European sturgeon - Photo: NOAA Fisheries
European sturgeon - Photo: NOAA Fisheries
About the Species
The European sturgeon is a long-lived, anadromous species. that historically bred in all large rivers in Europe. The last remaining population occurs in the Gironde-Garonne-Dordogne basin in France. The European sturgeon is listed as endangered throughout its range under the Endangered Species Act.
Population Status
The abundance of wild, mature European Sturgeon is considered to be below 800 individuals, though no detailed population estimates are available. The species last spawned in 1994 in the Garonne River, France, and genetic research suggests that the 1994 cohort originated from just one mating pair. As the wild population has such low abundance, a captive breeding and stocking program is critical to the survival of the species. Although restoration activities, including restocking of artificially bred individuals, have been successful in the Gironde estuary and the Elbe River (Germany), recovery is a slow process that may take a minimum of 30-50 years for the European sturgeon. The species currently faces threats of bycatch in commercial trawls and gillnets, pollution, climate change, and potentially competition with introduced sturgeon and predation.
Protected Status
ESA Endangered - Foreign
CITES Appendix I
Appearance
The European sturgeon is a large species that can grow up to 20 feet in length. It has an olive‐black upper body and a white belly. Like all sturgeon, the species has a cartilaginous skeleton, heterocercal caudal fins (upper lobe larger than lower), single spiracle respiratory openings, a bottom-oriented mouth with four barbels (sensory “whiskers”), a flat snout, a strong rounded body, and unique ganoid scales.
Behavior and Diet
The species can tolerate a wide range of salinities and spends most of its life in saltwater (close to the coast), but migrates to spawn in freshwater. They feed on crustaceans, mollusks, and especially worms, and small fishes as juveniles.
Where They Live
The last remaining population of European sturgeon occurs in the Gironde-Garonne-Dordogne basin in France.
Lifespan & Reproduction
Males and females mature at 8-12 years and 13-16 years, respectively. Available studies indicate that males reproduce every other year, while females only reproduce every 3 or 4 years. When adults are ready to reproduce, they return to their natal river from the marine environment and spawn from March through August among gravel and stones in the lower to middle reaches of rivers. Juveniles make a slow descent downstream to the estuary and are present in the upper estuary at one year of age. Juveniles enter the sea after a 2 to 6 year period during which they alternate movement between the sea and the estuary.
Threats
Historical alterations to the European sturgeon’s habitat, including through gravel extraction from the riverbed and damming of the Dordogne and Garonne Rivers, have resulted in the decrease in number of accessible spawning grounds and therefore contributed to the low abundance and reduced spatial distribution of the species. Further, fishing for the species is prohibited throughout its range, and despite recent increases in compliance with fisheries prohibitions, bycatch in commercial benthic trawls and gillnet fisheries threatens reintroduction efforts and is considered to be the main threat to the remaining population and a main obstacle for the species’ recovery.
Scientific Classification
| Animalia |
Chordata |
Actinopterygii |
Acipenseriformes |
Acipenseridae |
Acipenser |
sturio |
