© Alexandra Morton
Atlantic salmon – Salmo salar
Atlantic salmon are the fish of choice for salmon farmers around the world. That’s because Atlantic salmon strains – such as the Mowi strain from Norway – have been bred to perform well in pens.
A total of 27-million Atlantic salmon eggs were introduced to British Columbia between 1985 and 2012. Since then, no reporting has been done to determine how many Atlantic salmon eggs are being shipped to Pacific waters.
Impacts of Farmed Atlantic Salmon in BC Waters
Raising Atlantic salmon among wild Pacific salmon introduces the enormous threat of bringing in diseases that wild salmon have no immunity to.
The crowded feedlot conditions of salmon farms allow bacteria and virus pathogens to breed unnaturally. They then flow into wild Pacific salmon habitat at higher levels than wild salmon have ever experienced.
This is high-risk management of wild salmon. Seeding their environment with pathogens means that whenever wild salmon become stressed, they are highly vulnerable to disease and death.
The virus piscine reovirus (PRV) is an example of a virus that infects farm salmon world-wide. Raincoast Research co-published a study on a Norwegian strain of PRV that is now found in BC farmed and some wild salmon (Kibenge et. al. 2013). No one knew the virus existed anywhere in the world until 2010 and so all salmon eggs introduced to the BC coast before that were not screened for this virus. This is a prime example of the hidden risk of farming an exotic species in pens that allow disease transfer between wild and farmed salmon.
Infectious Salmon Anemia virus (ISAV)
Infectious Salmon Anemia is a fish virus in the influenza family. When this virus first arrived in Chile, it was ignored until it mutated into a highly virulent strain that caused $2-billion in damages. Chile now takes ISAV very seriously.
Raincoast Research co-published a study on a Norwegian strain of ISAV in BC . It is an internationally reportable virus. Only fragments of the virus were detected in BC, but these matched a Norwegian strain called HPR5. ISAV is a major concern because it mutates easily – meaning it could follow the same course it did in Chile and mutate into a form that is virulent to Pacific salmon. Canada does not recognize the existence of ISAV in BC.