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BC Conservation Data Centre: Species Summary


Salvelinus confluentus
Bull Trout

 
Scientific Name: Salvelinus confluentus (Suckley, 1859)
English Name: Bull Trout
 
Classification / Taxonomy
Scientific Name - Concept Reference: Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp.
Classification Level: Species
Species Group: Vertebrate Animal
Species Code: F-SACO
Kingdom Phylum Class Order Family
Animalia Craniata Actinopterygii Salmoniformes Salmonidae
   
Conservation Status / Legal Designation
Global Status: G3 (Feb 2025)
Provincial Status: S3S4 (Apr 2018)
BC List: Blue
Provincial FRPA list: Y (Jun 2006)  
Provincial Wildlife Act:
COSEWIC Status: Special Concern (Nov 2012)
SARA Schedule:
General Status Canada: 3 - Sensitive (2005)
   
Ecology & Life History
General Description: Resident adults are 15-30 cm in length whereas migratory adults commonly exceed 60 cm (see Rieman and McIntyre 1993).
Global Reproduction Comments: Spawns in late summer or fall, with falling temperatures between 5 C and 9 C. Eggs hatch in late winter or early spring. Fry emerge from gravel in April or May. Most information indicates that sexual maturity is attained in 5-7 years (also reported as 4-5 years). May spawn each year or in alternate years. Spawning populations may comprise four or more year classes, though one or two year classes may dominate. See Rieman and McIntyre (1993).
Global Ecology Comments: Resident and migratory form live together but whether they represent a single population or separate populations is unknown (Rieman and McIntyre 1993).

Vigorous populations may require abundant fish forage (Rieman and McIntyre 1993).

Available information indicates that bull trout and other native fishes use different resources, reducing direct competition (Rieman and McIntyre 1993).
Migration Characteristics:
(Global / Provincial)		 
    Nonmigrant:
    Local Migrant:
    Distant Migrant:
    Within Borders Migrant: 		Y /
Y /
N /
na /
Global Migration Comments: Two distinct forms, resident and migratory, exist throughout the range (Rieman and McIntyre 1993). Migratory form migrates between spawning and nonspawning habitats; migrates upstream to spawning areas in spring. Anadromy has not been documented but may have been important in the past (see Rieman and McIntyre 1993).
Habitats:
(Type / Subtype / Dependence)
Global Habitat Comments: Habitat includes the bottom of deep pools in cold rivers and large tributary streams, often in moderate to fast currents with temperatures of 45-50 F; also large coldwater lakes and reservoirs. In the contiguous U.S., now extirpated in most large rivers that historically were inhabited; confined mostly to headwater streams. Conditions that favor the persistence of populations include stable channel, relatively stable stream flow, low levels of fine substrate sediments, high stream channel complexity with various cover types, temperatures not exceeding about 15 C, and the presence of suitable corridors for movement between suitable winter and summer habitats and for genetic exchange among populations (Rieman and McIntyre 1993).

Migratory forms live in tributary streams for up to several years before migrating downstream into a larger river or lake, where they spend several years before returning to tributaries to spawn (Rieman and McIntyre 1993). Some or most juveniles move to larger rivers or to a lake by mid-summer, while others stay in spawning areas for 2-4 years (Spahr et al. 1991). Adults return to river or lake after spawning in small streams. May move to lower reaches of mainstream river for winter. Resident populations often occur in small headwater streams where they spend their entire lives (see Rieman and McIntyre 1993). In lakes, inhabits all depths in fall, winter, and spring; moves to cooler, deeper water for summer.

Spawning usually occurs in gravel riffles of small tributary streams, including lake inlet streams. Spawning sites often are associated with springs (Rieman and McIntyre 1993). According to California Department of Fish and Game (1990), spawning requires a large volume of cold water. Optimum temperatures for incubation are about 2-4 C (see Rieman and McIntyre 1993). Constructs spawning redd. Young are closely associated with stream channel substrates (Rieman and McIntyre 1993). Areas with large woody debris and rubble substrate are important as juvenile rearing habitat (Spahr et al. 1991).
Food Habits: Carnivore: Adult, Immature
Invertivore: Adult, Immature
Piscivore: Adult, Immature
Global Food Habits Comments: Eats terrestrial and aquatic insects, macrozooplankton, mysids, and fishes. Young feed heavily on aquatic insects. Adults feed principally on fishes, but have also been known to eat other small vertebrates, including frogs, snakes, mice, ducklings, etc. (Moyle 1976).
Global Phenology:
Provincial Phenology:
(1st half of month/
2nd half of month)
Colonial Breeder: N
Length(cm)/width(cm)/Weight(g): 90/ /
Elevation (m) (min / max): Global: 
Provincial: 
   
 
Distribution
Endemic: N
Global Range Comment: This species is found in western North America in river drainages on both sides of the Continental Divide from Yukon Territory, Canada south southeastern Oregon and extreme northern Nevada, United States (Lee et al. 1980, Page and Burr 1991, USFWS 2024). Using RARECAT (2024) to assess Global Biodiversity Information Facility (GBIF) (2025) records from 2005-2025, range extent is estimated to be 1,556,486 kmē.

This species is extirpated from the McCloud River drainage in California and this portion of the range is not included in this assessment (Minckley and Deacon 1991).
 
