Occasionally, when a live oyster or mussel is opened or "shucked" a small, bug-like organism is found inside the shell. This organism is commonly called a Pea Crab (Pinnotheres ostreum). This small crab, typically less than half an inch in length is soft-bodied and lives inside oyster shells for protection as well as for food particles which are discarded by the oyster.
This crab is generally not harmful to the oyster with which it lives, but at times can cause damage to the oyster's gills as it moves around inside the shell. The crabs are generally cream colored with large red spots, but may turn an orange color if the oysters are cooked prior to opening.
The crabs present no known adverse effects on quality or taste of oysters nor on the health of consumers.