Deadly salmon virus - one more reason to protect Bristol Bay's wild salmon fishery

You may have heard that the voters of Bristol Bay Alaska approved an initiative earlier this week to protect the Alaska wild salmon fishery from the massive Pebble Mine and other large-scale extraction that would damage salmon habitat.  You may not have heard that, on the same day, scientists announced the discovery of the presence of a deadly salmon virus in British Columbia that could threaten the entire Pacific Northwest fisheries.

The infectious salmon anemia virus (ISV) was first found in Norway in 1984 and quickly spread throughout Europe.  It largely only affects Atlantic salmon, but has been accidentally introduced via fish farming to areas such as Chile where the virus devastated the industry – causing millions of salmon deaths, driving the global price of salmon up and laying off more than a thousand Chilean workers.

What is most troubling about this week’s discovery is that the virus was detected in wild salmon from the Pacific rather than farmed Atlantic salmon.  Scientists are working to confirm the results and expand sampling to determine the source of the infection and the extent to which it may have already spread.  But if wild Pacific salmon are indeed susceptible to this disease then the entire Pacific Northwest salmon industry – from Oregon and Washington all the way up to Alaska – is at risk.

Viruses are persistent and highly adaptable and no country that has ever detected this particular salmon virus has been able to eliminate it.  Farmed fish are particularly susceptible to disease because they are confined to pens and limited in genetic diversity.  This gives wild salmon an advantage against the disease.  In fact, the best defense against a virus like this is robust populations of genetically diverse salmon in which inherent variability is more likely to demonstrate some natural resistance. 

Fortunately for the Pacific Northwest, Bristol Bay is home to the largest and most diverse wild salmon fishery in the world.  If this virus begins to wreak havoc on wild populations in British Columbia and surrounding areas, Bristol Bay salmon may be the salmon fishing industry’s best hope of surviving a major collapse.  That is, if Bristol Bay salmon are allowed to remain the tremendous resource they currently are.

The proposed construction of Pebble mine, a massive copper and gold mine, at the headwaters of Bristol Bay threatens to compromise the entire area’s salmon fishery.  Due to the sulfides in the ore, Pebble’s deposits are at high risk for acid rock drainage and metal leaching.  This pollution would likely be lethal to Bristol Bay’s famed salmon runs.  For example, research shows that even small amounts of copper (an increase of as little as two parts per billion over background levels) can be toxic enough to impair olfaction, which is critical to salmon migration, spawning and survival.  In a promising move, however, residents there passed an initiative earlier this week that would prevent large-scale mining that would destroy or degrade salmon habitat.

But the salmon are not safe yet.  The Pebble Partnership is challenging the initiative in court and is determined to move forward with their project despite strong community opposition and the many inevitable disastrous environmental effects.  The residents know that the value of the renewable resource of salmon that they and their ancestors have relied on for centuries far outweighs the fleeting pursuit of limited minerals.  Given the news of the virus, their vote turned out to be a prescient move.

Bristol Bay’s wild salmon fishery is too important to put at risk.  It’s time to say No to Pebble.

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Image: Bristol Bay Sockeye Salmon shared by toddraden via Flickr.