Lake sturgeon
Acipenser fulvescens
FAMILY
Acipenseridae
TAXONOMY
Acipenser fulvescens Rafinesque, 1917, Lake Erie, North America.
OTHER COMMON NAMES
English: Freshwater sturgeon, Great Lakes sturgeon; French: Esturgeon jaune; Spanish: Esturión lacustre.
PHYSICAL CHARACTERISTICS
The back and sides of large lake sturgeon are olive-brown to dull gray in color; juveniles are light brown with dark blotches. Most lake sturgeons today are 3–5 ft (0.9–1.5 m) long and weigh 10–80 lb (4.5–36.3 kg), but a female of nearly 8 ft (2.4 m) and 310 lb (140.6 kg) has been documented.
DISTRIBUTION
Lake sturgeons occur in the following North American drainages: Great Lakes, St. Lawrence River, Hudson Bay, and Mississippi River.
HABITAT
Lake sturgeons inhabit large rivers and lakes.
BEHAVIOR
Lake sturgeons migrate seasonally between shallow and deeper waters, particularly in the northern extent of their range. They also undertake extensive migrations, typically of around 80 mi (128.7 km), to find suitable spawning grounds in rivers.
FEEDING ECOLOGY AND DIET
Lake sturgeons primarily consume insects, as well as other benthic invertebrates, such as snails, clams, and crayfishes. They occasionally feed on fish eggs, algae, and small fishes.
REPRODUCTIVE BIOLOGY
Lake sturgeons first spawn at 14–23 years for females and 12–20 years for males. Spawning intervals range from two to seven years in males and four to nine years in females. In the spring when ice clears, lake sturgeons migrate into smaller rivers and streams for spawning. Spawning typically takes place in swift-moving water 2–15 ft (0.6–4.6 m) deep. In the Great Lakes, lake sturgeons spawn along rocky shores in groups of two to three individuals. Females shed eggs in batches over a period of days. The eggs adhere to rocks for five to eight days before hatching.
CONSERVATION STATUS
Populations of lake sturgeons are threatened because of human exploitation, as well as habitat alteration and fragmentation that is caused by the construction of dams and roads. Lake sturgeons are listed as Vulnerable by the IUCN. They are protected by state and provincial fishing regulations and habitat restoration efforts in the United States and Canada.
SIGNIFICANCE TO HUMANS
Lake sturgeons were harvested for food by Native Americans before Europeans settled in North America, and commercial markets developed for the eggs and smoked flesh in the mid-1800s. Isinglass, a gelatin obtained from the swim bladder, was used to make jam and jellies, as a pottery cement, and as a waterproofing agent. Recreational fishing for lake sturgeons remains popular.
