Many spawning areas are associated with cold water springs or areas where stream flow is influenced by groundwater. They spawn in the fall after temperatures drop below 48° Fahrenheit (8☌), in streams with cold, unpolluted water, clean gravel and cobble substrate, and gentle stream slopes. Bull trout evolved with whitefish, sculpins and other trout and use all of them as food sources.īull trout reach sexual maturity between four and seven years of age and are known to live as long as 12 years.

Large bull trout are primarily fish predators. Small bull trout eat terrestrial and aquatic insects but shift to preying on other fish as they grow larger. In Washington, both species are present in the Puget Sound area. Bull trout are mainly an inland species, while Dolly Varden are more common in coastal areas. Compared to Dolly Varden, bull trout are larger on average, with a relatively longer and broader head. Both species also exhibit differences in size, body characteristics, coloration, and life history behavior across their range.Taxonomic work, published in 1978 and accepted by the American Fisheries Society in 1980, identified bull trout as distinct from the Dolly Varden. Spawning adults develop varying amounts of red on the belly.

Both have small, pale yellow to crimson spots on a darker background, which ranges from olive green to brown above, fading to white on the belly. Bull trout and Dolly Varden look very similar, and were once considered the same species. The bull trout has small, pale yellow-to-crimson spots on a darker background, fading to white on the belly. The main populations remaining in the lower 48 states are in Montana, Idaho, Oregon, and Washington, with a small population in northern Nevada. Species summary and status: The bull trout was once found throughout the Columbia River Basin, east to western Montana, south to northern Nevada, west to California and possibly as far north as southeastern Alaska. Sign Up for Auto-Renewal & Sustainer Giving.

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