Fish fry, anyone? That could have been the question at Yellowstone National Park this year, where crews removed more than 300,000 non-native lake trout from Yellowstone Lake in a bid to protect smaller endemic cutthroat trout.
That haul brings to more than 1.1 million the number of lake trout removed from the lake since they were first discovered in 1994.
The Yellowstone cutthroat population, the lake’s only native trout, has been severely reduced by lake trout predation and other factors, including whirling disease and drought. However, after several years of sustained lake trout removal efforts, cutthroat trout population monitoring indicated an increase in abundance of young juveniles in 2012.
The cutthroat trout is an iconic species and treasure of park anglers and wildlife watchers. Spawning each year in the Yellowstone River and more than 60 of the lake’s shallow tributaries, the cutthroat has served a vital role in Yellowstone Lake’s ecosystem as an important food source for grizzly bears, birds of prey and other wildlife. The cutthroat decline resulted in several of these species having to use alternate food sources during certain times of the year.
The National Park Service increased the use of contracted netters to more thoroughly expand its reach in Yellowstone Lake again in 2012. From May to October the NPS and contract crews focused efforts in the West Thumb, Breeze Channel and Dot and Frank Island areas of the lake, where catches continue to be highest. Because the lake trout spawn within the lake itself during September and October, the suppression crews sought movement corridors and congregations of the large, mature lake trout during the final weeks of the season.
The NPS continues to work with Montana State University and U.S. Geological Survey researchers to set benchmarks for lake trout removal and to monitor the movements and spawning habits of lake trout. Radio-tagged lake trout continue to help fisheries scientists understand where lake trout are concentrated and where they are spawning so that removal efforts can be focused to maximize harvest.
The Yellowstone Lake program is supported by strong partnership with the Yellowstone Park Foundation, Trout Unlimited, Greater Yellowstone Coalition, and the National Parks Conservation Association.