The average length is variable, but most adults seem to vary from 12-18 inches (30-45 cm) and weigh 2-5 pounds. Their colour is variable with size , locality and habitat. Back and upper sides are olive-green to brown, with the sides a paler colour and underside white to dusky. The dorsal surface and sides are marked with numerous yellow, orange or red spots.

Columbia Basin: Widely distributed throughout the Columbia Basin

British Columbia: Bull trout is an interior species in B.C. They are widely distributed throughout the province, but are absent from the western tributaries of the Columbia River, such as the Okanagan, Kettle and Similkameen rivers (Cannings and Ptolemy, 1998).

Global: Bull Trout are endemic to western North America from northern California to Yukon, and east as far as western Alberta and Montana.

Habitat requirements vary with the life history of individual stocks (Cannings and Ptolemy, 1998). In rivers, deep pools are required with large woody debris and other cover elements such as cutbanks, boulders or overhanging trees. Bull Trout appear to be selective about spawning sites. They prefer clean gravel and cobble substrates adjacent to cover sites.

Bull Trout are declining, particularly in the southern and eastern parts of their range. They are extremely sensitive to habitat degradation and are considered and indicator of ecosystem health. (Cannings and Ptolemy, 1998). They are a cold water species, preferring temperatures less than 15°C. Human activities and developments that cause changes in temperature, substrate composition, habitat, or migration patterns increase the vulnerability of the species, e.g. logging, mining, hydro development, urban expansion. They are also threatened by genetic swamping from introduced trout and char.

According to Cannings and Ptolemy, (1998), there are four possible life-history patterns: 1) a stream resident form that lives its life in small headwater streams; 2) a fluvial-adfluvial form resides as an adult in large rivers but migrates long distances to spawn in small tributaries; 3) a lacustrine0-adfluvial form lives as an adult in lakes and spawns in tributaries; and, 4) anadromous bull trout may occur in some systems entering the Strait of Georgia. The stream resident form reaches sexual maturity at a young age and remains small in size. Both the fluvial-adfluvial and lacustrine-adfluvial forms mature later in life and reach larger size. Migrant and resident forms can occur together. Spawning occurs in September and October, but varies with geographic distribution.