Yellows & Purples of Yellow Island: Characterizing the Hemigrapsus spp. On Yellow Island
In the Pacific Northwest region of the United States there are two Hemigrapsus species, the Purple Shore Crab (Hemigrapsus nudus) and the Yellow Shore Crab (Hemigrapsus oregonensis). Shore crabs are intertidal trophic linchpins, consuming intertidal algae and detritus, and serving as a food source for shore birds, sculpin and anemones. These closely related species are differentiated by a few striking differences; most identifiable are the spotted claws in the purple shore crab and hairy legs on the yellow shore crab. General field observations contradicted the literature as many crabs were observed lacking and/or having one or both of the major identifying features along with contradictory and/or undocumented color variation. Morphological methods of identification require updating and the inclusion of habitat preference to increase reliability. Working on Yellow Island, an island in the San Juan Islands of Washington state, crabs were sampled across various substrate types and tidal zones. Size, gender, carapace color and identifiable characteristics were recorded and analyzed. Statistical analysis revealed significant positive correlation between tidal zone and several characteristics despite only 15% of the crabs confirmed as either H. nudus or H. oregonensis. These species, while sometimes overlapping in habitat, do have habitat preferences. A change in the distribution or range of these crabs may be an indicator of changing habitat suitability thus possibly indicating changing distribution for other intertidal species.
Presentation Preference: Either
Primary Presenter: Benjamin Brown, University of Louisiana at Lafayette (benmbrown2025@gmail.com)
Authors:
Benjamin Brown, University of Louisiana at Lafayette (benmbrown2025@gmail.com)
Chris Mantegna, University of Washington (mantegna@uw.edu)
Camille Gaynus, Black In Marine Science (science@bims.org)
Tiara Moore, Black In Marine Science (ceo@bims.org)
Yellows & Purples of Yellow Island: Characterizing the Hemigrapsus spp. On Yellow Island
Category
Scientific Sessions > SS01 - ASLO Multicultural Program Student Symposium
Description
Time: 03:00 PM
Date: 27/3/2025
Room: W206A