Lake Sturgeon

Acipenser fulvescens

Historically, sturgeon were abundant prior to European settlement and in the mid to late 1800’s, it was among the 5 most abundant fish in commercial catch. The decline was rapid and the sturgeon was extirpated from some of the tributaries and water where they had spawned.

Species at Risk Status

Federal Government status: Threatened

Provincial Government status: Endangered

Have you seen this species at risk? Report your sighting.

Description

Often referred to as a living fossil, sturgeon date back to the Upper Cretaceous Period – 65 to 100 million years ago when dinosaurs still roamed the earth! It is Canada’s largest freshwater fish: recorded in excess of 2 m in length and 136 kg in weight, although most sturgeon today are much smaller; average weight 4.5 kg – 36 kg (10 – 80 lb); average length .9 – 1.5 m (3 – 5 ft).
Unlike most fish, they don’t have scales. There are 5 rows of thick armour like platelets along the back and sides; the skin is covered with tiny tooth like projections that give it the feel of fine sandpaper.
The fins are dark brown or grey with the single, dorsal fin far back near the caudal fin.
Belly is white or light-coloured and contrasts with the darker back and sides; overall, colour is uniform in adults, younger fish may appear blotchy.
Vertebrae consist of cartilage not bones.

Food

Feeds on insect larvae, crayfish, molluscs, small fish and occasionally plants.

Habits and Reproduction

Specialized bottom feeder: a large, toothless suctorial mouth is well back of the snout on the underside of the head. There are 4 barbels (whisker like appendages) in front of the mouth, which are used for sensing its surroundings and food.
Females reach maturity between 14 and 33 years, most often from 24-26 years; and 8 to 12 years for males (but may take up to 22 years).
Female lake sturgeon spawn once every 4 to 9 years while males spawn every 2 to 7 years; spawning occurs on clean, gravel shoals and stream rapids from April to June.
Individuals usually return to the same spawning rivers year after year.
Females lay 4,000 to 7,000 eggs per pound of fish
Typical lifespan of a lake sturgeon is 55 years for males and 80-150 years for females.

Habitat

Large rivers and lakes.
Known spawning areas include the Pickerel and Moon Rivers. Any of the large river mouths emptying into Georgian Bay could be potential or existing spawning sites. This could include: Severn, Musquash, Go Home, Seguin, Shawanaga, Naiscoot and Magnetawan Rivers.

Threats

Barriers (dams) in tributaries that prevent spawning.
Reduced water quality.
Predation on eggs and fry.
Lake sturgeon are highly vulnerable to commercial fishing gear (gill nets) and at one time were considered a nuisance and coarse fish. The exceptionally long period it takes for them to mature makes them vulnerable to harvest well before they have an opportunity to reproduce. This scenario has contributed significantly to decimation of the species.

Conservation Actions

Please report any sightings of lake sturgeon to the address below.