Anglers need to be sure you are keeping only lake trout. If you keep a bull trout by mistake you can be cited and fined. So go through the lake trout identification tips by clicking on the buttons below. That way you’ll know how to ID lake trout.
Tails of adult
lake trout have a pronounced V-shape.
Lake trout have a dorsal or back fin that has black or gray markings.
Markings on the Back
Lake Trout have irregular markings, bull trout have distinct spots
Compare the Two
Check the tail, check the dorsal fin, check the spots
Pick out the Bull Trout
With smaller fish, it can be hard to distinguish between bull trout and lake trout, as with the two fish in the photo above. Which is which? Take a guess then get the answer by clicking the button below.
The one on the left is a bull trout, the one on the right a lake trout. Note the more deeply forked tail of the lake trout. But it can be hard to tell. Check the fish’s back. If it has distinct, uniformed, rounded spots on its back, it’s a bull trout. And check the dorsal or back fin. If it lacks black or gray markings, it’s a bull trout—throw it back!
For thousands of years, bull trout have traveled some of the longest migration routes of any trout in North America. Once common throughout the inland Pacific Northwest, bull trout now live in reduced numbers in five western states and two Canadian provinces. They no longer live in California. Montana and Idaho are the bull trout's strongholds, but even here bull trout face possible extinction in some streams.
One very important thing that you can do to help minimize the impact that we humans have on the bull trout, is to learn to correctly identify the fish that you catch, and also the fish that you see swimming in Montana's waters. Correct identification, both in and out of the water, will help you release the right fish and avoid hooking a bull trout by accident. Bull trout are protected by both state and federal law; there is no fishing season for them (except in northwestern Montana's Swan Lake) and they have been listed since 1998 as threatened by the U.S. Fish and Wildlife Service. Intentionally or accidentally “taking” a bull trout is illegal. It also creates an unfavorable public image of fishermen and fishing.
No black spots on the dorsal fin, put it back! Adult bull trout
Bull Trout are a Threatened Species listed under the Endangered Species Act.
Montana law requires all bull trout caught in Flathead Lake be released immediately.
When handling fish wet your hands—be very careful—do not put your fingers in the gills of the fish. If your hook does not easily come out, clip the line and leave the hook inside the fish. The hook will eventually dissolve.
Check the dorsal fin. If there is "no black", put it back. ("No black" means no black spots.) Smaller bull trout are very hard to identify. Look at the fish along the top of the back. If the spots are uniform and lined up it is probably a bull trout. Spread the tail — it may look like it is not flat but when you spread it out it may take on a flatter appearance. If it does it is a bull trout.
If you are in doubt-throw it out!!
If you are fishing an area where you have caught several bull trout, you should move to another location. Don't stay in that area and continue to catch bull trout. It is illegal to target or harvest a bull trout in Flathead Lake. Use separate coolers to keep track of your fish if you are fishing with another person so you don’t get blamed for catching a fish you didn’t catch. We are required to report bull trout violations to the enforcement authorities. Many contestants have received fines and if the number of bull trout killed becomes too large it may jeopardize the future of the contests.