Relationship between Depth and Occurrence of Pea Crabs, Pinnotheres maculatus, in Blue Mussels, Mytilus edulis, in the Vicinity of Woods Hole, Massachusetts

Blue mussels, Mytilus edulis, were collected from eight sites near Woods Hole, Massachusetts and examined for presence of the symbiont, Pinnotheres maculatus. Mussels (550) from 6 intertidal areas contained 2 crabs. Mussels (421) from 2 subtidal areas contained 238 crabs. Only 1% of mussels growing near the surface on a piling contained crabs, while those from depths of 10 feet and below were highly infected.