Synthesis of Escapements of Farmed Siberian Sturgeon in French Catchments: Some Extreme Events and a Lot Punctual Incidents

To assess the escapement of A. baerii in the French catchments, we propose in this chapter to gather different sources of data related to (1) the escapes related in the French national press between 1990 and 2015, (2) the gray literature and scientific articles that were produced following the largely mediatized escape of thousands of A. baerii in the Gironde estuary after the 1999 hurricane, and (3) the bycatch declaration of exotic sturgeon within the frame of the bycatch declaration procedure set for the indigenous species A. sturio (2007–September 2015). We highlighted in this chapter that the level of escape at the national scale is poorly known and that no official synthesis exists. But thanks to press article and bycatch declaration, we also highlighted that A. baerii escapes occurred in all the main coastal rivers of the Atlantic French coast. A quantitative synthesis based on escape declaration synthesis by A. baerii owners would greatly help to measure the threat of such escape for the native species. The main risk highlighted in the Gironde for the native species would be trophic competition, species confusion risk, and diseases that could be spread. Fortunately since the large escape of 1999, it seems that A. baerii did not reproduce in the Gironde watershed. But escapes from farm or pond are still regularly occurring on the French Atlantic catchment, quantitative data being scarce.