Sturgeon Recovery Plan in the Rhône River (France): Preliminary Results on Species Determination and Habitat Suitability

Abstract

Sturgeons were living in the Rhone River (France) until their complete extirpation in the mid 1970s. They disappeared without a certainty about species identity and about sympatry between Acipenser sturio and Acipenser naccarii, as occurred in the Po and Guadalquivir rivers. Preliminary studies were launched in 2005 by the Migrateurs Rhone Mediterranee (MRM) association to overcome this lack of knowledge and to evaluate the lower Rhone River environment suitability for sturgeon. Twelve sturgeon specimens froth the Rhone River and the French Mediterranean coast were found in museums and samples for genetic analyses were taken from 10 of there (analyses in progress). Genetic analyses (cytochrome b) on five sturgeon bone remain (among 2500 remains available) samples more than 2000 years old found in the city of Arles, close to the Rhone River, clearly show that A. sturio was living in this river. Morphological comparisons between ancient bone remains and recent skeletons from A. sturio and A. naccarii are in progress. Environment studies show the existence of possible suitable habitats for sturgeon in the Rhone river, mainly spawning and feeding grounds. This should be confirmed by more precise studies. All these preliminary results are very encouraging regarding the possible restoration of sturgeon in the Rhone River.