France was once home to the Atlantic sturgeon, previously unknown on its territory

This discovery is of major importance for programs for the reintroduction of sturgeons into European rivers.

These results, published in Comptes-rendus de l'Académie des sciences in mid-December, are a starting point for new research not only in archeozoology but also in paleoecology and paleogenetics, aimed at obtaining more information about these populations, which are in danger of extinction throughout the whole of Europe.

In France, the sturgeon is the largest fish that migrates to rivers in order to reproduce, while most of its growth takes place at sea. It is also one of the most endangered fish in Europe: there probably remain only a few tens or hundreds of individuals. Due to overfishing, dams, pollution and other factors that are harmful to the species, it has greatly declined in numbers since the beginning of the twentieth century. Today, it is in danger of extinction and has disappeared from most European rivers. In France, it can still be observed in the Gironde estuary, near Bordeaux. There has been a ban on the fishing of sturgeon since 1982. Research got under way in the late 1970s, and there is an ongoing restoration plan in France. In order to implement this plan properly, it is essential to know what the original (native) species are.

Until now, only the European sturgeon (Acipenser sturio) has been listed in France. However, other species may have been present in the past but no longer be present today. In order to identify them, scientists particularly make use of inventories, historical documents and museum collections. However, such sources of information are not always reliable. With regard to species that are no longer present, remains dug up from archaeological excavations represent the most reliable factual data. It is for this reason that Desse-Berset, an archeozoologist at CNRS, specialized in the morphological study of remains of sturgeons.

She studied remains from several archeological sites, in particular on the French Atlantic coast (Oléron Island, Gironde estuary, Vendée). She compared them with skeletons in her reference collection, which includes not only European sturgeons from the Gironde estuary, but also Atlantic sturgeons caught in Canada. Her conclusion is unequivocal: a second species of sturgeon, the Atlantic sturgeon (Acipenser oxyrinchus), is attested to on the French Atlantic coast at several periods, from prehistoric times until the second century AD. More specifically, Oléron Island and the Gironde estuary were home to two species of sturgeon at the end of the Neolithic, 5 000 years ago: the Atlantic sturgeon and the European sturgeon. These species co-existed in France for at least 3 000 years. This is the first time that the presence of another species of sturgeon in France has been demonstrated. No longer present in France today, this species is currently found along the Atlantic coast of North America.

This discovery provides information of major importance for sturgeon restoration projects in France. It also raises many questions about the history of sturgeon populations. These new results are the starting point for archeozoological research by Desse-Berset all over France. In addition, paleoecological and paleogenetic (mitochondrial and nuclear DNA) studies will be carried out in order to provide information about the genetic diversity of these recently extinct populations.

(1) Desse-Berset works at the Centre d'études Préhistoire, Antiquité, Moyen Âge (CEPAM, Université de Nice / CNRS).