Westslope Cutthroat Trout Coming Back to Yellowstone National Park

Fisheries biologists are working to return genetically pure Westslope cutthroat trout to three lakes in Yellowstone National Park. NPS file photo by Jim Ruzycki.

Westslope cutthroat trout will soon be gaining another foothold in Yellowstone National Park, where fisheries biologists are working to return the native fish to Goose Lake.

But before these trout can be put back into the lake, non-native rainbow trout must be removed. To accomplish that task, biologists last week poured a fish toxin into Goose Lake -- which is located in the Lower Geyser Basin, along the Fairy Falls Trail -- and two nearby lakes to remove the rainbow trout.

According to park officials, decades ago, the three lakes were stocked with the rainbows. Their presence contributed to a decline in native trout in park lakes, rivers and streams, in part because rainbows can breed with cutthroat trout and produce hybrid trout that are also considered a non-native species.

As part of Yellowstone’s Native Fish Conservation Plan and Environmental Assessment, which was approved in May, biologists poured the chemical Rotenone in small quantities into the lakes. Visitors are advised not to swim in or drink from the three lakes through October 15.

Next year, the park will reintroduce genetically-pure native Westslope cutthroat trout to the three lakes. The long-term plan, in addition to restoring this native species to a portion of its native habitat, is for these lakes to provide a brood stock population of the native fish for future restoration efforts.