Lake Sturgeon Saskatchewan - Nelson River populations
Scientific Name: Acipenser fulvescens
Taxonomy Group: Fishes
COSEWIC Range: Alberta, Saskatchewan, Manitoba, Ontario
COSEWIC Assessment Date and Status Change: April 2017
COSEWIC Status: Endangered
COSEWIC Status Criteria: A2bc
COSEWIC Reason for Designation: This is one of the largest, longest-lived, freshwater fish species in Canada and has special significance to Indigenous Peoples. Formerly assessed as five separate designatable units, recent genetic evidence indicates that those populations should be treated as a single unit. Harvesting and dams were the main reasons for historical declines. Although some populations appear to be recovering, this species is not yet clearly secure.
COSEWIC History of Status Designation: The species was considered a single unit and designated Not at Risk in April 1986. When the species was split into separate units in May 2005, the "Western populations" unit was designated Endangered. In November 2006, the Western populations unit was split into five separate populations. In April 2017, the Winnipeg - English River, Red-Assiniboine Rivers - Lake Winnipeg, Saskatchewan River, Nelson River, and Lake of the Woods - Rainy River populations were considered a single unit and this 'Saskatchewan - Nelson River populations' unit was designated Endangered.
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.
The Lake Sturgeon is one of five sturgeon species found in Canada. It is one of Canada’s largest freshwater fishes. Lake Sturgeon has a pointed snout, ventral protrusible mouth, four barbels in front of the mouth, five rows of bony scutes, and a heterocercal tail. The Lake Sturgeon has a rich historical significance to First Nations peoples and was also commercially harvested across much of the species’ range between the late-1800s and mid-1900s. The St. Lawrence River in Quebec supports the only remaining commercial fishery. Aboriginal fisheries are ongoing. Caviar, made from Lake Sturgeon eggs, is still highly prized. Lake Sturgeon is also sought by trophy anglers (where permitted; predominantly catch-and-release) in many locations. [Updated 2018-02-19]
Distribution and Population
The Canadian range stretches from the North and South Saskatchewan rivers in Alberta in the west, to the St. Lawrence River estuary in the east, and from various rivers that empty into Hudson Bay in the north to several boundary waters (e.g., Rainy River, Great Lakes) in the south. The majority of Lake Sturgeon populations in Canada declined precipitously over a period of ~150 years beginning in the 18th century. Some of the well-studied populations appear to be rebounding, with several populations consisting of tens of thousands of individuals and others likely approaching carrying capacity. Still, a sizable proportion of populations have yet to exhibit meaningful signs of population recovery, and the species has disappeared from some formerly inhabited areas. [Updated 2018-02-19]
The range of the Lake Sturgeon spans four freshwater biogeographic zones and six terrestrial ecozones. The species occupies a wide variety of aquatic ecosystem types (e.g., stepped-gradient Boreal Shield rivers, low-gradient meandering Prairie rivers, low gradient Hudson lowland rivers, Great Lakes and associated tributaries). Habitat Requirements Lake Sturgeon requires a variety of habitats to complete its lifecycle, and the species has evolved to exploit typical upstream to downstream hydraulic and substrate gradients. Spawning habitat is typically characterized by fast-moving water found at the base of falls, rapids, or dams. Hatch is contingent on aeration by flowing water, after which larvae apparently require gravel substrate in which to bury and remain while development continues. Once the yolk sac is absorbed, larvae drift downstream via water currents. Habitat requirements at the age-0 stage are not well understood, but may not be as strict as previously assumed. Aside from the requirement of adequate benthic prey items, the habitat requirements for middle to later life stages (juveniles and adults) are not particularly narrow. Habitat Trends Habitat trends vary across the species’ range. In some areas, the construction of dams has ceased but, in other areas, it is expected to continue into the foreseeable future. Sediment and water quality has improved in many areas formerly impacted by pollution from the pulp-and-paper industry. [Updated 2018-02-19]
General The Lake Sturgeon is a benthic generalist, whose forage base diversifies as body size increases. Reproduction Spawning occurs during spring and has been observed at water temperatures ranging from 8-21.5°C. Females are attended to by multiple males, and males may spawn with multiple females during a given year. Eggs are broadcast into the water column, and those fertilized develop a sticky exterior and adhere to the substrate. Age at maturity for males is generally in the range of 12-20 years, and 15-30 years for females. Males generally spawn every 1-3 years, and females every 2-7 years. Recruitment Inter-annual recruitment across the species’ range is often variable or erratic, apparently influenced by biological, environmental, and anthropogenic factors. Survival There is low survival to age-1. Once age-1 has been reached, annual survival may be very high, barring anthropogenic influences. Physiology Maximum thermal tolerance of Lake Sturgeon is believed to be in the range of 28- 30°C.In terms of cold tolerance, the species can survive temperatures of 0°C for up to 6 months. Lake Sturgeon occupies rivers characterized by a wide range of turbidity, clarity, and oxygen levels. Lake Sturgeon is known to move into estuarine environments, but the species has a low salinity tolerance. Movements/Dispersal Movement patterns of Lake Sturgeon are driven by the physical separation of habitats needed to complete life-history processes. In low-gradient systems, the species may need to migrate hundreds of kilometres between spawning, foraging, and overwintering habitats. In stepped-gradient systems, habitat diversity can occur over small spatial scales and recruiting populations are known to occur in hydroelectric reservoirs as small as 10 km in length. Furthermore, genetic results indicate populations historically occurred in small, naturally fragmented sections of several large stepped-gradient riverine systems for thousands of years. Dispersal is limited to connected wetted habitats, with volitional movement (primarily by adults) and passive downstream redistribution of larvae being the primary natural processes that influence inter-population dynamics. [Updated 2018-02-19]
Threats to sustainability and/or impediments to recovery of Lake Sturgeon populations include harvest, habitat alterations (primarily due to dams), barriers to migration (dams), entrainment losses (dams), invasive species, and pollution. [Updated 2018-02-19]
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.
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
COSEWIC Annual Report 2016 to 2017 (2017-10-24)Over the past year COSEWIC re-examined the status of 40 wildlife species; of these, the majority (78 %) were reassessed at the same or lower level of risk. Of a total of 73 species assessed 11 were assigned the status of Not at Risk (8 re-assessments and 3 new assessments). To date and with the submission of this report, COSEWIC’s assessments now include 735 wildlife species in various risk categories including 321 Endangered, 172 Threatened, 219 Special Concern and 23 Extirpated (i.e. - no longer found in the wild in Canada). In addition 16 species have been assessed as Extinct, 58 have been designated as Data Deficient and 186 were assessed and assigned Not at Risk status.