More than 300,000 lake trout were caught in Yellowstone Lake and killed this year, a record for fisheries managers trying to suppress the invasive trout species. The netting has been going on since 2000 as part of an effort to restore decimated populations of native cutthroat trout in Yellowstone national park’s largest lake.
The big lakers, also known as mackinaw, have outcompeted and eaten the native cutthroats since they were illegally introduced into Yellowstone Lake. The culling operation is finally reaching kill levels necessary to effectively suppress the ecologically damaging lake trout population, estimated at about 500,000 adult fish. Approximately 224,000 lakers were netted in 2011, but the total kill for the decade before was just 500,000.
One reason for the increase in netted lake trout is the use of tracking telemetry transmitters to find out where the fish were spawning and where they’re congregating. The kill was also successful this year because fishermen fished as long as they could, netting the 139-square-mile lake from just after the ice melted until last week, Hottle said. In 2011, Yellowstone contractors netted the lake for 17 weeks, but the season spanned just 10 weeks in 2010 and three weeks in 2009.
Cutthroat trout are considered a keystone species in the Yellowstone Lake ecosystem. They historically ran up 60 feeder streams by the thousands each spring to spawn. The spawn made them an easy catch for predators, and cut-throat were once an important food source for grizzly bears, bald eagles, ospreys and river otters.