- Carapace (shell) is smooth, heavy and thick
- Claws are enlarged, stout and dark tipped; one claw is usually larger
- Four blunt spikes along front of each side of carapace
- Four pairs of banded hairy legs
- Adults are tan or brown with gray spots, juveniles range in color from brown to purple
Gulf stone crab, M. adina; other crabs
Up to 5.5 inches in carapace width, with claws reaching 6 inches in length
Shallow water to offshore benthic environments, prefer sandy/muddy bottoms, rocky outcrops and seagrass beds. Can also be found in oyster bars, offshore reefs and rocky areas.
Feed on oysters and other small mollusks, polychaete worms, and other crustaceans. They will also occasionally eat seagrass and carrion.
Each time a stone crab molts, it can regenerate lost appendages. Juvenile crabs molt two or more times per year and can regenerate a lost appendage in just a few months. Adult crabs typically only molt once a year, therefore it takes a full year to regenerate a lost appendage. Large crabs of both sexes most likely never fully regenerate claws due to their relatively old age.
Female stone crabs mate after molting while the shell (exoskeleton) is still soft, which usually occurs in the fall (primarily September through November).
The number of eggs that a female can produce is relative to body size, ranging from tens of thousands to hundreds of thousands. A single female can produce four to six egg sponges per spawning season.
Claws can have a crushing pressure of 14,000 pounds per square inch. The larger of the two claws is called the "crusher claw.” The smaller claw is called the "pincer claw.”
Florida’s stone crab fishery makes up 99% of all stone crab landings in the United States. The stone crab fishery is unique in that only the claws are harvested, and the crabs are returned to the water. Harvest from egg-bearing females is prohibited.
The main harvest method used in both the commercial and recreational fisheries is a baited trap.