Yellowstone Lake

Yellowstone Lake Yellowstone Lake has the largest population of wild cutthroat trout in North America. How these Pacific Ocean cutthroat got trapped in a lake that drains to the Atlantic Ocean puzzled experts for years. There is now a theory that Yellowstone Lake once drained to the Pacific Ocean (via Outlet Canyon to Snake River) and that fish could pass across the Continental Divide at Two Ocean Pass. Lake trout, an illegally introduced, exotic species, is now found in Yellowstone Lake and threatens the existence of the native cutthroat trout.