Steelhead Trout Thompson River population
Scientific Name: Oncorhynchus mykiss
Taxonomy Group: Fishes
COSEWIC Range: British Columbia, Pacific Ocean
COSEWIC Assessment Date and Status Change: November 2020
COSEWIC Status: Endangered
COSEWIC Status Criteria: A2bcde+3bcde+4bcde; B2ab(iii,v); C1+2a(i,ii); D1
COSEWIC Reason for Designation: This population is among the longest migrating anadromous trout in Canada. It migrates from the headwaters of the Thompson River to the Bering Sea, returning after two years to swim up the Fraser River in the fall. Within the Thompson River watershed, this population is culturally significant and was an economic and food resource for Secwépemc and Nle?kpmx communities for thousands of years. Dramatic population declines over the last three generations are largely a consequence of declining habitat quality and reduced survival rates while at sea, due to factors such as interception by fisheries, competition from hatchery fish, and possible predation from pinnipeds. The returning numbers of spawners are now very low and future population reductions are expected.
COSEWIC History of Status Designation: Designated Endangered in an emergency assessment conducted on January 10, 2018. Status re-examined and confirmed in November 2020.
SARA Status: No schedule, No Status
Date of Listing (yyyy-mm-dd):
Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.
Fishes [Updated 2018-02-16]
Steelhead Trout (sometimes referred to as “Steelhead Salmon”) is the anadromous form (i.e. fish which migrate from marine to freshwater environments to spawn) of Rainbow Trout (Onchorhynchus mykiss), which is a salmonid found in freshwater tributaries to the Pacific Ocean. Steelhead Trout have a similar appearance to Rainbow Trout, especially during earlier life cycle stages. Individuals of this species can vary in colouration depending on how much time they have spent in freshwater as opposed to the marine environment. With a shorter length of time spent in freshwater, a Steelhead will appear similar to Pacific Salmon, having dark blue backs with spots and silver sides. The longer time spent in freshwater, the more a Steelhead looks like a Rainbow Trout: bright silver with orange and pink tints amongst its scales. As adults, Steelhead range from 50 to 85 centimetres in length and have a more streamlined, torpedo-shaped body than resident Rainbow Trout. Steelhead Trout are also distinguished from resident Rainbow Trout by their older age of maturity and larger size. The average Steelhead lifespan is nine years. However, some Steelhead may reach an age of over 13 years. Steelhead can spawn repeatedly during their lifespan. At maturity, the male’s jaw will grow long and develop a knob at its tip (also known as a “kype”), similar to Pacific Salmon. As they prepare to spawn, Steelhead acquire a pink or red lateral line that extends over the gill covers, and their overall colouration darkens to grey or brown. [Updated 2018-02-16]
Distribution and Population
The global range of Steelhead Trout is in the coastal waters and tributary streams of the Pacific basin, from the Kamchatka Peninsula in Russia, east along the Aleutian Islands, throughout southwest Alaska, the Pacific coast of British Columbia and southeast Alaska, and south along the west coast of the United States to northern Mexico. In Canada, Steelhead Trout are found in larger British Columbia watersheds, with long distance ocean migrations. Based on genetic data, Steelhead Trout in the Thompson River and Chilcotin region are considered discrete from other Canadian Steelhead Trout. Furthermore, DNA studies have concluded that Thompson and Chilcotin Steelhead are genetically distinct from each other. As such, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has determined that Thompson River Steelhead and Chilcotin River Steelhead should be assessed as two distinct designatable units (DUs). [Updated 2018-02-16]
Eggs are deposited into redds in clean gravel located in fast-flowing riffle habitat. Newly hatched alevin rely on this gravel habitat and remain in it until they emerge as fry. Fry spend time in their natal tributary stream and potentially in the Thompson River mainstem, primarily in glide and pool habitat, before entering the marine environment as smolts. Suitable Steelhead Trout freshwater habitat depends on prey availability as well as water quality conditions such as dissolved oxygen, temperature, and pH; eggs and alevin have higher requirements for these attributes than other life stages. Marine habitat for Steelhead is also subject to these conditions as well as salinity. [Updated 2018-02-16]
