Recent wind storms or a viral outbreak are potential causes of the ongoing die-off of Okanagan Lake kokanee. More than 1,000 kokanee have washed up on the shores of the lake since July 14.
“While biologists have yet to pinpoint what is causing the kokanee deaths, previous die-offs in Okanagan Lake and elsewhere have been associated with strong winds that can send warm surface water into deeper into the lake,” said the Ministry of Forest, Lands and Natural resources in a press release.
“Such sudden changes in water temperature can be deadly to kokanee.”
Die-offs in other lakes have been linked to the infectious hematopoietic necrosis virus – IHNV. Staff at the Freshwater Fisheries Society of B.C.’s fish health lab in Duncan, are analyzing kokanee tissue samples to find out if disease was a factor in the most recent deaths.
At this point, the die-off is not severe enough to have a significant impact on Okanagan Lake’s overall kokanee population. Last year, biologists counted more than 336,500 spawning kokanee on the lake, the most since annual counts began in 1992.
Kokanee are landlocked sockeye salmon and are second only to rainbow trout as the most popular game fish in B.C.