to the coasts of North America. Like many other sturgeons, they spawn in the rivers inland from the coast. The species can tolerate wide spread salinities and spend most of their lives in saltwater but migrate to spawn in freshwater. Conservation At the beginning of the 19th century, these fish were used extensively to produce caviar, but have been a protected species in Europe since 1982. Despite their estimated range of distribution, they have become so rare that they only breed in the Garonne river basin in France. Conservation projects involving this species include reintroductions based on specimens from aquaculture with the first releases in 1995. For example, 87 sturgeons were experimentally released in the Rhine near Nijmegen in 2012 and 2015. Diet Like other sturgeons, they eat polychaete worms and crustaceans which they find with their barbels. Threats Historical habitat changes to the European sturgeon, such as gravel extraction from riverbeds and damming of the Dordogne and Garonne Rivers, have resulted in a reduction in the number of available spawning sites, contributing to the species' low abundance and regional dispersion. Furthermore, despite recent gains in compliance with fisheries bans, bycatch in commercial benthic trawls and gillnet fisheries threatens reintroduction attempts and is regarded the biggest threat to the remaining population and a major impediment to the species' recovery. Population Although no specific population estimates are available, the abundance of wild, mature European Sturgeon is estimated to be less than 800 individuals. The last time the species hatched was in the Garonne River in France in 1994, and genetic analysis reveals that the 1994 cohort was formed by only one mating pair. Because the wild population is so small, a captive breeding and stocking program is vital to the species' survival. Although restoration operations, such as artificially bred individual restocking, have been successful in the Gironde estuary and the Elbe River (Germany), recovery for the European sturgeon is a long process that might take 30-50 years. Bycatch in commercial trawls and gillnets, pollution, climate change, and potential competition with other species are all dangers to the species right now. Scientific Classification References External links ARKive - images and movies of the European sea sturgeon(Acipenser sturio) European sea sturgeon Fish of the Atlantic Ocean Fish of the North Sea Freshwater fish of Europe Marine fish of Europe Critically endangered fish Critically endangered biota of Europe European sea sturgeon Taxa named by