Bull trout (Salvelinus confluentus) swimming in the Bighorn Creek, in the Wigwam River drainage in British Columbia. This is one of the last, best places for spawning of the fedearlly-threatened bull trout, and is part of the Kootenay River system, which sees an annual migration of bull trout from Lake Koocanusa, some fifty miles away. The fish prefer very cold water of 40 degrees or so in order to spawn, and the springs in this area provide that.