Lake sturgeon

Description

Size

• The largest freshwater fish in the Northern Hemisphere belong to the sturgeon family.
• The biggest sturgeon reported in Alberta weighed 48 kilograms (105 pounds) and was 155 centimetres (61 inches) in length.

Appearance

• A living "dinosaur" of the fish world, this unusual species is torpedo-shaped and armor-plated.
• Instead of scales, the sturgeon's large brown or grey body is covered with tough, leather-like tissue and five rows of bony plates.
• It has a shark-like, upturned tail and a pointed snout with four barbels, whisker-like tissue filaments.

Distribution

• Lake Sturgeon range in the North and South Saskatchewan river systems.

Natural History

Habitat

• Despite the name, lake sturgeon are strictly river fish in Alberta.

Food

• Sturgeon are mostly bottom feeders. Their varied diet includes tiny organisms such as:
  • clams
  • insect larvae
  • plant material
  • some fish and fish eggs

Reproduction and Growth

Breeding Behaviour

• Spawning takes place in late spring, every five years or so.
• 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.
• 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 do not spawn until they are about 15 to 20 years old. Females usually spawn between the ages of 20 and 25.
• Lake sturgeon can live up to 100 years, the longest life span of Alberta's cool-water fishes.

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; protective regulations under this act that apply to fish species are under development. See:

• Species at Risk

This species is also protected under the Alberta Fisheries Regulations, which regulate fisheries harvest in Alberta.

Issues

• Populations are at or below critical levels for sustainability.
• Threats include habitat degradation and fragmentation.
• Inherent biological characteristics make recovery difficult.

Current management

Fish Sustainability Index

Alberta's lake sturgeon populations have been assessed under the Fish Sustainability Index, see:

• Lake Sturgeon FSI

Fishing

Lake sturgeon are cool-water game fish subject to current Alberta sportfishing regulations. For details, see the My Wild Alberta website at:

• Fishing

Sturgeon fishing is strictly catch and release to preserve this unusual and interesting species. For an explanation of current management strategies, see:

• Fish - Lake Sturgeon

Lake sturgeon monitoring in the North Saskatchewan River was recently profiled in an episode of Hidden Gems on the Alberta Prime Time website. See:

• Taking Stock of Threatened Lake Sturgeon in Alberta