Thursday, October 27, 2011

Virus Reported in Wild BC Salmon- Fact or Fiction?

A potentially lethal virus known as 'Infectious Salmon Amenia' (or 'ISA' for short) has been reported to be found in wild Pacific salmon on the northern coast of British Columbia, Canada.  Up until now, ISA has only been found in Atlantic salmon, which is a different species than any of the 5 species of fish that make up the group 'Pacific' salmon.  Therefore, if found to be accurate, this test would represent the first time this virus has been found in a new species of fish.

There are several factors to this scenario that demand pause and closer inspection before we run through the streets touting the end of salmon as we in BC know it.  First off, the test used to identify the virus is extremely sensitive and prone to results of false-positives.  Next, only 2 samples in 48 tested positive, which warrants further testing even in the best of circumstances.  However, the lab claims that the samples were all used up in the testing, and that repeating the testing is now not possible.  Any run-of-the-mill scientist will tell you that in order to preserve scientific accuracy, you never use all the sample for testing because the results of any test must be able to be reproduced- that is one of the fundamental principles of the Scientific Method!  And it is a requirement of all experiments in case EXACTLY this situation arises!

Next, this ISA virus has been linked to fish farms in other countries, yet not one case has been detected in the hundreds of salmon farms in BC.  The lab who found the virus is saying that they have identified it as the 'European strain': this implies that the virus came from Europe in farmed salmon eggs (which are rigorously tested by both the shipping and receiving nations), was incubated in a population of farmed salmon in BC (which are also tested under stringent Canadian federal regulations), was transferred to a completely new species, and then detected in that species.  Personally, that sounds like too many leaps of faith to accept before I join the growing masses heralding an "ISA-Salmon Doomsday".

So let's all sit back, take a breath, and let the facts unfold before we make any rash decisions...

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