In Flathead Lake, near Kalispell, MT, lake trout have thrived. Lakers, introduced into Flathead in 1905, eliminated another introduced species, the kokanee salmon. Unfortunately, lake trout now threaten native species such as bull trout. According to Montana Trout Unlimited, bull trout spend their formative years in tributaries of the Flathead River before migrating to the lake. When they return, they fall prey to lake trout. By current estimates, there are only 2,500 to 3,500 bull trout in Flathead Lake.In Lake Tahoe, lake trout foraged on Lahontan cutthroat trout and contributed to their elimination from the lake in 1939. Lahontan trout, native to the Tahoe Basin, were classified as endangered in 1970. The classification was downgraded to threatened in 1975.
In Clear Creek, a tributary of Yellowstone Lake, spawning runs of cutthroat trout often numbered 50,000. The last count was 538. A population of 350,000 lake trout competes with and preys upon the cutts. Lake trout were first discovered in Yellowstone Lake in 1994 and efforts have been in place since that time to reduce the population including gillnetting, deep-netting, and increased soak-time for nets. The National Parks Service has also acquired a Great Lakes-style gillnetting boat making it possible to deploy and process more gillnets.
It will take a large effort to control and reduce the numbers of lake trout where they threaten native species.
But we can contribute. We can help control the population of non-native lake trout by harvesting them from waters where they threaten native fish. In many cases, liberal limits are in place, making lake trout an attractive target. Harvesting a limit of lake trout may only be a small part of the overall goal, but it is a contribution. It is a contribution that can help native populations of fish.
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