Lake Sturgeon (Saskatchewan River)

Acipenser fulvescens

SARA Status
No Status
NS
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

SARA Status

  • No Status NS
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX
COSEWIC Status
Not at Risk
NR
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

COSEWIC Status

  • Not at Risk NR
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX

General Description

Lake Sturgeon are a slow-growing and long-lived freshwater fish. Although Lake Sturgeon have been recorded to reach over three metres (m) in length and 180 kilograms (kg) in weight, they are now rarely found over 1.5 m in length or 35 kg in weight. The Lake Sturgeon has a cartilaginous skeleton, and a shark-like tail. Rather than fish scales, the juveniles and larval Lake Sturgeon have external bony scutes, which are less pronounced on larger individuals. The head has a pointed snout with four pendulous barbels, and a ventrally located mouth. It is dark to light brown in colour on its’ back and sides, with a lighter coloured belly. Individual Lake Sturgeon have been known to live up to 150 years old, but such ages are rare today. Lake Sturgeon often move short distances (one to 20 km) between feeding sites in large rivers and lakes and into spawning and overwintering areas, but are able to migrate longer distances (greater than 100 km). Unlike most fish, Lake Sturgeon do not sexually mature and begin spawning until they are relatively old, approximately 15 years for males, and 25 years for females. There is also some evidence to suggest that spawning may not take place every year during the reproductive years.

Habitat

The range of Lake Sturgeon once extended from western Alberta to the St. Lawrence drainage in Quebec, and from southern Hudson Bay drainages to the lower Mississippi drainage. Their abundance and historic range in the United States are much reduced and they are considered endangered in many states. In Canada, Lake Sturgeon occur in rivers around southern Hudson Bay, in the Great Lakes, and in inland lakes and rivers from Alberta to Quebec. Lake Sturgeon populations in different areas of Canada are being assessed separately (see Table 1). The Saskatchewan River populations, termed Designatable Unit 2 (DU2), refer to the Lake Sturgeon in the Saskatchewan River system of Manitoba and Saskatchewan and the North and South Saskatchewan River system in Saskatchewan and Alberta.

Lake Sturgeon are bottom-dwelling fish found in large rivers and lakes, at depths generally between 5 and 10 m, sometimes greater. Spawning occurs in the spring in fast-flowing water at depths between 0.6 and 5 m over hard-pan clay, sand, gravel and boulders. Unlike most fish, Lake Sturgeon do not mature and reproduce until they are quite old, typically 15 years for males and 25 years for females. There is also some evidence to suggest that spawning may not take place every year during the reproductive years. The number of eggs may range from 50,000 to over 1,000,000 depending on the size of the fish, and incubation takes about seven to ten days in water of 13 to 15º Celsius. Larvae are negatively buoyant until the swim bladder starts to form about 6o days after hatching. The young-of-the-year grow rapidly and may reach 20 cm by the end of the first summer.

Lake Sturgeon feed on a variety of benthic organisms depending on the season, location and river bottom type. Some food items include small benthic fishes, insect larvae, molluscs, crayfishes, and on occasion, fish eggs. They may also feed in the water column on pelagic zooplankton, such as Daphnia and occasionally on insects at the surface.

Threats

Human activities represent the most important threat to Lake Sturgeon. Historically, commercial fishing caused precipitous declines in many Lake Sturgeon populations. None of these populations has fully recovered. More recently, the direct and indirect effects of dams pose important threats. Dams result in habitat loss and fragmentation, altered flow regimes, and may increase mortality by entrainment in turbines. Habitat degradation resulting from poor land use and agricultural practices also has had an adverse impact on many populations. Other threats may include contaminants, poaching and the introduction of non-native species.

Further Information

To learn more about Lake Sturgeon, visit the Species at Risk (SARA) Public Registry Profile.

Text Sources: COSEWIC Status Report 2006.

Lake Sturgeon (Saskatchewan River)

Lake Sturgeon (Illustration © J.R. Tomelleri)

Acipenser fulvescens
Illustration © J.R. Tomelleri

Scientific Name: Acipenser fulvescens
SARA Status: No Status
COSEWIC Status
: Endangered
Regions: Alberta, Saskatchewan, Manitoba

Distribution of the Lake Sturgeon, Saskatchewan River population in Alberta, Saskatchewan and Manitoba as described in the following paragraphs

The map indicates the distribution of the Lake Sturgeon, Saskatchewan River population in Alberta, Saskatchewan and Manitoba.

Did You Know?

The Lake Sturgeon is one of Canada’s largest freshwater fish and may live to over 100 years.

Lake Sturgeon can be distinguished from the Shovelnose Sturgeon (Scaphirhynchus platorynchus) by its more rounded snout and caudal peduncle.

  • Lake Sturgeon - <em>Acipenser fulvescens</em>

    Photo Credit: U.S. Fish and Wildlife Service

  • Lake Sturgeon - <em>Acipenser fulvescens</em>

    Photo Credit: Karen Scott

  • Lake Sturgeon - <em>Acipenser fulvescens</em>

    Photo Credit: Karen Scott

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