Female Steelhead Trout deposit approximately 9,000 to 12,000 eggs in one or more redds in clean gravel. Within four to six weeks, eggs hatch as alevin, remaining in the gravel for another three to four weeks, at which point they emerge as fry in early to midsummer. Steelhead fry will remain in their natal stream for one or two more summers to feed and grow. Some fry will leave their natal stream earlier to spend a year in the mainstem of the Thompson River before migrating to the marine environment. Prey for fry include crustaceans and insects such as mayflies, caddisflies, and black flies. Steelhead predators in the freshwater environment include larger fish, fish-eating birds, and mammals such as otters. When Steelhead reach 15 to 20 centimetres in length, they begin their springtime migration through the Fraser River to its mouth. During their maturation stage in the marine environment, Steelhead Trout feed extensively on primarily fish, squid, and amphipods in order to gain weight and strength. In the marine environment, Steelhead are vulnerable to predators such as pinnipeds, sea lamprey, and humans. Thompson Steelhead stocks have declined considerably over the last three generations and are now at their lowest on record. The 177 mature fish observed in the most recent survey (2017) represent 9.5 percent of the pre-2000 mean. [Updated 2018-02-16]
Thompson Steelhead Trout face a number of threats, including declining habitat quality in both freshwater and marine environments, and bycatch mortality from salmon fisheries. [Updated 2018-02-16]
Provincial and Territorial Protection
Pacific Region Species at Risk Program-Steelhead Trout
DFO Pacific Region - MPO région du Pacifique - Chair/Contact - Fisheries and Oceans Canada
Recovery Progress and Activities
On December 7, 2017, the Chair of the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) informed the Minister of Environment and Climate Change Canada that COSEWIC would engage in an emergency assessment (EA) of the Interior Steelhead Trout (Thompson and Chilcotin populations) of the south central interior of British Columbia, per sections 28.1 and 28.2 of the Species at Risk Act. The emergency assessment is premised on an application supporting biological information indicating that there is an imminent threat to the survival of the species, and what appears to be a dramatic decline in the numbers of mature fish returning to spawn. Results of the emergency assessment of Steelhead Trout (Thompson River and Chilcotin River Designatable Units) were made public on February 13, 2018, and are available on the Species at Risk Public Registry. This species is under consideration for listing under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, will be made available on the Species at Risk Public Registry as it becomes available. [Updated 2018-02-16]
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.
8 record(s) found.
- COSEWIC Status Reports (2 record(s) found.)
- Response Statements (2 record(s) found.)
- Orders (1 record(s) found.)
- COSEWIC Annual Reports (2 record(s) found.)
- Consultation Documents (1 record(s) found.)
COSEWIC Status Reports
COSEWIC Annual Reports
COSEWIC Annual Report 2017 to 2018 (2018-10-15)Over the past year COSEWIC assessed a total of 90 wildlife species and 11 of these were assigned a status of Not at Risk. Of these 90, COSEWIC re-examined the status of 38 wildlife species; of these, the majority (87%) were reassessed at the same or lower level of risk. To date and with the submission of this report, COSEWIC’s assessments now include 771 wildlife species in various risk categories including 338 Endangered, 183 Threatened, 228 Special Concern, and 22 Extirpated (i.e. no longer found in the wild in Canada). In addition, 18 wildlife species have been assessed as Extinct, and a total of 59 wildlife species have also been designated as Data Deficient and 197 have been assessed and assigned Not at Risk status.
COSEWIC Annual Report 2020 to 2021 (2021-10-12)Over the past year COSEWIC assessed a total of 66 wildlife species, of which 4 were assigned a status of Not at Risk. Of these 66, COSEWIC re-examined the status of 41 wildlife species; of these, 80% were reassessed at the same or lower level of risk. To date and with the submission of this report, COSEWIC’s assessments now include 826 wildlife species in various risk categories including 369 Endangered, 196 Threatened, 239 Special Concern, and 22 Extirpated (i.e. no longer found in the wild in Canada). In addition, 19 wildlife species have been assessed as Extinct, 62 wildlife species have been designated as Data Deficient, and 202 have been assessed as Not at Risk.