Bull Trou, US Fish &  Wildlife photoBull Trout, NPS photoJuvenile Bull Trout, US Fish & Wildlife  photo

Bull trout (Salvelinus confluentus), listed as threatened under the Endangered Species Act since 1998, are present in the Crown of the Continent on both sides of the continental divide. They generally require water temperatures below 55 degrees F (13 degrees C), clean gravel bottoms, deep pools and complex cover. They can be found in lakes and rivers, as well as high mountain headwaters.

Current research on bull trout is focused on threats to the species. Increasing water temperatures due to climate change and human impacts due to road building and logging is reducing available habitat. Hybridization and competition from non-native fish are also being studied as these impacts have reduced bull trout population numbers. Studies concerning these threats are underway with the goal of reducing their impacts on native bull trout and the ecosystem which supports them.