At the mean growth rate of 0.51 mm CL/wk 

 observed for uninjured lobsters, it took about 51 

 wk for a juvenile to reach the minimum legal size 

 of 76.2 mm CL from a size of 50 mm CL at age 2 

 (Lewis 1951; Sweat 1968). At 50 mm CL they began 

 to associate gregariously with the larger juveniles 

 in the eastern bay where they were subjected to 

 fishery pressure. At the injury -depressed growth 

 rate of 0.31 mm CL/wk, it required 84 wk to reach 

 legal harvest size and enter the fishery 33 wk later 

 than uninjured lobsters. During the additional 33 

 wk required to reach legal harvest size, natural 

 mortality from groupers and other predators un- 

 doubtedly eliminated significant numbers of 

 lobsters before they could enter the fishery. Olsen 

 and Koblic (1975) estimated natural mortality of 

 juvenile P. argus in Virgin Islands National Park 

 at 34.8% /yr, at that rate, about 22% (33/52 of an- 

 nual mortality) of the injured lobsters in Biscayne 

 Bay were lost to the fishery as a direct result of 

 their injuries. By the end of the open season, about 

 half of the lobsters in Biscayne Bay were missing 

 several legs and/or antennae. The frequency of 

 injured lobsters dropped through the 4-mo closed 

 season to about 30%, as the population molted at 

 least once without harrassment from fishermen 

 (Table 1). Less than 25% of 963 juvenile lobsters 

 examined from an unfished population at Dry Tor- 

 tugas, Fla., displayed similar injuries, which were 

 presumably due to encounters with natural pre- 

 dators, difficulties with molting, or other normal 

 stresses (Davis unpubl. data). Fishery induced in- 

 juries reduced the yield per postlarval recruit by 

 reducing growth rate and consequently allowing 

 natural mortality to occur over a significantly 

 longer than normal period of time. 



Another aspect of injury slowed growth rates is 

 its effect on size of maturity. Maturity in spiny 

 lobsters is apparently more a Sanction of age than 

 size (Chittleborough 1974b). Therefore if growth 

 rate is significantly reduced by fishing activities 

 through injuries, the size of mature lobsters would 

 be reduced in areas of intense fishing activity. In 

 the light to moderately fished Dry Tortugas 

 fishery, the size of first maturity of female P. argus 

 was about 90 mm CL for most of the population ( 78 

 mm CL smallest ovigerous) (Davis 1975). In the 

 intensely fished lower keys fishery, the size of first 

 maturity was reported at about 80 mm CL (small- 

 est ovigerous 71.4 mm CL) (Warner et al. 1977). 

 However, while age induces onset of maturity, 

 female size is a major limit to fecundity. Creaser 

 ( 1950) pointed out that a single 130 mm CL female 



P. argus produced as many eggs as four 87 mm CL 

 females. Under the same environmental condi- 

 tions, a population of injury-stunted lobsters could 

 not produce the number of larvae that a popula- 

 tion of normal -sized animals would (Kanciruk and 

 Herrnkind 1976 ). Spawning fewer larvae may also 

 result in reduced genetic diversity in the P. argus 

 population, which would have further detrimental 

 consequences for the management of this valuable 

 resource (Miller 1979). 



Intense fishing pressure on commercial concen- 

 trations of spiny lobsters inflicts injuries in several 

 ways. Recreational divers inadvertently damage 

 juvenile lobsters in attempting to catch associated 

 larger animals, and by repeatedly catching nearly 

 legal-sized lobsters to measure them. Florida law 

 permits the capture, transportation, and use of 

 sublegal-sized juveniles for attractors (bait) in 

 commercial traps (Florida Statute 370.14), and 

 juveniles are occasionally caught in traps along 

 with adults. These sources of injury to the lobsters 

 are all amenable to standard lobster trap fishery 

 management techniques. Escape vents on traps 

 that would allow small lobsters to leave and a 

 prohibition on handling and transporting juvenile 

 lobsters could eliminate the sources of injury from 

 the trapping segment of the fishery (Bowen 1971). 

 Nursery sanctuaries in which no fishing activity is 

 allowed, and regulations prohibiting the use of 

 hooks and spears by divers could eliminate diver 

 and trap induced injuries. 



The response of P. argus to injuries is probably 

 representative of most tropical palinurids, and the 

 information developed here could have wide 

 application for fisheries management. 



Acknowledgments 



I would like to thank G. Y. Hendrix and J. A. 

 Kushlan for their assistance and encouragement, 

 and W F. Herrnkind and R Kanciruk for their 

 helpful critical review of the manuscript. 



Literature Cited 



AIKEN, D. E. 



1977. Molting and growth in decapod crustaceans, with 

 particular reference to the lobster Homarus 

 americanus. In B. F. Phillips and J. S. Cobb (editors), 

 Workshop on lobster and rock lobster ecology and physiol- 

 ogy, p. 41-74. CSIRO Div. Fish. Oceanogr, Circ. 7. 

 AUSTIN, C. B. 



1976. Recreational boating in Biscayne Bay. In A. 

 Thorhaug and A. Volker (editors), Biscayne Bay: Past/ 



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