Bull Trout Color Plate - Bull Trout Color Plate

The native bull trout has been determined to be a separate species from the coastal Dolly Varden. Bull trout are found in the Clark Fork and Flathead drainages of western Montana, and their slowly declining trend has led to their designation as a threatened species. Bull trout are a sensitive species that do not tolerate high sediment levels in their spawning streams. Sediment can suffocate the developing embryos before they hatch. In Flathead Lake, where they achieve trophy sizes of up to 25 pounds, the bull trout life cycle has been studied extensively. Adult bull trout ascend the North and Middle forks of the Flathead River to spawn in small tributary streams; in some cases traveling well over 100 miles in a few months. They spawn in the fall and the adults return to the lake. Young fish may spend up to three years in the tributaries before returning to mature in Flathead Lake. In other river systems, bull trout may be a resident stream fish.

Often, native bull trout have been displaced through competitive interaction with introduced brook trout. Bull trout and brook trout will interbreed, resulting in sterile hybrids, which leads to a further decrease in bull trout populations. The bull trout may be considered the grizzly bear of the fish world in relationship to its need for unaltered habitat. Young bull trout feed primarily on aquatic invertebrates but adults eat mostly other fish (FWP). Resident adults are 15 to 30 centimeters in length whereas migratory adults commonly exceed 60 centimeters (Rieman and McIntyre 1993).

Visit the Montana Animal Field Guide for more information on the Bull Trout

Species of Montana

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• Upland Game Bird Program

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The restoration of its world-renowned elk population has been one of Montana’s greatest wildlife management success stories. Over the past century wildlife managers, hunters, ranchers, and others have helped rebuild a population from only a few thousand animals to one now esti­mated at over 150,000. The elk recovery did not come easily. [Full Story]

Follow That Bear

“It’s a wonder we get any of these collars out,” says Rick Mace as he describes the difficulty of capturing female grizzly bears and fitting them with collars containing GPS (Global Positioning System) transmitters. For the past three years, the Montana Fish, Wildlife & Parks bear biologist has been studying grizzly population trends in Montana’s Northern Continental Divide Ecosystem (NCDE), which encompasses Glacier National Park and the Bob Marshall Wild­erness south to the Blackfoot Valley. The study requires that Mace and his crew regularly trap bears, which have to be grizzlies, not black bears. The captured bears must also be female, not male. And each animal’s neck must be large enough so the collar doesn’t slip off. “Trapping the right bear is like trying to find a needle in a haystack,” says Mace. Unfortunately, there is no other way to learn if NCDE grizzly numbers are rising, falling, or holding steady—vital information for determining the health of the grizzly population. [Full Story]

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