East meets west: competitive interactions between green crab Carcinus maenas, and native and introduced shore crab Hemigrapsus spp.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 225:251-262 (2002) - doi:10.3354/meps225251 East meets west: competitive interactions between green crab Carcinus maenas, and native and introduced shore crab Hemigrapsus spp. Gregory C. Jensen*, P. Sean McDonald, David A. Armstrong School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, Washington 98195, USA *E-mail: gjensen@u.washington.edu ABSTRACT: The recent introduction of the European green crab Carcinus maenas and Asian shore crab Hemigrapsus sanguineus to the west and east coasts of North America, respectively, presents a unique opportunity for investigation into competitive dynamics among intertidal crabs. Juvenile C. maenas utilize rocks, shell, and other cover, and their arrival on the west coast places them in potential competition for these resources with an abundant native grapsid, H. oregonensis. Similarly, H. sanguineus use intertidal shelter on the east coast, thus placing C. maenas in possible competition with grapsids both as an invader on the west coast and as Œresident¹ on the east coast, having been established there for more than 150 yr. Field sampling and laboratory experiments testing competition for space between C. maenas and Hemigrapsus spp. of equal carapace width were conducted on both coasts, as were videotaped feeding trials to examine and quantify agonistic interactions between species. When competing for food (a single damaged, anchored bivalve), C. maenas dominated over H. oregonensis, while H. sanguineus were overwhelmingly dominant over C. maenas. Within-quadrat, stratified sampling of rocks and sand revealed striking differences in habitat utilization by C. maenas living in the presence or absence of Hemigrapsus. Only ~20% of juvenile C. maenas occurred under rocks in areas occupied by either Hemigrapsus species, while north of the present distribution of H. sanguineus (in Maine) >97% of the C. maenas were found beneath rocks. This pattern was reflected in laboratory trials as well, where both species of Hemigrapsus consistently dominated in contests for shelter. Given the importance of intertidal cover for small crabs, such competitive interactions will likely affect patterns of habitat use by C. maenas on the east coast and may have important implications for the ultimate distribution and impact of this species in the northeastern Pacific. KEY WORDS: Carcinus maenas · Hemigrapsus oregonensis · Hemigrapsus sanguineus · Interspecific competition · Intertidal · Nonindigenous crabs · Shelter Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 225. Online publication date: January 11, 2002 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2002 Inter-Research.