ABSTRACTMass‐culture experiments of stone crab (Menippe mercenaria) were successfully performed in 1970. Ovigerous female stone crabs were obtained from traps set in Biscayne Bay, Miami, Florida. The females were held separately in indoor aquaria. A maximum of 10 ovipositions (spawnings) within one inter‐molt phase were observed for a single female over a 120‐day period. During this period, the embryonic duration of the eggs was approximately 10 days at temperatures of 29 to 30 C, and the period between larval hatching and the female's next oviposition was 2 to 3 days.The duration of the larval period (five zoeal stages and one megalopal stage) was 14 days at temperatures ranging between 30.5 and 32.0 C, with salinity in excess of 30 ppt; 18 days were required at temperatures ranging from 28.0 to 30.0 C in the same salinity range. The time requirements in mass culture were found to be greatly reduced compared with individual compartment culture methods, which normally would take 20 to 21 days.Experiments using two different filtered seawater media were performed. In one, seawater was filtered through a 165 μ mesh screen; in the second seawater was filtered through a fine dacron wool filter. Results were similar.Initial larval culture media was stabilized by adding Chlorella to the culture seawater. The early zoeae were fed with separately cultured rotifers (Branchionus plicatilis) and Artemia nauplii. Only Artemia nauplii were provided for the late zoeal stages. The food for megalopae and juveniles was chopped fish and squid. To reduce cannibalism in the megalopal stages a screen‐ring was installed. This screen also provided a good substratum for settling.The maximum young crab yield was about 360 second‐stage crabs in a 200 1 plastic container, and 960 second‐stage crabs in a 600 1 capacity wooden tank. The best survival rate from hatching to the first crab stage was about 9%. Mortality occurred primarily in the magalopal stage.A promising future for stone crab culture is indicated from the growth rates obtained beyond the juvenile crab stage. Individuals reared separately in the indoor aquaria showed rapid growth. The most rapidly growing individual reached a carapace length of 9.1 cm and a weight of 236 g in 7 months from hatching. Approximately 10 molts are required to reach this size from the first crab stage. The color pattern of the cultured crab was noticeably different from that fou