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Stocking of lake will build up catch

by John Keery
Courier Staff
Friday, September 26, 1986

The Fish and Wildlife branch still does not know why thousands of Kokanee Salmon died in Okanagan Lake in June, nor do they have an accurate count of how many fish actually died.

“We tested them for disease, viruses and so on but couldn’t come to a definite conclusion,” fisheries technician Steve Matthews said Thursday.

He estimates that anywhere from 10,000 to 100,000 Kokanee may have been lost throughout the summer which “could have an effect on the number of fish in the spawning run.”

However, fisheries biologist Dave Smith says the dieoffs seem to be a kind of nature population control mechanism and usually do not result in a decline in fish catches.

The best fisheries can do to deal with the problem is to continue stocking Okanagan Lake with fingerlings, produced at the Skaha Hatchery and try to build up the population, say both Smith and Matthews.

Mission Creek, as the largest tributary to Okanagan Lake and the most important spawning stream for Kokanee Salmon and Rainbow Trout in the Okanagan River system, is also the chief source of eggs for the the Skaha Hatchery at Okanagan Falls.

Each fall when the four-year-old Kokanee swim up the creek to spawn fisheries officers are there to trap some of the fish, and collect up to 1.5 million eggs to be used to raise fish to restock Skaha and Okanagan lakes. During the egg collection process, a careful estimation of the number of spawning fish is also made.

Figures are not yet in for 1986, but to 1985 about 150,000 Kokanee went up Mission Creek. That same year 33,000 used Powers Creek and 12,000 used Peachland Creek.

“This gives you some indication of the importance of Mission Creek,” Matthews said.

Rainbow trout also use Mission Creek when they spawn in the spring. Trout eggs gathered there are then used by the hatchery to produce 20,000 to 40,000 rainbow trout fingerlings which are released into Okanagan Lake each year.

The reason fewer rainbow are put in than Kokanee is that rainbow eat Kokanee.

“If we put in too many rainbow we can’t enhance the Kokanees. So we decided to hold off on stocking the Rainbows,” Matthews explained.

One side effect of a lower fish population can be larger fish, Matthews says. While fisheries officers were collecting Kokanee eggs in Mission Creek the week of Sept. 15 to 20, they noticed that the fish were exceptionally large. “The average Kokanee is about 11 inches. This year we’ve seen fish up to 22 inches. That would be about seven to eight pounds.”