Sturgeon

Physical Characteristics

Sturgeons are ancient, prehistoric-looking fish, known for their massive size, bony armor, and distinctive body structure.

Body:
They have an elongated, torpedo-shaped body with a heterocercal tail (upper lobe longer than the lower). Unlike most fish, they lack scales, instead having five rows of tough, bony plates called scutes running along the body.

Head and Snout:
Sturgeons have a long, pointed snout with four sensitive barbels hanging underneath, used to detect prey along river and lake bottoms. Their mouth is toothless, protrusible, and located on the underside of the head, ideal for suction feeding.

Coloration:
Their coloration is generally gray, brown, or olive on top, fading to lighter shades on the sides and white on the belly. This countershading provides camouflage in murky waters.

Fins:
They possess a single dorsal fin set far back on the body, large pectoral fins for maneuvering, and a powerful, shark-like tail for propulsion.

Size:
Sturgeons are among the largest freshwater fish in the world. Depending on the species, they can range from 3–7 ft (1–2 m), while giants like the beluga sturgeon can reach over 20 ft (6 m).

Weight:
Smaller species may weigh 50–200 lbs (23–91 kg), while the largest beluga sturgeons can exceed 1,000 lbs (450 kg).

The sturgeon’s armored body, long snout, and immense size make it one of the most distinctive and ancient-looking fish still alive today.

Reproduction

Sturgeons have slow and infrequent reproductive cycles, which makes them especially vulnerable to overfishing and habitat loss.

Mating and Courtship:
Spawning occurs in spring or early summer, when adults migrate from large rivers, lakes, or coastal areas to upstream gravel beds with strong currents. Courtship involves males nudging and circling females before spawning begins.

Spawning:
Sturgeons are broadcast spawners. Females release hundreds of thousands to several million eggs into the water, while multiple males release milt (sperm) for external fertilization.

Eggs and Development:
The eggs are sticky, adhering to rocks and gravel for protection. They hatch within 5–8 days, depending on water temperature.

Larval Stage:
Larvae, called fry, are initially planktonic and drift downstream, feeding on microscopic organisms. As they grow, they settle into sandy or muddy bottoms.

Maturity:
Sturgeons take a long time to reach sexual maturity—anywhere from 8–20 years, depending on the species. Females reproduce only once every 3–10 years, while males may spawn slightly more often.

The sturgeon’s long maturation period, high egg production, and infrequent spawning cycles make them unique among freshwater fish but also highly susceptible to population decline when disrupted.

Lifespan

Sturgeons are among the longest-lived fish species, with lifespans that rival some of the oldest vertebrates on Earth.

Lifespan in the Wild:
Most sturgeon species live 50–60 years, though some, like the beluga sturgeon, can surpass 100 years. The lake sturgeon of North America commonly reaches 80–100 years, with documented individuals exceeding a century.

Lifespan in Captivity:
In aquaculture and controlled environments, sturgeons can also live several decades, though lifespans are often shorter than in the wild due to space limitations and stress.

Threats to Longevity:
Overfishing for meat and caviar, habitat destruction, and pollution greatly reduce survival rates in the wild. Because sturgeons grow slowly, mature late, and live long, populations are extremely slow to recover once depleted.

The sturgeon’s extraordinary ability to live for over a century underscores its status as a living relic of ancient waters and highlights the urgent need for conservation.

Eating Habits

Sturgeons are benthic (bottom-feeding) fish with specialized feeding adaptations that allow them to thrive in rivers, lakes, and coastal waters.

Diet:
Their diet consists mainly of insect larvae, worms, crustaceans, mollusks, and small fish. Juveniles focus more on insects and tiny invertebrates, while adults incorporate larger prey.

Feeding Behavior:
Sturgeons have no teeth. Instead, they use their four sensitive barbels to detect prey along the substrate. Once located, they extend their protrusible, vacuum-like mouth to suck up food from the bottom.

Foraging Strategy:
They typically feed by stirring up sediment with their snouts, uncovering hidden invertebrates or fish. Their diet adapts to available food sources, making them opportunistic feeders.

Role in the Ecosystem:
As bottom-feeders, sturgeons help recycle nutrients in aquatic ecosystems, contributing to the balance of river and lake environments.

The sturgeon’s reliance on tactile barbels, suction feeding, and benthic foraging sets it apart as a unique and efficient bottom-dwelling predator.

Uniqueness

Sturgeons are remarkable “living fossils,” combining ancient traits with exceptional biological characteristics.

Prehistoric Lineage:
They have existed for over 200 million years, surviving since the time of the dinosaurs with little change in body design.

Immense Size:
Some species, like the beluga sturgeon, are among the largest freshwater fish in the world, capable of reaching over 20 ft (6 m) and 1,000 lbs (450 kg).

Longevity:
With lifespans often exceeding 100 years, sturgeons are among the longest-lived vertebrates on Earth.

Reproductive Uniqueness:
Females produce millions of eggs but spawn only once every several years, making them slow to recover from population declines. Their roe is harvested as caviar, one of the most prized delicacies globally.

Ecological Role:
As bottom-feeders, they play a crucial role in nutrient cycling, while their presence indicates healthy aquatic systems.

The sturgeon’s combination of prehistoric origins, extraordinary size, long life, and economic and ecological importance makes it one of the most unique fish species in the world.