Westward range expansion of the blue swimmer crab Portunus segnis (Forskål, 1775) (Crustacea, Decapoda, Portunidae) into Atlantic European waters

Abstract

The introduction of non-indigenous species to aquatic ecosystems is one of the main threats to global biodiversity. This paper reports the occurrence of the blue swimmer crab Portunus segnis in southwestern European waters (i.e., the Gulf of Cadiz). We discuss the invasive potential of P. segnis and possible mechanisms of its expansion into this new region. The detection of this species also highlights the importance of involving citizen scientists in the reporting of non-indigenous species.