The Nov. 8 Mirror included a letter that I wrote. I estimated how long it would take the IHN virus produced by all the salmon in an infected farm to fill a single sockeye salmon egg. My calculations were wrong. The IHN virus is small, but not that small.
It would take about four days [not 11,000 years] for the infected farm to fill an egg with the IHN virus. I apologize for the error.
However, the important point remains. Sockeye salmon smolts in seawater are resistant to the IHN virus. Based on published research, I estimate that sockeye salmon smolts would be safer inside an IHNV-infected salmon pen (four per cent mortality over 37 days) than in the open ocean (50 per cent mortality in just 24 days).
Also, IHN outbreaks among farm salmon are rare. Since 2003, only one salmon farm has been diagnosed with IHN during smolt migration, and that farm was on the west side of Vancouver Island, far from most migrating Fraser River sockeye salmon.
Gary Marty, Fish Pathologist
BC Ministry of Agriculture
Editor’s note: A corrected version of the letter arrived but too late to include in Friday’s paper.