Biologists have not yet pinpointed the cause of more than 1,000 kokanee to die off and wash up on the shores of Okanagan Lake.
Recent wind storms or a viral outbreak are listed as possible reasons of the ongoing die-off of Okanagan Lake kokanee which have been appearing on the shore since July 14.
According to the Ministry of Forests, Lands and Natural Resource Operations previous die-offs in Okanagan Lake and elsewhere have been associated with strong winds that can send warm surface water deeper into the lake. They said 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. 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.
The Ministry said the die-off is not severe enough, at this point, 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 the annual counts began in 1992.