Gulf and Florida Stone Crabs (Menippe adina and Menippe mercenaria)

• Stone crab population levels are estimated to be high and no overfishing is occurring.
• The unique manner in which stone crab claws are harvested helps ensure the long-term sustainability of the species.
• Stone crabs are a good, low-fat source of protein, vitamin 6, selenium and magnesium. For more on nutrition, see Nutrition Facts. (USDA).
• All of the stone crab claws on the market come from wild fisheries; there is no aquaculture for stone crab claws.

Sustainability Status

Biomass: Unknown
Overfishing: No
Overfished: Undefined
Fishing and habitat: Stone crabs are harvested primarily with wooden or plastic traps. Traps can potentially damage bottom habitat if they are deployed and retrieved from coral reefs or live hardbottom. Seagrasses can also be damaged by placement and retrieval of traps.
Bycatch: Mostly invertebrates, such as mollusks and other crabs, and some small finfish. A degradable trap escape panel has been required since 1979 to reduce bycatch. There have been no marine mammal interactions documented with the trap and pot gear used to catch stone crabs.
Aquaculture: Commercial mariculture of stone crabs has been considered since the late 1960s due to highly variable commercial landings coupled with high market demand and premium prices for stone crab. The most recent attempts at mariculture show that major hurdles, such as large space requirements and the aggressive nature of the animal, must be overcome before commercial production of stone crab is successful.

Science and Management

The stone crab fishery in the Exclusive Economic Zone (EEZ) off the west coast of Florida in the Gulf of Mexico (Gulf) is managed through the Gulf of Mexico Fishery Management Council's Fishery Management Plan for the Stone Crab Fishery of the Gulf of Mexico (FMP), implemented on September 30, 1979. The FMP extended Florida's rules regulating the fishery into the EEZ. Only legal-sized claws (2 ¾ inches) are harvested in the stone crab fishery; crabs are returned to the water alive to generate new claws. Approximately 13 percent of commercially harvested claws are regenerated. The fishing season is open October 15 through May 15 each year, but the harvest of egg-bearing female crabs is prohibited at all times. In 2002, Amendment 7 created a passive trap reduction program for the EEZ that complements a similar program for the Florida fishery.

Life History and Habitat

Life history, including information on the habitat, growth, feeding, and reproduction of a species, is important because it affects how a fishery is managed.

• Geographic range: Gulf stone crab are found from northwest Florida around the Gulf of Mexico to the state of Tamaulipus, Mexico. Florida stone crab are found from west central Florida around the peninsula to east central Florida and North Carolina. An extensive hybrid zone occurs from the big bend area of Florida to west central Florida, and a smaller hybrid zone occurs from east central Florida through South Carolina. A hybrid zone is where the range of the two interbreeding species meet.
• Habitat: Larvae are planktonic and are found in nearshore coastal waters and within estuaries. Juveniles inhabit hiding places such as crevices in and beneath rock or shell. Adult Gulf stone crabs are found on mud flats and oyster reefs in nearshore and estuarine areas. Adult Florida stone crabs live in seagrass beds or rocky substrate in higher salinity waters.
• Life span: Males live to about 7 years, and females live to about 8 years.
• Food: Larvae feed on smaller zooplankton (tiny floating animals). Juvenile and adult stone crab are generally opportunistic carnivores but sometimes eat plants also. Juveniles and adults both feed on oysters, acorn barnacles, conchs, sea anemones, flatworms, boring clams, blue crabs, hermit crabs, common mussels, and vegetative matter.
• Growth rate: Growth in males is greater and more variable than in females.
• Maximum size: Stone crabs can reach 5 ½ to 6 inches carapace width (the widest part of the body).
• Reaches reproductive maturity: Females mature at around 2.4 inches carapace width; males mature at around 2.8 inches carapace width. The carapace is the part of the exoskeleton that covers the first section of the crab's body.
• Reproduction: Stone crabs mate after molting when the female is soft. Males deposit spermatozoa in the receptacle of the female. Eggs are fertilized within the ovary lumen. After fertilization and ovarian development, eggs are deposited in an external mass or sponge (160,000 to 1 million per egg mass) beneath the female abdomen. At this time, females are termed ovigerous, or egg-bearing. Eggs usually hatch within two weeks after they are extruded. Larval development takes approximately four weeks before metamorphosis to the juvenile form.
• Spawning season: Spring to fall
• Spawning grounds: Mating sites have not been identified, but research has suggested that oyster reefs and seagrass beds may be important habitat for mating.
• Migrations: Little is known about the movement and migration of stone crabs. They may move in response to environmental factors or seasons. Large males appear to move inshore in the fall to mate with molting females.
• Predators: Adult filter-feeding fish, larval fish, and other zooplankton feed on larval stone crab. Predators of juveniles include other xanthids (crustaceans), grouper, black sea bass, and other large fish. Octopi, horse conchs, sea turtles, cobia, and grouper feed on adult stone crab. Juvenile stone crabs are more susceptible to predators than adults because they do not burrow or have the large claw of adults.
• Commercial or recreational interest: Both
• Distinguishing characteristics: Stone crabs have a large crusher claw and a smaller pincer claw with numerous small teeth used for cutting. The Gulf stone crab is maroon brown, as compared to the Florida stone crab which is spotted and banded.

