Common, or Baltic, sturgeon
The Common, or Baltic, sturgeon (Acipenser sturio) is a critically endangered species found primarily in the coastal waters of Europe. This large fish is notable for its ability to inhabit both fresh and saltwater environments, making it the only anadromous sturgeon in Europe. Common sturgeons have a distinctive rounded body covered in bony plates called scutes, and they can grow up to eleven feet in length and weigh as much as 600 pounds. They primarily feed on invertebrates and small fish, using sensitive feelers called barbels to detect food along the seafloor.
Historically abundant, the population of the Common sturgeon has significantly declined due to over-harvesting for caviar. Other threats include fishing, pollution, and habitat disruptions from dams, which impede their spawning migrations. Spawning typically occurs between May and June, during which females can lay millions of eggs. Despite their resilience, with lifespans exceeding 100 years, the survival of this species is increasingly at risk, highlighting the urgent need for conservation efforts to protect their habitats and populations.
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Common, or Baltic, sturgeon
The common, or Baltic, sturgeon is a species of fish that is also known as the European sea sturgeon. As its name implies, it is mostly found in coastal habitats of Europe. The common sturgeon is a source of some of the world's finest caviar. The over-harvesting of the sturgeon's unfertalized eggs has greatly diminished numbers. The common sturgeon is listed as a critically endangered species.
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Acipenseriformes
Family: Acipenseridae
Genus: Acipenser
Species: Sturio
The common sturgeon is a large fish which can swim in both fresh and saltwater. It is the only sturgeon species in Europe that has this ability. Fish that can swim in both fresh and saltwater are called anadromous. The common sturgeon spends most of its time feeding near the bottom of inshore waters where the depth ranges between fifty and 150 feet (fifteen to forty-five meters) deep. Common sturgeons can typically be found along the bottom of the sea or in an estuary where the water is brackish as it digs in the mud and sand with its pointed snout. Four sensitive feelers called barbels hang from its chin and help it find invertebrates, like mollusks, worms, and shrimp. It may also prey upon small fish like sand eels and gobies. The mouth extends forward like a tube to suck in any food the barbels detect.
This sturgeon has a heavy, rounded body with large scutes. Scutes are bony plates which lie in five rows all along its body. A male ranges between three and five feet (one to 1 1/2 meters) long, and a female grows to be four to seven feet (one to two meters) long. Larger fish may even reach eleven feet (between three and 3 1/2 meters) long. Common sturgeons may weigh up to 600 pounds (270 kilograms). A dorsal, or back, fin is located slightly in front of its large, pointed tail. An anal fin grows near the tail, and a pelvic fin lies a little farther forward, both on the body's underside. Located below and just behind the gills are two large pectoral fins.
Each female may produce over two million eggs. A common sturgeon may travel over 600 miles from its feeding range to reach the place where it spawns, or lays, its eggs.
Because of their size and tough scutes, sturgeons face few natural enemies. Sea lampreys are one common threat. These eel-like creatures attach themselves to adult sturgeons and feed on their blood and tissue, which may result in death. Of greater threat to sturgeons are fishing, pollution, dams, and other obstacles that prevent the fish from spawning in rivers and lakes.
Spawning is the time when the sturgeons lay and fertilize their eggs. For the common sturgeon, this occurs in May and June. During this time the fish make spawning runs, or migrate, from their homes to spawning grounds. Some fish may return 600 miles (960 kilometers) to freshwater from the sea. Spawning grounds may be hundreds of miles (hundreds of kilometers) further inland and are usually around twenty feet (six meters) deep. They stop feeding during the time they are running and spawning. A female may produce millions of eggs which the male fertilizes as the eggs settle and stick to vegetation and stones in the water. The eggs hatch three to seven days later. The adults return to their homes after spawning. The fry, or young fish, swim to the sea after three years. After five years of growth, sturgeon fry are around twenty inches (fifty centimeters) long. Males are fully-grown after seven to nine years, and females are able to spawn for the first time when they are between eight and fourteen years old.
Once abundant in Europe, the common sturgeon's population numbers have greatly diminished. All eighteen species are threatened. This status can mainly be attributed to over-harvesting for its caviar.
The life span of a common sturgeon may be 100 years or more.
Similar species:
- Atlantic sturgeon(Acipenser oxyrinchus)
- Siberian sturgeon (Acipenser baerii)
- Shortnose sturgeon (Acipenser breviorstrum)
- Sakhalin sturgeon (Acipenser mikadoi)
- Adriatic sturgeon (Acipenser naccarii)
Bibliography
“Acipenser sturio European Sturgeon.” Animal Diversity Web, 2024, animaldiversity.org/accounts/Acipenser‗sturio/classification. Accessed 9 Apr. 2024.
“European Sea Sturgeon.” Animalia, 2024, animalia.bio/european-sea-sturgeon. Accessed 9 Apr. 2024.
“European Sea Sturgeon Acipenser sturio.” iNaturalist, www.inaturalist.org/taxa/93193-Acipenser-sturio. Accessed 9 Apr. 2024.