Bull trout used to live in many streams in the Boise National Forest. But their habitat has been ruined over the last 100 years. Bull trout populations have decreased. Now, they are a threatened species - not yet endangered.

The Forest Service and Idaho Fish and Game are working together to keep bull trout from becoming extinct.

What's causing bull trout habitat changes?

Grazing sheep and cattle and harvesting trees removed plants and trees that shaded streams. Unshaded, the stream temperature was too warm for bull trout. (They like cool water - about 45º F.)

Plants also helped hold the soil in place. With the plants gone, the soil washed into the streams. Bull trout like clean water with little sediment.

Other changes to their habitat include: Dams which blocked fish migration paths. Mining has reduced water quality. Non-native fish compete for bull trout habitat. Overfishing - many people can't tell the difference between bull trout and other trout. When they catch a bull trout they keep it, thinking it's some other trout.

Not So Cool Fact: There is a $200 fine for catching and keeping a bull trout.

How to identify bull trout:
- no spots on tail or top fin
- white stripe on edge of bottom fins

Where do you find bull trout? In cold, clear streams high in the mountains. You'll see bull trout hanging out in pools, along stream banks and at the bottom of streams. They like to hide around dead tree branches in streams.

There are 2 types of bull trout in Idaho's streams. Some bull trout spend their whole lives in the same small stream they grew up in. Other bull trout migrate from the small streams to rivers and lakes. They come back to the little streams to spawn. Bull trout that migrate can get really big - up to 40 inches!

Very cool facts about bull trout:

- Bull trout is a predator - they eat other fish, even snakes and frogs!
- They have large jaws that can open wide.
- They can grow up to 40 inches long and weigh 30 pounds.
- They can live to be 20 years - longer than any other trout, char or salmon.