The Invasive Atlantic blue crab Callinectes sapidus in Mediterranean waters: past, present, and future

The blue crab Callinectes sapidus Rathbun, 1896 (Decapoda, Brachyura, Portunidae), is native to the western coasts of the Atlantic Ocean, and was first recorded in Europe in 1900 on the Atlantic coast of France; in the Mediterranean Sea, the species was reported in the 50's (but probably as early as in the 30's). Subsequently, the species has progressively expanded its distribution, and is to date recorded in most coastal areas of the Mediterranean basin. Here we present an state-ofart overview of the investigations made in the last decade to monitor the distribution of C. sapidus, assess the structure and dynamics of established populations, and to investigate its functional role in invaded food webs in terms of trophic impact on native prey, vector of parasites, and involvement in the transfer of contaminants. The results of the synthesis are contextualized within the current efforts carried out in different European countries with a focus on Italy, as regards to the actions proposed for the Lesina Lagoon (FG) in the PO-FEAMP project “Catch Up Fish”, and the national project “Ecology and Impact of the Atlantic Blue Crab in the Spanish Mediterranean Coastal Lagoons and Adjacent Waters” (ECESIS) currently under evaluation in Spain. In addition, the ongoing collaboration with the University of Regensburg (Germany) aiming at investigating the molecular phylogeny of C. sapidus to assess the connectivity of Mediterranean blue crab populations is presented. The synthesis is expected to provide a robust basis for the identification of current Mediterranean-scale knowledge voids that necessitate to be addressed to support an effective risk assessment of the species in European waters, as well as future project proposals integrating effective policies of mitigation, control, and management of the species