Bull Trout South Coast British Columbia populations
Scientific Name: Salvelinus confluentus
Taxonomy Group: Fishes
Range: British Columbia
Last COSEWIC Assessment: November 2012
Last COSEWIC Designation: Special Concern
SARA Status: No schedule, No Status
Image of Bull Trout
The Bull Trout (Salvelinus confluentus) belongs to the salmon and trout family (Salmonidae) and is part of the char subgroup that also includes Dolly Varden (S. malma). Various life history strategies are employed by this species, which include: 1) stream resident, 2) fluvial, 3) adfluvial, and 4) anadromous. There are five Designatable Units (DUs) of Bull Trout in Canada, which represent discrete and evolutionarily significant units of the species. The anadromous life history form is unique to the Southcoast British Columbia populations DU, which has been assessed as Special Concern by the Committee on the Status of Endangered Wildlife in Canada. General characteristics include: • Long and slender body; • Large broad head and prominent upper jaw; • Slightly forked tail fin; • Olive-green to blue-grey back; • Silvery sides with small pink, lilac, yellow-orange or red spots; • Pale belly that may become yellow, orange or red in spawning males; • White leading edges on the pelvic and anal fins, with no black line; and • Variable size at maturity dependent upon life history. Stream resident populations average length are 250 mm (maximum 410 mm); fluvial populations are greater than 400 mm (maximum 730 mm); and adfluvial populations are also greater than 400 mm (maximum 900 mm). Anadromous populations may be larger still.
Distribution and Population
Bull Trout are residents of the Pacific Northwest. In the United States, they are found from northern Nevada through Oregon, Idaho, Montana, and Washington. The Canadian distribution extends from western Alberta throughout most of British Columbia, with a northern limit into the southern Yukon and the central portion of the Northwest Territories. Southcoast British Columbia populations inhabit the Skagit, Squamish, Ryan, Lillooet, Pitt and Lower Fraser Rivers, the Pitt, Birkenhead, Chilliwack, and Chehalis Lakes, and Phelix and Ure Creeks. In British Columbia the status of populations is stable to diminishing.
The Bull Trout is a cold-water (usually <18°C) species found in lakes, streams and rivers from sea level to mountainous areas. Its habitat has been described by the U.S. Fish and Wildlife Service as “cold, clean, complex and connected.” A stream resident form spends its life in small rivers or streams, usually isolated by barriers. The fluvial form spawns in smaller tributaries but spends the remainder of the life cycle in larger rivers. The adfluvial form is similar, but matures in lakes or reservoirs. The anadromous form, which is found only in southwestern British Columbia and northwestern Washington, migrates from natal freshwater streams to feeding habitat at sea. Cover is extremely important to these ambush predators. Fry tend to be found in shallow side channels while rearing juveniles appear to prefer pool habitats. Overwintering habitat consists of deep pools, in order to avoid interactions with ice. Preferred spawning areas are usually cold (~5 to 10°C), clean, and small flowing streams with cobble or loose gravel substrates.
Biological characteristics of the Bull Trout, such as body size and diet for example, can be highly variable depending on the various life history strategies employed. Bull Trout are opportunistic feeders, however juveniles tend to prefer aquatic insects and invertebrates, and adults generally prey on fish. Sexual maturity is reached between 3 – 8 years, at which time spawning is carried out between mid-August and late October; homing behaviour has been observed in some individuals. Spawning occurs over a period of several days at redd (gravel nest) sites selected and excavated by females. Bull Trout are iteroparous, meaning they can reproduce more than once during their lifespan.
Habitat degradation and fragmentation, introduced species, and overexploitation are the primary threats to Southcoast British Columbia populations. Increased development (e.g., oil and gas development, forestry, mining, transportation infrastructure and hydroelectric projects) may disrupt migration, or increase water temperatures and siltation rendering the species vulnerable. Displacement by or hybridization with Brook Trout is also a particular concern. And, increased road access to previously remote populations, high catchability, and similar appearance to Dolly Varden render them vulnerable to exploitation.
In Canada, the species is afforded protection under the Fisheries Act, and is currently under consideration for listing as Special Concern under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available online at www.AquaticSpeciesAtRisk.ca or on the SARA Registry at www.SaraRegistry.gc.ca.
Provincial and Territorial Protection
Other Protection or Status
Provincially, the Bull Trout is on the Blue List in British Columbia. In addition, the Fish Protection Act and Forest and Range Practices Act support the management of this species.
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
3 record(s) found.
- COSEWIC Status Reports (1 record(s) found.)
- Response Statements (1 record(s) found.)
- COSEWIC Annual Reports (1 record(s) found.)
COSEWIC Status Reports
COSEWIC Annual Reports
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