Some species of sturgeon are the largest and most long-lived freshwater fishes. In 1953, a lake sturgeon was caught that was estimated to be 154 years old. The largest is the Russian sturgeon (Huso huso), or beluga. It can reach a length of 8.5 meters and has been known to weigh over 1500 kilograms.
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Perception Channels: tactile ; chemical
Lake sturgeon populations have declined in the last century. This is due partly to overfishing, pollution of rivers, and to some extent because river damming has destroyed spawning runs. (Rodgers 1990)
Lake sturgeon used to be one of the most important fish in the Great Lakes. Heavy fishing and pollution from newly developed land around the lakes has caused it to become very rare. (Evans 1994) Lake sturgeons are listed as threatened by the state of Michigan.
US Federal List: no special status
CITES: appendix ii
State of Michigan List: threatened
IUCN Red List of Threatened Species: least concern
The lake sturgeon does not appear to present any negative attributes concerning the environment or humans.
The lake sturgeon is best known as a food fish. Their unfertilized eggs, carried inside the female, are considered a delicacy. These eggs are the luxury food known as caviar. The meat of this fish is also eaten. Lake sturgeon have been fished for their flesh and their oil as well as for their caviar. Steamboats in North America once used their oil as fuel. They have also supplied isinglass. Isinglass is a form of gelatin and is obtained from the sturgeon's swimbladder and vertebrae. It was traditionally used to clarify wines and as a gelling agent in jams and jellies. Today, it is used for special cements and water-proofing materials, but its main use is in cleaning white wines. (Evans 1994)
The name sturgeon in several European languages means "the stirrer", from the way the fish rummages among the mud for food. It finds its food largely by touch, using its sensitive barbels. As the lake sturgeon cruises over the bottom, the sensitivity of the fleshy whiskers trailing in the sand makes up, to some extent, for the fish's poor eye sight. As soon as the whiskers pass over food, the protrusible mouth drops down with an elevator-like motion and rapidly sucks in its meal. (Herald 1971) Acipenser fulvescens are one of the few fishes to have taste buds on the outside of their mouth. In other fish, they are normally found on the tongue or inside the mouth. The taste buds of the lake sturgeon protrude from the toothless mouth and are used to help in the selection of food.
These fish are slow feeders and can survive several weeks without eating. Moreover, the food it eats is small compared to its own size. The lake sturgeon, in its normal habitat, must devote a great deal of time to feeding. Acipenser fulvescens eat insect larvae, worms, crayfish, snails, and other small fishes. (Rodgers 1990)
Acipenser fulvescens occurs in the freshwaters of North America from the Hudson Bay through the Mississippi River drainages to Alabama. It is found along the Great Lakes - St. Lawrence River drainage and in large lakes in New York and Vermont, including Cayuga Lake and Lake Champlain.
Biogeographic Regions: nearctic (Native )
The lake sturgeon is a fish of temperate waters and is found only in the Northern Hemisphere in North America. Their habitat is usually on the bottom of a riverbed or lake. Acipenser fulvescens prefer a river or lake bottom that has clear sand or gravel. (Herald 1971)
Aquatic Biomes: lakes and ponds; rivers and streams
Average lifespan
Status: wild: 82.0 years.
Average lifespan
Status: wild: 152.0 years.
This fish has a skeleton partly of bone and partly of cartilage. Their slender bodies are covered with rows of bony plates. Beneath the projecting snout there is a small, toothless mouth with thick, sucking lips. There are four barbels (whiskers) in front of the mouth that are used to direct food towards the mouth. Like the body, the head is well protected with plates. A single dorsal fin rises from the back, and the body extends into the long upper part of the tail fin. (World Book Encyclopedia 1998)
The physical characteristics of Acipenser fulvescens vary greatly with age and size. In the young, the body shields are rough and ornamented with hooked spines. As they become adults, the shields grow smoother. Many of them eventually disappear with age. The snout also grows less pointed with age, and the spots of the younger fishes' color pattern disappear. It is common for the lake sturgeon to reach a length of about 1.8 meters and have a mass, on average, of 90 kilograms. (Encyclopedia Americana 1996)
Average mass: 90 kg.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Average mass: 70000 g.
In early summer, lake sturgeons migrate toward the shores of freshwater lakes for spawning purposes. They seek out pebbly habitats with no mud to breed. (Evans 1994) Spawning usually takes place at a depth of 5.4 to 6.0 meters. The females lay a vast number of eggs, anywhere from 2 to 3 million in one season, depending on their size and age. After spawning, the eggs are left to develop on their own. The parents will then return to the lake or river where they spend most of their time. (Rodgers 1990)
The eggs, or roe, are small and sticky. They are encased in a jelly-like substance and use the stickiness to adhere to water plants and stones, or clump together in masses. This allows them to remain stationary and stay in one location despite the current. The eggs are one-fourth of a centimeter in diameter and blackish in color. They will normally hatch in three to seven days. The larvae are 1.25 centimeters long and by the first summer may grow to a length of 20 centimeters. The young grow rapidly until maturity, after which growth continues slowly for several years. (Rodgers 1990)
Although the Russian sturgeon (Acipenser huso) may reach a length of 30 centimeters in one year, the lake sturgeon requires twenty years to attain a length of a little over a meter. Acipenser fulvescens become sexually mature when they are around the age of twenty and at a length of a little over a meter. (Herald 1971)
Average gestation period: 6 days.
Average number of offspring: 350000.
Average age at sexual or reproductive maturity (male)
Sex: male: 2920 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 9490 days.