Authors / Contributors
Global Information Author: Hammerson, G.
Last Updated: Nov 04, 2011
Provincial Information Author:
Last Updated:
   
References and Related Literature
Baxter, J.S., and J.D. McPhail. 1996. Bull Trout Spawning and Rearing Habitat Requirements: Summary of the Literature. B.C. Minist. Environ., Lands and Parks. 25pp.
Bray, K. 2001. Lake Revelstoke Reservoir Bull Trout Radio Telemetry, Progress Report 2001-2002. Columbia Basin Fish and Wildl. Compensation Program. 20pp.
Brewin, M.K. 2004. Bull Trout Management and Recovery in Alberta In T.D. Hooper, ed. Proc. of the Species at Risk 2004 Pathways to Recovery Conf. March 2-6, 2004, Victoria, B.C. Species at Risk 2004 Pathways to Recovery Conference Organizing Committee, Victoria, BC. 22pp.
Brown, C. J. D. 1971. Fishes of Montana. Big Sky Books, the Endowment and Research Foundation, Montana State University, Bozeman. MT. 207 pp.
California Department of Fish and Game (CDF&G). 1990. 1989 annual report on the status of California's state listed threatened and endangered plants and animals. 188 pp.
Donald, D. B., and D. J. Alger. 1993. Geographic distribution, species displacement, and niche overlap for lake trout and bull trout in mountain lakes. Canadian Journal of Zoology 71:238-247.
Forest Practices Code. 1997. Bull Trout in Species and Plant Community Accounts for Identified Wildlife: Vol. 1. B.C. Minist. For. and B.C. Environ. 184pp.
Lee, D. S., C. R. Gilbert, C. H. Hocutt, R. E. Jenkins, D. E. McAllister, and J. R. Stauffer, Jr. 1980. Atlas of North American freshwater fishes. North Carolina State Museum of Natural History, Raleigh, North Carolina. i-x + 854 pp.
McClaren, E. 1993. Fisheries status report for the Peace Sub-Region (B.C. Environment, Region 7): bull trout (Salvelinus confluentus). Unpubl. rep., Fish and Wildl. Program, B.C. Environ., Fort St. John, BC. 23pp. plus appendices.
Minckley, W. L., and J. E. Deacon. 1991. Battle Against Extinction: Native Fish Management in the American West. University of Arizona Press, Tucson. xviii + 517 pp.
Moyle, P. B. 1976a. Inland fishes of California. University of California Press, Berkeley, California. 405 pp.
O'Brien, D.S. 2001. Bull Trout Spawning Migrations in the Duncan River: Insights from Telemetry and DNA. Columbia Basin Fish and Wildl. Compensation Program, BC Hydro, B.C. Gov. 91pp.
Page, L. M., and B. M. Burr. 1991. A field guide to freshwater fishes: North America north of Mexico. Houghton Mifflin Company, Boston, Massachusetts. 432 pp.
Rieman, B. E., and J. D. McIntyre. 1993. Demographic and habitat requirements for conservation of bull trout. USDA Forest Service, Intermountain Research Station, Gen. Tech. Rep. INT-302. 38 pp.
Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and W.B. Scott. 1991. Common and scientific names of fishes from the United States and Canada. American Fisheries Society, Special Publication 20. 183 pp.
Scott, W. B., and E. J. Crossman. 1973. Freshwater fishes of Canada. Fisheries Research Board of Canada, Bulletin 184. 966 pp.
Simpson, J. and R. Wallace. 1982. Fishes of Idaho. The University Press of Idaho, Moscow, Idaho. 238 pp.
Spahr, R., L. Armstrong, D. Atwood, and M. Rath. 1991. Threatened, endangered, and sensitive species of the Intermountain Region. U.S. Forest Service, Ogden, Utah.
Starnes, W. C. 1995. Taxonomic validation for fish species on the U.S. Fish and Wildlife Service Category 2 species list. 28 pp.
Stoltz, J., and J. Schnell (eds.). 1991. Trout: The Wildlife Series. Stackpole Books, Harrisburg, Pennsylvania. 384 pp.
Thomas, J. W., Ward, J., Raphael, M.G., Anthony, R.G., Forsman, E.D., Gunderson, A.G., Holthausen, R.S., Marcot, B.G., Reeves, G.H., Sedell, J.R. and Solis, D.M. 1993. Viability assessments and management considerations for species associated with late-successional and old-growth forests of the Pacific Northwest. The report of the Scientific Analysis Team. USDA Forest Service, Spotted Owl EIS Team, Portland Oregon. 530 pp.
Troffe, P. 1999. Freshwater Fishes of the Columbia Basin. Royal B.C. Mus. 102pp.
U.S. Fish and Wildlife Service (USFWS). 10 June 1998. Proposal to list the coastal-Puget Sound, Jarbridge River and St. Mary-Belly River population segments of bull trout as threatened species. Federal Register 63(111):31693-31710.
U.S. Fish and Wildlife Service (USFWS). 13 June 1997. Proposal to list the Klamath River population segment of bull trout as an endangered species and Columbia River population segment of bull trout as a threatened species. Federal Register 62:32268-32284.
U.S. Fish and Wildlife Service (USFWS). 1998. Endangered and threatened wildlife and plants; determination of threatened status for the Klamath River and Columbia River distinct population segments of bull trout. Federal Register 63(111):31647-31674.
U.S. Fish and Wildlife Service (USFWS). 1999a.  Endangered and threatened wildlife and plants: determination of threatened status for the Jarbridge River population segment of bull trout. Federal Register 64(67):17110-17125.
U.S. Fish and Wildlife Service (USFWS). 1999b. Endangered and threatened wildlife and plants; determination of threatened status for bull trout in the conterminous United States. Federal Register 64(210):58910-58933.
 

Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.

Suggested Citation:

B.C. Conservation Data Centre. 2011. Species Summary: Salvelinus confluentus. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 14, 2026).