Juveniles . Small blue crabs (<1.6 inches CW) live in a variety of 

 shallow water habitats in the estuary (e.g., grass beds, muck bottoms) and 

 gradually move to deeper water as they grow larger. Adult size (>120 mm) is 

 achieved after 18-20 molts in 12-14 months. 



Adults . The size range of adults usually is 4.7-5.5 inches CW; they 

 enter the commercial fishery at 4.5 inches CW. Adult crabs are known to live 

 at least one more year, and a few may live 3 to 4 years. Primarily a shallow- 

 water species (<115 ft deep), adult blue crabs live in a variety of habitats 

 ranging from gulf waters with 34 ppt salinity to inland freshwater rivers up 

 to 121 mi from the coast. 



Diet . Blue crabs eat fish, aquatic vegetation, mollusks, (clams, mus- 

 sels, snails), crustaceans (amphipods, isopods), and insects and annelids. 

 Little is known of the food habits of larval crabs, but laboratory-maintained 

 animals have been successfully reared on photosynthetic dinoflagellates, brine 

 shrimp ( Artemia ) and sea urchin eggs ( Arbacia ). The megalopa is omnivorous 

 and will eat fish, shellfish, and aquatic plants. 



Stone Crab 



The stone crab ( Menippe mercenaria ) is another major Florida seafood 

 delicacy, but only its claws are used for food. Because new claws may be 

 regenerated, Florida law requires that stone crabs be released alive after 

 legal-sized claws are removed. 



Statewide stone crab landings increased steadily from 1970 (1.6 million 

 lb) to 1980 (3.9 million lb). Southwest Florida catches dominated statewide 

 landings and showed a similar increase. Stone crabs also are one of the five 

 most valuable seafoods. In 1980, the average dockside price was $1.43 lb and 

 the total value was over $5.5 million. A brief description of the life his- 

 tory of the stone crab is given in the following subsections (Sullivan 1979). 



Spawning . Adults spawn throughout the year, but primarily from April 

 through September. Most spawning females have a 2.25 inch carapace width (CW) 

 and are approximately 2 years old. The number of eggs is believed to increase 

 with the size of the female. Claws of legal size (3.5 inches minimum CW) are 

 first produced at 3 years of age. 



Larvae and juveniles . Stone crab larvae go through five zoea (plank- 

 tonic) stages and one megalopa (benthic) stage. Juveniles develop within a 

 month after hatching and first appear on shallow rock and shell substrates in 

 late spring or early summer. Juvenile crabs have been found in all adult 

 habitats. 



Adults . Adults are benthic, burrowing animals. They live at depths up 

 to 200 ft, but the fishery is largely confined to depths less than 100 ft. 

 Although some inshore to offshore movement is associated with reproduction, no 

 mass migrations have been reported. Males first enter the fishery as age 

 group II in the fall and as age group III in the winter. Most females of the 

 same age enter the fishery somewhat later. Most trapped crabs are 3 years old 

 and possess two legal-sized claws. Crabs 4 and 5 years old contribute jumbo 

 claws, and sometimes regenerated claws, to the fishery. 



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