Acipenser

Sturgeon2

Acipenser is a genus of fishes known commonly as sturgeons, belonging to the family Acipenseridae. Sturgeons are among the oldest living species of fish, with fossils dating back to the Cretaceous period. They are native to temperate waters of the Northern Hemisphere, including North America, Europe, and Asia. Acipenser species are known for their elongated bodies, scaleless skin, and heterocercal tail, which means the upper lobe of the tail is longer than the lower lobe. They also have a distinctive series of bony plates, or scutes, along their sides and back.

Description

Sturgeons are large, slow-growing fish that can live for several decades; some species can live for over 100 years. They vary in size from relatively small species that reach about 2 feet in length to giants such as the Beluga sturgeon (Acipenser huso), which can grow to over 20 feet in length and weigh over 2,000 pounds. Their diet primarily consists of small fish, crustaceans, and insects.

Habitat and Distribution

Acipenser species are found in a variety of freshwater and brackish water habitats. They are anadromous, meaning they migrate up rivers from the sea to spawn. However, some populations are known to live entirely in freshwater. Their habitats range from large rivers and lakes to coastal waters.

Conservation Status

Many species of Acipenser are considered to be at risk of extinction due to overfishing, habitat loss, and pollution. The demand for their roe, which is processed into caviar, has led to intense fishing pressure. As a result, international trade in sturgeon products is regulated under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

Reproduction

Sturgeons are known for their late maturity and long lifespan, which contribute to their vulnerability to overfishing. Females of some species do not reach reproductive age until they are 15 to 20 years old. They lay a large number of eggs, which are fertilized externally. The survival rate of sturgeon eggs and larvae is low, however, which contributes to the difficulty in replenishing populations.

Economic Importance

In addition to caviar, sturgeons are valued for their flesh, which is considered a delicacy in many cultures. They are also fished for sport. Conservation efforts include farming sturgeons for caviar production to reduce pressure on wild populations.

Species

The genus Acipenser includes several species, such as the Beluga sturgeon (Acipenser huso), Siberian sturgeon (Acipenser baerii), and Atlantic sturgeon (Acipenser oxyrinchus). Each species has its own range and habitat preferences, but all share common features that define the genus.

See Also

• Fisheries management
• Endangered species
• Aquaculture