Abstract
American lobsters (Homarus americanus) and Jonah crabs (Cancer borealis) inhabit rocky subtidal areas where they take shelter in crevices or burrows. In previous studies, lobsters dominated crabs of equivalent size in competition for shelter; however, we predicted that large crabs could dominate small lobsters. SCUBA surveys revealed a broad overlap in size of lobsters and Jonah crabs cooccurring in Narragansett Bay, Rhode Island; thus, opportunity exists for interaction between animals disparate in size. In laboratory experiments, relative size did not affect the outcome of competition for shelter: lobsters were competitively superior to crabs of all sizes. However, some crabs excluded lobsters from shelter. Fish predation on lobsters increased significantly when shelter was limited, but predation on crabs did not. Crabs were able to escape predation by rapid burrowing, while lobsters were dependent on locating preexisting refuges. Differential vulnerability to predation may explain the lack of size effect in competition between lobsters and crabs. The cost of not obtaining shelter is lower for crabs than for lobsters; thus, crabs utilize alternatives rather than compete with lobsters.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Canadian Journal of Fisheries and Aquatic Sciences
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
