Panulirus argus reach sexual maturity at lengths of approximately 70 - 80 mm (2.8 - 3.2 inches) (Witham et al 1968. Olsen et al 1975, Davis 1979). Adult male and females often inhabit estuaries, bays, and lagoons; but spawning typically occurs in nearshore and offshore reef fringes and other hardbottom areas from late spring through summer in Florida waters (Davis 1975; Kanciruk and Herrnkind 1976; Lyons et al. 1981). Annual variation in peak spawning period is dependent on water temperature. Lyons et al. (1981) reported spawning begins when water temperatures reach 24º C in deeper reef areas. In Florida, there is little evidence that spiny lobsters spawn more than once per year; however, in Bermuda, evidence supports multiple spawning (Sutcliffe 1952). Mating follows short courtships that involve signals being given by both sexes. In copulation, males hold females sternum to sternum and extrude a spermatophore which is adhered to the female's sternum, and will remain until the time of spawning. Sperm may be viable for as long as a month (Marx and Herrnkind 1986). Spawning occurs when females flex the abdomen under the carapace, spreading the telson and uropods, as well as the pleopods. Eggs are shed onto the abdomen, while the female scratches at the spermatophore to liberate sperm and fertilize eggs as they are extruded. Fecundity varies with body size. Females 71-75 mm (2.8 - 3 inches) in length carry approximately 230,000 eggs; while females over 100 mm (3.9 inches) carry more than 700,000 eggs (Mota-Alves and Bezerra 1968). Williams (1984) reported females 23 cm (9.1 inches) with 500,000 eggs, 30 cm (11.8 inches) with 1.18 million eggs, and 38 cm (15 inches) with 2.6 million eggs. Using the Index of Reproductive Potential (IRP) Lyons et al. (1981) estimated that female Panulirus argus in the upper Florida Keys measuring 76-85 mm (3.0 - 3.3 inches) carapace length (CL) contribute 48% of all egg production in the population. Females over 85 mm (3.3 inches) CL comprise approximately 20% of the female population, but contribute 41% of egg production. Females smaller than 76 mm (3.0 inches) comprise approximately 25% of all females, but contribute 11 % of all eggs. Minimum spawning size has declined in Florida Panulirus argus females, perhaps as a response to intense fishing pressures. In 1922, minimum spawning size of females was reported to be 76mm (3.0 inches) (Crawford and De Schmidt 1922). Recent surveys have revealed reproductive females as small as 65 mm- 71 mm (2.6 - 2.8 inches) in south Florida (Warner et al. 1977; Lyons et al 1981). However, unfished populations in the Dry Tortugas area show the minimum size in egg-bearing females to be 78 mm (3.1 inches) (Davis 1975). Suggested reasons for this decline in minimum spawning size have been genetic selection; modified sexual behavior when large females become rare; and reduced growth rates (Davis 1975; Warner et al. 1977; Lyons et al 1981). Decline in size of mature females has caused a marked reduction in reproductive potential, with Lyons et al. (1981) estimating that egg production in Florida Keys spiny lobsters was only 12% of that expected from a similarly sized, unfished population (Lyons et al. 1981).
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