What could ISA mean for BC?

Infectious Salmon Anemia (ISA), a deadly salmon virus, crippled the Chilean salmon farming industry and outbreaks have now been reported in Scotland. We asked Dr. Neil Frazer, Professor at the Department of Geology and Geophysics at the University of Hawaii, what a virus like ISA could mean for BC.

What does this mean, scientifically, for a disease like ISA to be ‘endemic’?

It means that the disease is established and cannot be eradicated. The most one can hope for is to control it. Sea run trout can be a reservoir host for ISA.

A recurrence of ISA is being reported in Shetland, Scotland. What are the steps needed to contain this kind of highly infectious disease in each jurisdiction?

It is necessary to kill infected fish and then dispose of them away from the marine environment. Unfortunately, infection isn’t always immediately obvious, and farmers are understandably reluctant to kill fish until they are certain it is necessary.

Is there a threat of such an outbreak in BC? What would it mean for British Columbia’s wild salmon and coastal ecosystem if a similar outbreak were to happen here?

New Brunswick Canada is a good example. The ISA epidemic began there in 1996. By 1999, over 9.6 million farm salmon had been slaughtered for ISA control, and the provincial and federal governments had given salmon farmers $40 million for compensation and disease management. In 2006, the federal government gave the farmers another $10 million. ISA is now endemic there. Similar outbreaks have occurred in Norway, Scotland, Maine, and (most recently) Chile.

As far as we know, Pacific salmon are resistant to ISA. However, nature has an effectively inexhaustible supply of viral diseases, of which ISA is just one example. In 2001-2003 there was an epidemic of infectious haematopoietic necrosis (IHN virus) in BC’s Broughton Archipelago, indicating that stocking levels exceeded the threshold for viral epidemics. BC’s Sockeye, Chinook and Steelhead salmon are susceptible to IHN, and stocking levels have increased since the 2001-2003 epidemic.

Is there any way possible for net-pen salmon aquaculture to expand (or exist) in BC without increasing our risks to the threat of ISA? Would closed containment systems effectively reduce this threat of disease for wild fish?

Even without expansion, stocking levels have already made BC a “sitting duck” for viral epidemics.

I believe that the costs of disease control will eventually force salmon farmers out of the ocean and into closed containment facilities. Whether BC will have any wild salmon left when that happens, is the important question, and I am not optimistic about the answer. Fisheries and Oceans Canada (DFO) is obviously under extreme political pressure to promote aquaculture at the expense of wild fish, and it has a [total] budget of $1.5 billion dollars per year. With that amount of money, one could persuade the public that the moon is made of green cheese. Persuading the public that salmon farming is safe for wild salmon is easy by comparison.

The controversy on salmon farming reminds me of the controversies regarding the effects of lead, asbestos, tobacco and vinyl chloride on human health. In each case, governments were anxious to protect the industry, and since governments control the money for research, it took many decades for independent scientists to get the truth out. In the case of salmon farming, I am filled with admiration for scientists such as Alexandra Morton, John Volpe, Mark Lewis, and Marty Krkosek who have done such excellent work with shoestring budgets.