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 [Macoma balthica (Linneaus, 1758)]. Crabs infrequently chose quahogs [Mercenaria mercenaria (Linneaus, 1758)], and only small individuals. Six dietary groups were documented in stomachs of crabs captured in the field; arthropods, molluscs, and vegetation were common stomach contents. Twelve molluscan species were detected throughout EH, many of which likely serve as prey for green crabs. Although mollusc abundance in EH has fluctuated because restoration began, the mollusc community remains sufficiently diverse and abundant to provide ample food for green crabs. In this nascent, simplified system, green crabs have few if any predators and thus may exert greater influence as a predator in EH than in other, more well-developed benthic communities.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 36 • No. 1