Officials are looking into why more than one thousand Kokanee have washed up on the northern half of Okanagan Lake.
Samples from the current die-off have been sent to the Provincial Animal Health Centre, where they are being tested for disease.
Results are expected within the next two weeks.
At this point, the die-off is not severe enough to have a significant effect on Okanagan Lake's overall kokanee population.
Last year, biologists counted more than 180,000 spawning kokanee on the lake, which was considered equivalent to the average return over the past 10 years.