The future survival of the Fraser River’s wild salmon is of outstanding importance to British Columbia. This billion-dollar resource is priceless in terms of the ecosystem as a whole; salmon are more than just fish, they are a provincial icon. Fraser sockeye salmon had a great spawning run in 2010, with 34 million returning adults, three times as many as predicted. Yet this was a huge change from the preceding years, which saw an unprecedented and unexplained slump from an average of eight million spawners prior to 1992 to a mere 1.7 million in 2009.
What is behind this extraordinary volatility and unpredictability? Has the problem that caused the decline been solved, or will it return? Justice Bruce Cohen’s Commission of Inquiry into the Decline of Sockeye Salmon in the Fraser River was instructed to find answers; the most recent round of evidentiary hearings, covering aquaculture, has just been completed.
Attributing causal effects is complicated by the sockeye’s life cycle being distributed over marine, estuarine, and river habitats, with a four-year abundance cycle. The commission is considering 26 major reports and hundreds of submissions on factors implicated in the sockeye’s decline, including over-fishing, disease, environmental changes and pollution, the impact of fish farms located on migration routes, climate change, and the Department of Fisheries and Oceans’ policies and management.
Any conclusion on the cause of the sockeye decline must take into account their sudden rebound and it is feasible that more than one factor is involved. A disease outbreak is a highly plausible, and complex, candidate. Pathogens may not cause fatalities until an additional stress, perhaps from environmental factors, such as high water temperature or pollution, tips the balance. Alternatively, rapid, virulent disease outbreaks can occur among populations lacking immunity, despite an apparently healthy environment. Fungal diseases, such as chytridiomycosis in frogs and white nose syndrome in bats, have spread around the world, causing extirpations and population collapse in newly exposed populations. Honey bee colonies worldwide have been struck by Colony Collapse Disorder, associated with bee paralysis viruses. In this case, environmental factors, such as an introduced Asian mite called Varroa destructor, pesticides, and stress seem to contribute to hive collapse.
If a pathogen outbreak is a cause, any role that salmon aquaculture plays in spreading the disease must be examined, given that open-net-cage facilities lie on migration paths of Fraser River sockeye. Aquaculture includes Atlantic salmon, as well as chinook and some other species, and was begun by Norwegian investment in the early 1980s. From 1989 to ’92, a drop in the price of salmon meant consolidation into larger facilities, with just a few owners. This was the same time that wild fish productivity began to plummet.
Pathogens with the most serious impact on sockeye include viruses, bacteria, and parasites. Infectious hematopoietic necrosis (IHN) virus outbreaks caused significant mortalities in Atlantic salmon farms near Campbell River from 1992 to 2001, and have also been found in juvenile sockeye and chum in freshwater. The salmon leukemia virus is linked with plasmacytoid leukemia (infectious salmon anemia), which is common among seawater pen-reared chinook in Chile, Scotland, and Canada, and is also found in wild salmon. Outbreaks of this disease have caused death rates approaching 100 percent, and require total eradication of a farm’s stock to prevent spread.
For long-term sustainability of all fish, regulatory government departments, and the aquaculture industry should be as open as possible about such problems. This has not been the case. The B.C. provincial government chose to block the public release of fish health audit records for months, until finally submitting to the Cohen commission. One of these records shows that despite a chinook salmon farm having 96 percent of sampled fish with symptoms of anemia, no “fish health incident” was reported or investigated. Is such a dereliction of duty caused by unsuitably close ties between government staff and the aquaculture companies?
The federal government has also attempted to control information with implications for the harmful potential of aquaculture. In 2011, Kristina Miller, a scientist with Fisheries and Oceans Canada, and 14 co-authors published a study in the journal Science identifying a genomic signature (an expression of certain genes) in wild B.C. salmon that was predictive of whether the fish would survive migration and spawn successfully. The authors found associations between this genomic signature and numerous biological processes, especially those involved in response to viral infections and associated with lymphoblastic leukemia-lymphoma. The data led Miller et al. to hypothesize that “elevated mortality is in response to a virus infecting fish before river entry and that persists to the spawning areas”. Science is a highly prestigious journal and all published papers are subject to stringent peer review. The findings were relevant and of interest to many people. Amazingly, the Canadian Privy Council Office prevented Miller from speaking in public or to the media about her work. She has since stated that the virus could be a major factor in sockeye decline, but more research is needed. Whether there will be funding for that work is another matter, as DFO is now questioning whether her lab will be able to receive external sources of money.
The possibility of a viral outbreak having an effect on wild salmon populations is highly plausible. I believe that the vast majority of British Columbians would like honesty and openness in regards to this issue. Unfortunately, the close links between government and the aquaculture industry create a lack of credibility; sweeping statements by representatives that deny any problems with fish farms or any impact on wild stocks merely increase suspicion of a cover-up. Scientists must be free to do the necessary research, regardless of the political and financial implications of their findings. We need facts and clarity, not obfuscation, deception, or hidden agendas. Our wild salmon are worth it.
Anne Murray is an independent writer and naturalist, and the author of two books on the Fraser River delta—A Nature Guide to Boundary Bay and Tracing Our Past: A Heritage Guide to Boundary Bay—both available at bookstores or from www.natureguidesbc.com.