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Low kokanee numbers prompt bull trout quota increase

The seasonal no-fishing regulation for the north end of the main body of Kootenay Lake has been lifted. — Photo courtesy Friends of Kootenay Lake

The north end of Kootenay Lake and the lower Duncan River are now open to regulated bull trout harvest to support long-term kokanee conservation efforts.

The daily quota for bull trout has increased from zero to two on the Duncan River, downstream of where it converges with the Lardeau River, from Oct. 5 to March 31, 2019. The seasonal no-fishing regulation for the north end of the main body of Kootenay Lake has been lifted.

Increasing bull trout harvest is consistent with recommendations in the Kootenay Lake Action Plan to recover Kootenay Lake kokanee stocks. Bull trout rely on kokanee as a food source, so reducing bull trout now to stabilize or increase kokanee numbers will ultimately mean a healthier bull trout population. Population and diet trends indicate bull trout populations are contributing to kokanee mortality rates that are much higher than normal.

Historically, the number of spawning kokanee in Kootenay Lake ranged from 250,000 to nearly 2.2 million. This number declined to 18,000 in 2017 due to historically high kokanee predator abundance (bull trout and Gerrard rainbow trout).

There is concern that recent low spawner abundance and juvenile supply of Gerrard rainbow trout has led to population reductions of Gerrard rainbow trout in Kootenay Lake. Bull trout, on the other hand, have spawning populations that increased by more than 100% between 2015 and 2017.

Reducing bull trout populations in the short term, in addition to continued stocking of kokanee eggs, is a short-term strategy to improve kokanee recovery. The ministry began stocking kokanee eggs in 2015. Since then, 16 million eggs have been stocked and another five million to seven million eggs will be stocked this fall.

Ministry biologists assess populations of kokanee, bull trout and Gerrard rainbow trout annually to monitor recovery status.

The 2016 Kootenay Lake Action Plan was developed by an advisory team with representatives from the ministry, Freshwater Fisheries Society of B.C., the BC Wildlife Federation and First Nations.