Risk screening of the potential invasiveness of non-native marine crustacean decapods and barnacles in the Mediterranean Sea

Non-native marine crustaceans can exert detrimental impacts on native marine communities by altering habitat and ecosystem function. The Mediterranean Sea is particularly vulnerable to introductions of non-native crustaceans, as evidenced by their remarkably high establishment success. In this study, 20 species of non-native marine crustacean decapods and barnacles of which eleven extant and nine 'horizon' were screened for their potential invasiveness in the Mediterranean Sea. Using the Aquatic Species Invasiveness Screening Kit and including an additional nine native species to increase accuracy, calibrated risk thresholds of 3.5 for the BRA (Basic Risk Assessment) and 8.5 for the BRA + CCA (BRA + Climate Change Assessment) were obtained that distinguished reliably between invasive and non-invasive species. All 20 non-native species were classified as carrying a high risk of invasiveness for the Mediterranean Sea, both for the BRA and the BRA + CCA. Chinese mitten crabEriocheir sinensiswas by far the highest risk species, followed by Harris mud crabRhithropanopeus harrisii, Asian shore crabHemigrapsus sanguineus, bay barnacle,Amphibalanus improvisus, and lesser swimming crabCharybdis (Goniohellenus) longicollis. The findings of this study will provide management and control directions for non-native marine crustaceans in the Mediterranean Sea, with special emphasis on regulations regarding ballast waters, which represent one of the main introduction pathways for these aquatic organisms.

Automated summary

This study found that all 20 non-native marine crustacean species in the Mediterranean Sea carry a high risk of invasiveness, with the Chinese mitten crab Eriocheir sinensis being the highest risk species. These findings will provide management and control directions for non-native marine crustaceans in the Mediterranean Sea, with a focus on regulations regarding ballast waters.