Species Description: The Florida stone crab, Menippe mercenaria, is a member of the family Xanthidae and is the largest xanthid species in its region (Williams 1984). M. mercenaria has a large crusher claw with an enlarged basal tooth. The smaller pincer claw has many small teeth that can be used for cutting (Simonson 1985).
The adults appear dark brownish-red in color or less mottled with dusky grey spots. The walking legs are reddish with yellow bands. Juveniles appear dark purplish-blue and have a white spot on the carpus when they are very young (Williams 1984).
Regional Occurrence: Menippe mercenaria occurs on the east coast of the United States from North Carolina to Florida, in the eastern part of the Gulf of Mexico, and throughout the Caribbean to the Yucatan (Ong and Costlow 1970, Wilber 1989, Brown and Bert 1993). It occurs from 0-60 m and is usually found in the subtidal. The Florida stone crab lives in burrows in seagrass beds, oyster reefs and in crevices in rocks (Lindberg et al. 1990, Brown and Bert 1993).
IRL Distribution: The Florida stone crab is not common in the Indian River Lagoon (Boudreax et al. 2006).
Age, Size, Lifespan: Menippe mercenaria is the largest xanthid species. The males measure 91 mm in length and 129 mm in width. Females are smaller, measuring 79mm in length and 116 mm in width (Williams 1984). Female Florida stone crabs usually spawn at approximately 2 years of age, when the carapace measures 2.25-2.75 cm.
Abundance: When present in an estuary system, the Florida stone crab can occur in large densities (Lindberg et al. 1990).
Regeneration: Menippe mercenaria has the ability to regenerate claws that are removed as a defense mechanism or by other means, including harvesting for human consumption. Observations of the Florida stone crab indicate that these crabs are initially right handed. During regeneration there is usually a reversal of handedness in the crab where the pincer claw differentiates into a crusher claw and the removed claw is replaced by a new pincer claw. In an adult crab the pincer claw is replaced by a crusher claw within three molts. Juveniles readily replace the crusher in one molt. Some individuals of Menippe mercenaria are reported to regenerate two claws of 370 mm in length in as little as 6 months (Simonson 1985).
Reproduction: Menippe mercenaria has separate sexes. Spawning usually occurs between April and September. Under laboratory conditions, female stone crabs will spawn several times during a molting period throughout the year (Cheung 1969). In the field, females spawn every month but spawn most frequently during the warmer months from March to September (Sullivan 1979). Menippe mercenaria females carry the spawned eggs under the abdomen. Hybrid populations resulting from the pairing of Menippe mercenaria with Menippe adina are commonly found where these species co-occur (Wilber 1989).
Embryology: Menippe mercenaria has five zoeal stages and one megalopal stage (Porter 1960, Mootz and Epifanio 1974). In the laboratory, the Florida stone crab develops into the first crab stage within 27 to 30 days with each zoeal stage lasting 3-6 days and one molt per stage (Porter 1960).
Temperature: The temperature of the surrounding seawater is important in the reproduction and growth of Menippe mercenaria. Laboratory experiments with adult females demonstrated that the development of the ovary occurs as water temperatures increase (Cheung 1969). Other laboratory experiments reported the optimal temperature for larval growth was 30°C. As the temperature decreased, development slowed, and larvae did not survive past the megalopa stage when temperatures decreased to 20°C or less (Ong and Costlow 1970). For post-settlement juveniles of Menippe mercenaria, low water temperatures of 5 to 15°C inhibited molting. As the temperature was increased to 15°C, the ability to molt was restored (Brown and Bert 1993).
Salinity: Increased salinity does not have any significant effect on the survival of post-settlement juveniles of Menippe mercenaria (Brown and Bert 1993). However, decreases in salinity to 20-25 ppt will slow the development of larvae, and death occurs in the first zoeal stage at salinities of 10‰. The optimal salinity for larval development is 30-35 ppt (Ong and Costlow 1970).
Trophic Mode: Menippe mercenaria larvae are planktotrophic and can be reared in the laboratory on brine shrimp (Artemia nauplii) (Porter 1960). Adults use their large crushing claw to forage for bivalves such as hard clams (Mercenaria mercenaria) and ribbed mussels (Geukensia demissa) (Hughes and Grabowski 2006).
Associated Species: Menippe mercenaria has no known species associations.
Special Status: Florida stone crab season is from October 15-May 15.
Economic/Ecological Importance: The stone crab fishery is unique in that the animals are not killed. The claw is the only part of the crab that is harvested. The animal is then returned to the water to regenerate a new claw. Legal claw size for harvesting is a podus length of at least 70 mm. In 2006, the Menippe mercenaria claw fishery yielded approximately 2.5 million pounds of claws (Sullivan 1979, Simonson 1985).
Brown SD and TM Bert. 1993. The effects of temperature and salinity on molting and survival of Menippe adina and Menippe mercenaria (Crustacea, Decapoda) postsettlement juveniles. Marine Ecology Progress Series 99:41-49.
Cheung TS. 1969. The environmental and hormonal control of growth and reproduction in the adult female stone crab, Menippe mercenaria (Say). Biological Bulletin 136:327-346.
Hughes ARR and JH Grabowski. 2006. Habitat context influences predator interference interactions and the strength of resource partitioning. Oecologia 149: 256-264.
Lindberg WJ, Frazer TK, and GR Stanton. 1990. Population effects of refuge dispersion for adult stone crabs (Xanthid, Menippe). Marine Ecology Progress Series 66:239-249.
Mootz CA and CE Epifanio. 1974. An energy budget for Menippe mercenaria larvae fed Artemia nauplii. Biological Bulletin 146:44-55.
Ong K-S and JD Costlow. 1970. The effect of salinity and temperature on the larval development of the stone crab, Menippe mercenaria (Say), reared in the laboratory. Chesapeake Science 11:16-29.
Porter HJ. 1960. Zoeal stages of the stone crab, Menippe mercenaria Say. Chesapeake Science 1:168-177.
Simonson JL. 1985. Reversal of handedness, growth, and claw stridulatory patterns in the stone crab Menippe mercenaria (Say) (Crustacea: Xanthidae). Journal of Crusteacean Biology 5:281-293.
Sullivan JR. 1979. The stone crab, Mennipe mercenaria, in the southwest Florida fishery. Florida Marine Research Publications, Number 36. Florida Department of Natural Resources. pgs. 1-23
Wilber DH. 1989. Reproductive biology and distribution of stone crabs (Xanthidae, Menippe) in the hybrid zone on the northeastern Gulf of Mexico. Marine Ecology Progress Series 52:235-244.
Williams AB. 1984. Shrimps, Lobsters, and Crabs of the Atlantic Coast of the Eastern United States, Maine to Florida. Smithsonian Institution Press, Washington, D. C. pg. 420-424.