Bull Trout

Salvelinus confluentus

OTHER NAMES

Dolly Varden Dolly

Bull Trout bull charr, western brook trout, Rocky Mountain trout, red spotted salmon-trout, red spotted charr.

Distribution. Dolly Varden occur from the Sea of Japan, throughout the Kuril Islands to Russia's Kamchatka Peninsula, throughout the Aleutian Islands, and around Alaska and the Yukon Territory to the Northwest Territory, as well as in the northwestern United States. In North America, they are especially abundant in Alaska and parts of British Columbia.

The bull trout is endemic to the Pacific Northwest and inhabits most of the significant drainages on both sides of the Continental Divide. It seems to prefer large, cold rivers and lakes draining high mountainous areas and tends to frequent the bottoms of deep pools. It has been recorded in

Dolly Varden and Bull Trout northern California, Oregon, Washington, northern Nevada, Idaho, western Montana, Alberta, and British Columbia.

Habitat/Life history. Bull trout and Dolly Varden prefer deep pools of cold rivers, lakes, and reservoirs. Streams with abundant cover (cut banks, root wads, and other woody debris) and clean gravel and cobble beds provide the best habitat. Their favored summer water temperature is generally less than 55°F, but they nevertheless tolerate temperatures less than 40°F. Spawning during the fall usually starts when water temperatures drop to the mid- to low 40s. Cold, clear water is required for successful reproduction.

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darker than the pale sides; cream to pale yellow spots (slightly smaller than the pupil of the eye) cover the backs, and red or orange spots cover the sides; and the pectoral, pelvic, and anal fins have white or cream-colored margins. The male in full fall spawning dress sports a dark olive back, sometimes bordering on black; an orange-red belly; bright-red spots; and fluorescent white fin edges, rivaling fall's spectacular colors. Sea-run Dollies are silvery, and the spots can be very faint.

Size. Sea-run Dolly Vardens generally range from 1 to 3 pounds, and freshwater specimens seldom weigh more than 8 pounds. The all-tackle world record is a 20-pound, 14-ounce Alaskan fish. Bull trout are larger growing than Dollies, although the typical fish weighs between 2 and 5 pounds. The all-tackle world record is a 32-pounder that was 40V2 inches long and was caught in Lake Pend Oreille, Idaho, in 1949.

Life history. Bull trout and Dolly Varden have complex but similar life histories. Anadromous (seagoing) and migratory resident populations (for example, lake-dwelling stocks and main-stem rearing stocks) often journey long distances in the summer and the fall to spawn, migrating to the small headwater streams where they hatched. Mature adults with these characteristics are generally 4 to 7 years old and 18 to 22 inches in length when they make their first spawning run, although they may be older in some populations.

Spawning begins in late August, peaks in September and October, and ends in November. Fish in a given stream spawn over a short period of time, 2 weeks or less, making redds in clean gravel. Almost immediately after spawning, adults begin to work their way back to the main-stem rivers, lakes, or reservoirs to overwinter. Some of these fish stay put; others move on to saltwater in the spring, evidently not wandering far.

Food. Bull trout and Dolly Varden are opportunistic feeders, eating aquatic insects, shrimp, snails, leeches, fish eggs, and fish.

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