Read this story form CBC.ca reporting on the revelation from the Cohen Commission into disappearing sockeye that ISA virus or a similar virus has been in BC’s wild salmon since at least 1986, based on studies of sockeye livers from that time frame by Dr. Kristi Miller.

Department of Fisheries (DFO) biologists have told a federal inquiry
that fish samples, dating back more than two decades have tested
positive for a potentially lethal wild sockeye fish virus — but that
fact wasn’t publicly reported.

Dr. Kristi Miller, the head of molecular genetics for DFO in Nanaimo,
told the Cohen Commission on Thursday that frozen samples dating back
to 1986 have been tested, and show infectious salmon anemia (ISA) has
been in B.C. waters for at least 25 years.(Dec. 15, 2011)

Read more: http://www.cbc.ca/news/canada/british-columbia/story/2011/12/15/bc-salmon-virus-claims.html