Non-Native Trout Population Declining In Yellowstone Lake

Nov 26, 2019

Credit U.S. Forest Service

The number of non-native lake trout in Yellowstone Lake is on the decline. Yellowstone biologists are optimistic that this means the native cutthroat trout population may be recovering.

Cutthroat trout are an important food source for many of the parks wildlife including grizzly bears and birds of prey. Since the population has been declining, species are moving away from the ecosystem or have to find a new source of food.

Morgan Warthin, Yellowstone National Park public affair specialists, said the park has been removing non-native trout from the lake since 1994, and the numbers are looking good.

"Park staff this year removed 282,960 fish between May and October, and that number has gone down. It's been a decline of 29% over the last three years," she said.

Warthin said there was some more encouraging finds this summer.

"This July, fishery staff found large numbers and sizes of cutthroat trout throughout county streams that are considered part of the Yellowstone Lake Ecosystem. And so we know with confidence that there has been a substantial increase in the number of cutthroat trout," Warthin said.

This is good news, but to continue this trend nonnative, non-native trout will be removed from the lake for at least five more years.

Have a question about this story? Contact the reporter, Kamila Kudelska, at kkudelsk@uwyo.edu.