Scientific Name: Acipenser medirostris
Taxonomy Group: Fishes
Range: British Columbia, Pacific Ocean
Last COSEWIC Assessment: November 2013
Last COSEWIC Designation: Special Concern
SARA Status: Schedule 1, Special Concern
Image of Green Sturgeon
The Green Sturgeon has a rounded body, small eyes, a sharp snout and a toothless ventral mouth with sensory barbels. The dorsal fin and pelvic fins are located towards the caudal fin (tail), which is broadly pointed. The pectoral fins are large and rounded. The body and upper part of the head are coloured dark green to olive green, while the lower part of the head is a paler green. The ventral surface is white, with a dark olive-green stripe extending down the middle of the belly, often terminating behind the pectoral fins. The pectoral fins are dusky grey to pale green. Sturgeons differ from other bony fish in that they have a cartilaginous skeleton instead of bone, and large bony plates (scutes) instead of scales. The Green Sturgeon likely lives to 60-to-70 years old, and has a maximum length of 2.1 meters and maximum weight of 159 kilograms. Males generally mature at 15 years of age, while females mature at 17 years. Green Sturgeon is anadromous, meaning it returns to freshwater to reproduce. Spawning is believed to occur every two to five years, with females producing between 60,000 and 140,000 eggs. Juveniles stay in rivers and estuaries for several years before dispersing widely into the marine environment. In North America, the range of the Green Sturgeon overlaps with that of the White Sturgeon which is generally similar in appearance, but varies in size. An adult White Sturgeon has a maximum length of 6.1 meters and maximum weight of 816 kilograms, substantially larger than its Green Sturgeon counterpart.
Distribution and Population
Green Sturgeon are found along the western coast of North America, from Mexico to southeastern Alaska. The Canadian distribution of Green Sturgeon includes the entire coast of British Columbia, as it is part of the northward oceanic migration pattern for the species along the Pacific coast of North America. There is very little information on the size of the Canadian Green Sturgeon population, and its population trends are not known.
Green Sturgeon are found along the western coast of North America, from Mexico to southeastern Alaska. The Canadian distribution of Green Sturgeon includes the entire coast of British Columbia, as it is part of the northward oceanic migration pattern for the species along the Pacific coast of North America. There is very little information on the size of Canada’s Green Sturgeon population, and population trends are unknown. Green Sturgeon are usually found in saltwater, but occupies freshwater during the spawning season. Spawning occurs primarily in three rivers in the United States. Green Sturgeon is rarely encountered in fresh water in Canada, but will inhabit the brackish waters found at the mouth of large rivers; adult and subadult Green Sturgeon aggregate in non-natal estuaries in coastal bays for periods of up to several months during the marine phase of their life cycle. The reason for this aggregation is unclear, although it has been suggested that feeding does not occur during this time, and that aggregation is related instead to physiological requirements with respect to temperature. Recent research has identified large concentrations of Green Sturgeon near Brooks Peninsula on northwest Vancouver Island during May through June and October through November, suggesting that important overwintering habitat might exist north of Vancouver Island and south of Cape Spencer, Alaska.
There is little information on the general biology of the Green Sturgeon. Green Sturgeon are anadramous but spend the majority of their time in the marine environment. They are long-lived species, having been recorded to reach an age of 42 years, although it is possible that Green Sturgeon can reach ages of 60-70 years. Although spawning is not known to occur in Canadian waters, it is known that mature adults migrate up rivers to spawn from March to July. Juveniles migrate downstream as they grow, and move into estuaries within the first year and a half of life where they reside for one to two years. Migration to marine waters occurs between 2.5 to 3.5 years. Males spend three to nine years while females spend three to fifteen years at sea before returning to freshwater to spawn. Green Sturgeon reach sexual maturity at 14 to 20 years, and reproduce every to two to five years. Females can produce 60,000 to 140,000 large eggs, reaching maximum fecundity at 24 years.
Although there are currently no directed commercial and recreational fisheries for this species, Green Sturgeon is occasionally caught incidentally in commercial groundfish trawl fisheries, commercial and First Nations salmon gillnet and beach seine fisheries, as well as recreational fisheries. Additionally, habitat loss can have impacts to Green Sturgeon, although the severity of the impact on these populations is unknown. Green Sturgeon is also at risk of exposure to Persistent Bioaccumulative Toxins (PBTs) during their freshwater and estuarine phases, and the species is vulnerable to chronic and acute effects of bioaccumulation due to its long lifespan. Although contaminant levels have not been measured in Green Sturgeon, White Sturgeon has been shown to carry high contaminant loads. Overall, the threat of accidental mortality through fisheries bycatch is higher than the threats of habitat destruction and pollution; however, this threat is likely of lower risk in Canada. The main threats to Green Sturgeon are likely higher in the US portion of its range where known Green Sturgeon spawning and rearing habitats are located. These threats include freshwater habitat impacts from dams, dikes and other industrial activities that can affect the availability and suitability of habitats for successful reproduction and rearing.
Federal ProtectionMore information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
A SARA Management Plan for Green Sturgeon in Canada is currently being developed. The management plan highlights the management objectives and strategies for maintaining sustainable population levels of the species. Additionally, under the Fisheries Act’s BC Sport Fishing Regulations, it is illegal to retain any Green Sturgeon caught while sport fishing in Canada.
Provincial and Territorial Protection
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.
14 record(s) found.
- COSEWIC Status Reports (1 record(s) found.)
- COSEWIC Assessments (2 record(s) found.)
- Response Statements (2 record(s) found.)
- Action Plans (1 record(s) found.)
- Management Plans (1 record(s) found.)
- Orders (2 record(s) found.)
- COSEWIC Annual Reports (2 record(s) found.)
- Consultation Documents (2 record(s) found.)
- Recovery Document Posting Plans (1 record(s) found.)
COSEWIC Status Reports
COSEWIC Annual Reports
COSEWIC Annual Report - 2005 (2005)2005 Annual Report to the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
Recovery Document Posting Plans
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