Role in the Ecosystem

Stone crab burrows provide habitats for a wide variety of invertebrates and fish that use the burrows for protection, food, and survival.

Additional Information

Market name: Stone Crab

Biomass

Biomass refers to the amount of stone crab in the ocean. Scientists cannot collect and weigh every single stone crab to determine biomass, so they use models to estimate it instead. These biomass estimates can help determine if a stock is being fished too heavily or if it may be able to tolerate more fishing pressure. Managers can then make appropriate changes in the regulations of the fishery.

The stone crab fishery is unique in that stone crabs are not killed but, rather, the legal-sized claws are removed and the crabs are returned to the water alive. There are no biomass estimates for stone crab; the condition of the stock is instead assessed by examining landings and effort in the fishery. The current status of stone crab is best indicated by the stable landings after 1989-90.

Landings

Landings refer to the amount of catch that is brought to land. Only Texas and Louisiana have reported landings for Gulf stone crab. Directed fishing for Gulf stone crab is limited; only a few fishermen target stone crabs by locating blue crab traps near hardbottom substrates such as oyster reefs and jetties.

Seasonal landings of Florida stone crab claws were less than 500,000 pounds until 1967-68. Florida's gulf coast landings increased to 1 million pounds by 1973-74. The landings of stone crab claws continued to increase until 1998, after which landings decreased slightly. Recent landings have exceeded 3 million pounds.

Note: Only Florida stone crab commercial landings are shown in the graph.

Biomass and Landings

Are landings and biomass related? Landings are dependent on biomass, management measures in the fishery, and fishing effort.

Data sources:
Landings from Florida Fish and Wildlife Conservation Commission's 2006 Stock Assessment Update for the Stone Crab Fishery in Florida

Important Dates

1979 – FMP for the Stone Crab Fishery of the Gulf of Mexico implemented
1982 – Amendment 1 specifies procedure for modifying zoned area to resolve gear conflict
1984 – Amendment 3 includes management measures to enhance survival of crabs held onboard vessels and prohibits harvest of egg-bearing female crabs; also rescinds logbook reporting provision and substitutes the Florida trip ticket system
1991 – Amendment 4 contains provisions to define overfishing, a section on vessel safety considerations, and a revised habitat section
1995 – Amendment 5 places a 3-year moratorium on the registration of stone crab vessels because Florida proposed a state moratorium on issuance of permits while the industry considered development of a limited access system; also includes protocol for implementing rules in the EEZ proposed by the State of Florida and updates habitat description
1998 – Amendment 6 extends moratorium through June 30, 2002
2002 – Amendment 7 creates a trap reduction program for the EEZ, complementing a similar program for the Florida fishery

Notes and Links

General Information:
Florida Fish and Wildlife Conservation Commission

Fishery Management:
Gulf of Mexico Fishery Management Council Stone Crab Fishery Management Plan

Florida Recreational Regulations

Florida Commercial Regulations

Stock Assessments:
2006 Stock Assessment Update for the Stone Crab Fishery in Florida