SEATTLE — A deadly virus that caused salmon farmers in British Columbia to kill 560,000 fish has shown up for the first time in a Washington state fish farm.
The Orchard Rocks salmon farm on Puget Sound’s Bainbridge Island is killing off its stock after fish were diagnosed with the IHN virus.
Infectious Hematopoietic Necrosis virus occurs naturally in wild salmon and does not cause massive die-offs, but farmed Atlantic salmon are very vulnerable to the disease.
The infected fish are safe for people to eat, so the farm is butchering and selling the ones that are market-size.
Scientists think that when fish are kept in confined conditions, viruses can mutate and become more virulent.
That has wild fish advocates raising concerns about possible risks to the juvenile salmon that are migrating out of Washington rivers right now.
There are over 120 pens of farmed salmon in Washington.
Correction: May 24, 2012: This story originally mischaracterized the historical significance of the recent discovery of a virus among farmed salmon in Puget Sound. It is the first time the virus has been detected in a fish farm in Washington state, but not the first time it has appeared in Washington waters.