Second pilot release for the reintroduction of the sturgeon in the Ebre River

Another major step has been taken towards the recovery of the European sturgeon (Acipenser sturio) in Catalonia, Spain and Western Mediterranean. The first release of 44 specimens was carried out in December 2023 within the framework of the European LIFE MIGRATOEBRE project: a third part remained in the Ebre estuary until the end of January, and two thirds went to the sea immediately. A second pilot release of 50 European sturgeons will be carried out in the Ebre River on December 11. 

European sturgeon was present historically in the main rivers of the Iberian Peninsula. In the Ebre river, it arrived until Tudela (Navarra). It became extinct in the mid-20th century because of overfishing, pollution and the construction of dams and weirs, which limited its access to breeding areas. Beyond being known for obtaining caviar, sturgeons are the oldest vertebrate species living on the planet; they appeared in the dinosaur period. Currently, sturgeons are critically endangered around the world. The European sturgeon only lives, and still with great difficulty, in the basin of the Garonne and Dordogne rivers and in the nearby Atlantic Ocean.

This project has the collaboration of the French government, Nouvelle Aquitaine region, MIGADO association and the Institut National de Recherche en Sciences et Technologies pour l’Environnement et la Agriculture, and the support of the Ministry for the Ecological Transition and the Demographic Challenge of the Spanish Government, the Ministry of Territory, Housing and Ecological Transition of the Catalan Government, and the Institute for the Development of the Ebre Regions, with the participation of the IRTA Aquaculture Centre in La Rápita (Ebre delta) and the coordination of the Centre for Study of Mediterranean Rivers of the University of Vic-Central University of Catalonia.

The 50 sturgeons released this year, has been since November 14 at the facilities of the IRTA Aquaculture Center, where they are acclimatizing until the day of their release to the river, December 11. During this period, an external brand and ultrasonic emitters have been implemented, in order that researchers from the Center for the Study of Mediterranean Rivers of the University of Vic-Central University of Catalonia monitor their movements for a minimum of 6 months, which will donate information about their behaviour to the Ebre.

The Secretary of Ecological Transition, Jordi Sargatal, highlighted “the importance of restoring this species that had become extinct” and explained that “the intention is to carry out more releases as France can increase its reproduction until a viable population can be consolidated in the Ebro River”.

For his part, Marc Ordeix, coordinator of the Center for the Study of Mediterranean Rivers at UVic-UCC, stated that “from now on, it will be necessary to study the behavior of the released specimens and, for this reason, in this second release we have increased monitoring measures and have installed buoys with receivers in the sea to learn about their marine behavior, which is perhaps the most unknown stage of this species”.

Finally, from the Ministry for Ecological Transition and the Demographic Challenge, Jaime Castañer de Diego, from the Sub-Directorate General for Terrestrial and Marine Biodiversity, has highlighted the work done in recent years through the European project "LIFE MIGRATOEBRE" and has highlighted the importance of this type of initiative to promote biodiversity.