Lake sturgeon

Description

Size

• As the largest fish in Alberta, lake sturgeon can grow to be up to 10 feet long.

• A living ‘dinosaur’ of the fish world, this unusual species is torpedo-shaped and armor-plated.
• Like other prehistoric fish, sturgeon do not have scales – they have denticles. Denticles are scale-like plates found along the skin of the sturgeon, which give the skin its roughness. They also have 5 rows of bony plates, called scutes.
• It has a shark-like, upturned tail and a pointed snout with 4 barbels, whisker-like tissue filaments.

Distribution

• Despite the name, lake sturgeon are strictly river fish in Alberta; living in the North and South Saskatchewan river systems.

Natural history

Habitat

• The usual habitat where lake sturgeon can be found are along highly productive shoals, which are ridges, banks or bars under water.
• With adequate bottom-dwelling prey, lake sturgeon can live in a variety of habitats.
• Spawning habitat is typically characterized by fast-moving water.

Food

• Sturgeon are bottom feeders, eating clams, insect larvae and some fish and fish eggs.

Reproduction and growth

Breeding behaviour

• Spawning takes place in late spring in water temperatures from 8°C to 21°C; males spawn every 1 to 3 years and females every 2 to 7 years.
• Females do not build a nest, but deposit their eggs in the river current. Males swim close to the females during egg laying to fertilize the eggs.
• Fertilized eggs develop a sticky coating and attach to the river bottom.
• Large females can produce up to 500,000 eggs.

Growth process

• Lake sturgeon take a longer time to reach maturity than other Alberta fish species.
• Male sturgeon start spawning at 15 to 20 years old. Females start spawning later, between the ages of 20 and 25.
• Lake sturgeon can live up to 150 years, with the oldest fish in Alberta being recorded at 62 years old.

Conservation and management

Status

Lake sturgeon are classified as At Risk in the current General Status of Alberta Wild Species report. See:

• General status of Alberta wild species

Sturgeon are also classified as Threatened under Alberta's Wildlife Act. See:

• Species at Risk

This species is also protected under the Alberta Fisheries Regulations, which regulates sportfishing in Alberta.

Issues

Threats include:

• habitat degradation due to water pollution and fragmentation due to dams
• improper handling during angling
• changing climate leading to reduced flow during summer months and increased water temperatures
• introduction of invasive or stocked species
• inherent biological characteristics (for example, slow growth and age to maturity) make recovery a long-term initiative

A full list of issues and threats can be found on the Lake Sturgeon FSI web page.

Current management

Lake sturgeon population assessments are ongoing. On completion, these population assessments will update the provincial lake sturgeon population status. This work will be done through a collaborative mark-recapture angling program with the Alberta government and citizen scientists. Lake sturgeon captured are checked for a tag, and if none is detected, they will be tagged. Based on the ratio of tagged to untagged fish, fisheries biologists can estimate the number of lake sturgeon in the river.

Alberta biologists collaborate with the provincial government of Saskatchewan, the Department of Fisheries and Oceans Canada and other researchers to complete a standardized and unified assessment of lake sturgeon abundance and distribution. Lake sturgeon tissues are also be collected and analyzed for diseases and genetic considerations.

Fish Sustainability Index

Alberta's lake sturgeon populations have been assessed under the Fish Sustainability Index. For the most recent assessment, see:

• Lake Sturgeon FSI

Fishing

Lake sturgeon are catch and release only, as listed in the Alberta sportfishing regulations. For handling tips, see the My Wild Alberta website at:

• Sturgeon handling practices

For an explanation of current management strategies, see:

• Fish – Lake Sturgeon