ISA doomsday prophecies prompt a strong feeling of déjà vu

Anti-salmon farming activists continue to preach a doomsday prophecy for wild salmon based on speculation that the Infectious Salmon Anemia (ISA) virus might be in B.C. waters.

But we’ve heard this sermon before. Its five points go like this:

“ISA is present in B.C. waters.”

“ISA could harm wild salmon.”

“It must have come from salmon farms because ISA is found on salmon farms (in Norway and Chile, but not B.C.).”

“Even if ISA occurs naturally in B.C. (as some sort of natural benign strain), farms could amplify it and make it deadly.”

“Therefore all salmon farms must be removed from B.C. waters.”

Does any of this sound familiar? If not, let’s try replacing “ISA” with “sea lice” to see if it jogs your memory:

“Sea lice are present in B.C. waters.”

“Sea lice could harm wild salmon.”

“Sea lice must have come from salmon farms because sea lice are found on salmon farms.”

“Even if sea lice occur naturally in B.C. farms could amplify them and make them deadly.”

“Therefore all salmon farms must be removed from B.C. waters.”

Anti-salmon farming activists are using the same illogical arguments to prophecy enviro-doom with ISA as they do with sea lice.

The scenario they suggest might be remotely possible, but is it remotely plausible?

No. Look at the evidence.

Have sea lice from salmon farms harmed wild salmon?

After more than a decade of extensive research, scientists are divided, with the only real consensus being “maybe, but we’re not seeing it,” a conclusion which was recently reiterated by scientists at the Cohen Commission (see project 5).

While farms may increase the number of sea lice in a small area, scientists see no meaningful connection between farm lice levels and actual productivity of wild salmon stocks.

Wild salmon returns fluctuate as they always have, and despite a century of fishing pressure (the only thing we know that definitively kills up to 80 per cent of returning salmon), salmon numbers seem to be actually on the rise since B.C. has experienced some cooler summers in recent years. For example, 2010 was the best Fraser sockeye return in 100 years.

Not even counting that record run, doomsday prophecies that sea lice would wipe out wild salmon have been proven wrong.

Therefore the logic behind those prophecies should be viewed with great skepticism when we see it applied to ISA.

IHN outbreaks have not affected wild salmon

From a science perspective, there’s already plenty of evidence to show that diseases from fish farms have no discernable effect on wild salmon runs.

Throughout the 1990s and in particularly in the early 2000s salmon farms were plagued with several outbreaks of Infectious Hematopoietic Necrosis (IHN). It was at its worst from 2001-2003, when 36 farms were affected. The outbreaks killed up to 94 per cent of the salmon at some farms, killing approximately 12 million farmed Atlantic salmon.

This was the worst disease outbreak salmon farmers in B.C. ever faced.

Salmon farmers made many big changes after the outbreaks, implementing new disease controls, siting and reporting protocols as well as testing procedures. Starting in 2003, the provincial government – which regulated aquaculture in B.C. at the time – and salmon farmers started keeping and publicly reporting a comprehensive fish health database, recording all instances of disease, diagnoses and treatments in sick fish as well as test results from fish sampled and tested at random by the government.

But what happened to the wild salmon?

Salmon returns to the Fraser River between 2001-2005, when IHN outbreaks would have conceivable had an effect, show no out-of-the-ordinary fluctuations.

Fraser sockeye returns (millions of fish) 2000-2010
Source: "B.C. salmon fishery's decade of decline"

Returns and commercial catches were generally lower than they had been in the past, although the stock health was not in decline. “Many spawning stocks of sockeye salmon in the upper Fraser River basin are not stationary but have been dramatically increasing in size over the last decades, following a massive disturbance of the stocks at the beginning of the 20th century.”

Salmon numbers fluctuate wildly, and have done so during the century or so humans have been recording their numbers. They seem to be more linked to ocean conditions and warming water temperatures than anything else.

Risk of virus ‘amplification’ low

And after the worst disease outbreak in the history of B.C. salmon farming, caused by a virus which has been proven to be able to infect and kill all species of wild Pacific salmon,  wild stocks are still healthy. Any ‘amplification’ of the presence of IHN virus by salmon farms did not have a discernable effect on wild salmon.

So if ISA is here, in some benign, natural form, why would the risk of ‘amplification’ by salmon farms be any greater than that for IHN, which we know is here, which we know kills wild salmon naturally?

And again we must reiterate that ISA has not been proven to be in B.C. Experts suspect that if there is an ISA virus here, it’s been here a long time, perhaps even as long as the salmon themselves have been here. B.C. salmon farms do not have the disease or the virus which causes the disease. Wild salmon are showing no signs of disease.

Given the evidence, and when considered with the IHN epidemic, the ISA doomsday prophecy should be considered for what it is – fearmongering based on nothing.

It reminds us of this classic Family Guy conversation between Peter and Brian, which is a perfect way to end this article.

Peter: I’ll handle it, Lois. I read a book about this sort of thing once.

Brian: Are you sure it was a book? Are you sure it wasn’t nothing?

Peter: …Oh yeah.


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