow-up to eradicate PRV from salmon farms that test positive for PRV. Only then can the minister legitimately claim that his PRV policy truly represents an implementation of the precautionary principle, which he can then proceed to make “more fulsome”.

      Rick Routledge is a retired SFU professor with more than 15 years of experience researching the potential impacts of salmon aquaculture on wild Pacific salmon.