Larval connectivity of the invasive blue crabs Callinectes sapidus and Portunus segnis in the Mediterranean Sea: A step toward improved cross border management

Abstract

The two invasive blue crabs, Callinectes sapidus and Portunus segnis have spread rapidly in the Mediterranean and no data exists on the connectivity of populations. Determining the source and recruitment areas is crucial to prioritize where population control measures should be put into immediate action. We simulated the dispersal of blue crab larvae using a Lagrangian model coupled at high resolution to estimate the potential connectivity of blue crab populations over a 3-year period. Our results reveal that the main areas at risk are the Spanish, French, Italian Tyrrhenian and Sardinian coasts for Callinectes sapidus with high populations connectivity. Tunisia and Egypt represent high auto recruitment zones for Portunus segnis restricted to the central and western basins. This study provides an overview of the connectivity between populations and will help define priority areas that require the urgent implementation of management measures.

Keywords: Blue crabs; Connectivity; Cross-border management; Invasion risk; Larval stage; Mediterranean Sea.