The National Park Service is recommending suppression of non-native fish to assure successful reintroduction of westslope cutthroat trout and fluvial arctic grayling in Yellowstone National Park.
That tactic is the preferred alternative in the new environmental analysis of plans to restore the two native species that, while not endangered, are on the verge of disappearing from the Yellowstone ecosystem.
The analysis does not propose specific reintroduction actions but sets a goal of developing annual plans to describe sites considered to have a high probability of successful reintroduction.
Yellowstone superintendent Mike Finley said methods that would be used to remove non-native species could include chemical treatment, electrical stunning, netting, trapping and sport fishing.
The westslope cutthroat - a different species than the native Yellowstone cutthroat that lives in Yellowstone Lake and most park streams - and the arctic grayling have historically inhabited the Madison and Gallatin rivers, and the Gibbon River downstream of Gibbon Falls and their tributaries.
But the populations have declined steadily throughout their historic ranges over the past two decades.