Kokanee salmon are a type of sockeye salmon that do not have an ocean phase in their lifecycle.
They were introduced to Montana in 1914 as an exotic species for fishing. Since then, they have become widespread in the western part of the state.
Boaters are being asked to clean and disinfect their boats and equipment when they travel between lakes, but that almost never works. Looks like Montana is stuck with IHN.
So far it hasn’t caused any problems, but the virus can be a problem in dense populations of salmon, such as in a hatchery or a salmon farm. Trout farmers in Idaho have struggled with it for years.
The virus is carried by sockeye up and down the west coast of North America, and its prevalence waxes and wanes with little discernible pattern.
What’s interesting about this article is that it makes reference to the APEX IHN vaccine and states that this vaccine is not approved for use in the USA.
Guess that means none of the salmon farms in Washington State are vaccinating against IHN?
All BC companies have been using the vaccine since 2012, when IHN was detected in three farms. The companies quickly culled all fish on those farms before the virus could spread, and strict biosecurity protocols were implemented until the winter.