Kokanee numbers on Kootenay Lake a cause for concern

High number of predators likely cause of kokanee decline, government says

The kokanee

The kokanee

Last week the provincial government announced that, due to low numbers, the kokanee fishery on the upper west arm of Kootenay Lake would be catch and release only this year.

This spring, anglers landed fewer kokanee than usual in this part of the lake, which could be an indication that the overall numbers are down, says Greg Beithel, Public Affairs Officer, Ministry of Forests, Lands and Natural Resource Operations. “The  closure is a precaution aimed to support long-term kokanee conservation  efforts.”

The kokanee fishery in the main part of the lake already was closed and will remain so.

The Ministry reports that last fall, biologists counted 18,000 spawning kokanee in the main body of the lake and its tributaries, the lowest number since the annual count started in 1979. Scientists estimate that the fish laid 4.26 million eggs, down from a high of 265 million eggs in 1981.

“The ministry has worked with experts to review the Kootenay Lake kokanee collapse, and the consensus is that the primary cause was a very high abundance of Gerrard and bull trout, both predators of kokanee,” Beithel said.

Although no other kokanee populations in the Kootenay region have declined as they have in Kootenay Lake, Beithel says the Arrow Lakes Reservoir kokanee are at lower abundance for a number of different reasons, but largely due to several recent high-discharge water years in a row that have temporarily prevented the productivity of the kokanee food web.

As for another popular kokanee fishery — Koocanusa — there is no cause for concern, he says.

“The abundance and size of Koocanusa kokanee fluctuates naturally over time, but recent spawner surveys indicate a healthy population in the reservoir that can support a fishery as well as kokanee predators.”

Meanwhile, Beithel says the government, working with First Nations, the Freshwater Fisheries Society of BC and the BC Wildlife Federation, is moving forward on accelerating kokanee recovery in Kootenay Lake.

The Province has already taken a number of steps to address the kokanee decline, including:

Changing fishing regulations to decrease kokanee harvest and increase Gerrard trout harvest.

Initiating an aggressive kokanee re-building program. Last year, biologists planted 500,000 eggs in Kootenay Lake spawning channels and released an additional 95,000 fry in 2015. Biologists will release another 500,000 fry into the lake this spring.

Initiating a study of kokanee across the Province to identify stocks genetically suitable for future recovery efforts.

Continuing spawning channel operations, nutrient restoration and fish health testing.

Kokanee are landlocked sockeye salmon and are second only to rainbow trout as the most popular game fish in B.C.