Selection and Availability of Shellfish Prey for Invasive Green Crabs [Carcinus maenas (Linneaus, 1758)] in a Partially Restored Back-Barrier Salt Marsh Lagoon on Cape Cod, Massachusetts

ABSTRACT European green crabs (Carcinus maenas) are voracious, invasive predators of molluscs and their range is expanding throughout the northwest Atlantic Basin. Green crabs rapidly established following the 2002 partial restoration of East Harbor (EH) (42″039330 N, 70″079430 W), a back-barrier salt marsh lagoon within Cape Cod National Seashore, MA, where crabs potentially contribute to abrupt shifts in bivalve abundance and compromise restoration outcomes. Green crab prey preferences and effects on molluscan assemblages at this site have not been documented. Between June and September 2013, the prey selections of green crabs were documented using mesocosm feeding experiments and green crab diet through stomach content analyses. To evaluate prey availability, molluscan assemblage characteristics were also characterized using benthic coring. In the mesocosm experiments, green crabs strongly preferred large softshell clams [Mya arenaria (Linneaus, 1758)] and also chose small M. arenaria and Baltic clams ...