Species Information

Pictures Courtesy of Joseph Tomelleri

Species Distribution in Montana

Brown Trout - Salmo trutta

The brown trout belongs to a different genus than our native trout species. They evolved in Europe and western Asia and were introduced to North America in 1883 and to Montana in 1889 in the Madison River. Today brown trout are found throughout most of Montana except the northwest and parts of the east. Generally, they prefer lower gradient, larger streams than cutthroat and rainbow, and they also do well in many reservoirs.

Brown trout were widely stocked in the first half of this century, but today most come from natural reproduction. Brown trout are great competitors and generally are more tolerant of dewatering and other environmental disturbances than our other trout species. Brown trout spawn in gravel redds like our native trout but their spawning season is in the fall. This gives them a distinct advantage in some habitats since their spawning and incubation period lies outside the irrigation season.

Rainbow Trout - Oncorhynchus mykiss

The rainbow trout is Montana's number one game fish. Rainbow trout were introduced from numerous hatchery stocks into virtually every suitable habitat in the state, beginning in 1889. Scientists believe that only the rainbow trout of the upper Kootenai River drainage are native to this state. This small group of natives are a Fish of Special Concern.

Rainbow trout introductions have caused a severe reduction in the range of the native cutthroat trout through hybridization and competition. Rainbow trout fare well under a wide range of habitat conditions from ponds to reservoirs, lakes, and streams. Rainbow are efficient at feeding on plankton, aquatic and terrestrial insects, and occasionally some smaller fishes. They spawn in early spring in running water, usually April or May, and maintain themselves quite nicely if the habitat is not degraded.

Brook Trout - Salvelinus fontinalis

The "brookie" or brook trout was introduced to Montana from eastern North America in 1889. It too, was extensively propagated and stocked in the early half of this century, although seldom so today.

Brook trout favor small, cold, headwaters streams and ponds, particularly those that are spring-fed. Brook trout are common throughout most of the western two-thirds of the state in all major drainages. Brook trout are frequently able to spawn successfully in ponds which have upwelling springs. Brook trout will eat nearly any living organism, and larger fish can be voracious predators on other fish and even their own young. The offspring, called tiger trout, have the markings of a tiger or giraffe. They are very rare since mortality of eggs and newly hatched fish is high and hybrids reaching adulthood are usually sterile.

Prefers small spring fed streams and ponds with sand or gravel bottom and vegetation. Spawns over gravel in either streams or lakes with percolation;spring areas in lakes. Often overpopulates, resulting in fish too small to attract anglers.

Lake Trout - Salvelinus namaycush

The lake trout is a char of the same genus as bull trout and brook trout. Lake trout are native in the St. Mary and Missouri River drainages and have been introduced to a few other scattered mountain lakes, Flathead Lake, and Fort Peck Reservoir.

Lake trout inhabit very deep, cold lakes, living in water up to 200 feet deep. They spawn in the fall on the rocky substrate of the shoreline. They scatter or broadcast their spawn, a rarity in the trout group. Small lake trout feed on plankton and aquatic invertebrates but fish over 2 to 3 pounds eat a fish diet.

Golden Trout - Oncorhynchus mykiss aguabonita

The golden trout is a California species that was introduced in Montana in 1907. There are currently about 20 golden trout populations in the high mountain lakes of western and south central Montana. They provide a unique opportunity to catch a beautiful fish in a pristine environment. Golden trout up to 4 pounds have been caught in Montana but typical size is usually 6-12 inches. Golden trout are spring spawners and can usually be found in inlet or outlet streams to high mountain lakes around the Fourth of July.

Found only in mountain lakes in Montana; also successful in clear, cool lakes at lower elevations. Spawns in redds over clean gravel of fist size and smaller. Spawns mostly in outlets, but also in inlets and occasionally along lake shoals. Readily hybrizes with cutthroat and rainbow. Demise of former 50+ populations of golden trout largely due to introduction of other spring spawning species, whether by hybridization or replacement.