Feeding behavior and preference of the invasive blue crab (Callinectes sapidus Rathbun, 1896) for Mediterranean native bivalves in mesocosm

We investigated in mesocosm the feeding behavior and prey preference of the invasive blue crab Callinectes sapidus for different commercially exploited Mediterranean native bivalves. No-choice prey size and video-recorded prey-choice experiments were designed to test the following null hypotheses: (i) prey mortality do not vary when prey species are provided singularly nor with prey size; (ii) the predator does not have preferences when prey are provided simultaneously; (iii) manipulating, consuming, and handling times do not vary among prey species. We show that adult male C. sapidus individuals exhibit a cyclic feeding/resting behavior and a preference for Ruditapes decussatus, followed by Mytilus galloprovincialis and Cerastoderma glaucum. Based on our results, we anticipate that the preference of C. sapidus toward R. decussatus, one of the most important native commercial species in lagoons along the Italian coastline, could soon have consequences not only on the lagoons' trophic webs, but also on the local economy.