Lake trout have worked their way into one of the only bodies of water in the nation where anglers are allowed to keep bull trout, and now biologists want to find out how big of a problem the intruders are.
For three weeks in September, biologists will sample fish in Swan Lake to assess and count its non-native lake trout population. Lake trout were first noted in the Swan drainage in 1998 and recent evidence indicates the population is growing rapidly.
Lake trout are predacious fish that “threaten the popular bull trout and kokanee fishery in the lake,” according to a Montana Fish, Wildlife and Parks press release.
The study is a collaborative effort between FWP, the U.S. Fish and Wildlife Service, U.S. Forest Service and Bonneville Power Administration. Its goal is to capture, mark and release alive as many lake trout as possible to achieve a population estimate. Biologists will use trap and gill nets to capture the fish – boaters are advised to watch for marked buoys to avoid trapping areas.