872 



Fishery Bulletin 98(4) 



ulations then could have been isolated as a result of the 

 Andes uplift during the Pliocene Epoch, which altered the 

 pattern of the runoff and changed the course of the major 

 rivers of the Amazon basin. Runoff from the Amazon basin 

 continues to act as a barrier to lai-val migi-ation and effec- 

 tively separates Caribbean P. argus argus and Brazilian 

 P. argus westonii. Levels of nucleotide sequence diversity 

 observed between P. argus ai-gus and P. ai-gus westonii are 

 compatible with this hypothesis. 



Low numbers of the Brazilian form of P. argus in the 

 Caribbean may result from rare migration events or the 

 co-occurrence of both forms in the Caribbean. Long-range 

 dispersal of lai-vae is especially well developed in P. aigus. 

 The complex life cycle of spiny lobsters is characterized 

 by a protracted lai-val phase (the phyllosome) which can 

 last from several months to two years and can result in 

 prolonged transport by ocean currents (Sims and Ingle, 

 1967). Postlarval recruitment for some species of Panuli- 

 rus has been associated with variation in large-scale oce- 

 anic processes (Phillips and Pearce, 1997). El nirio-like 

 events could alter the current regimes and allow some of 

 the Brazilian forms of P. argus to escape into the Carib- 

 bean. Episodic recruitment events could also explain the 

 occurrence oiPanulirus laevicauda in the Caribbean. Pan- 

 ulirus laevicauda is abundant in Brazilian waters but 

 is only rarely found in the Caribbean. Evidence for spo- 

 radic recruitment of P. laevicauda in the Caribbean was 

 reported by Moore ( 1962), who noted finding a single spec- 

 imen of P. laevicauda near Palm Beach, Florida, during 

 1949. Later that same year, P. laevicauda was reported to 

 be nearly as abundant as P. argus. but in the following 

 three years, no P. laevicauda were found at this location. 



Occurrence of the Brazilian form of P. argus in Florida 

 waters raises a number of interesting biological questions. 

 Given the morphological differences and the high degree of 

 genetic differentiation between Caribbean and Brazilian 

 P. argus. are they capable of interbreeding? It could be pos- 

 sible that the existence of the Brazilian P. argus mtDNA 

 haplotype in the Caribbean could be the consequence of 

 leakage of the Brazilian P. argus mtDNA genome across 

 the species boundary as a result of interbreeding. Because 

 most of the research conducted with P. argus has been 

 done with Caribbean P. argus, do the two forms of P. ar-gus 

 differ biologically? George (1997) considers Brazilian and 

 Caribbean P. argus to be distinct ecologically and has sug- 

 gested that P. argus is likely a complex of two species. 

 Knowledge of the occurrence of P. argus ar-gus in Brazil- 

 ian waters is lacking. Taxonomic ambiguity surrounding 

 P. argus is a concern because of its commercial impor- 

 tance. For example, Florida regulations currently prohibit 

 the transportation or sale of imported P. argus during the 

 time of year when the fishery is closed in Florida. If two 

 species become recognized, under the present regulations. 

 Panulirus from Brazil could be sold year round in Flor- 

 ida. If there are indeed two species of P. argus in Florida 

 waters, as it appears there are, then fishery regulations 

 will need to reflect this reclassification. Currently, fishery 

 regulations apply to Panulirus ar-gus, and all subspecies of 

 spiny lobsters are subject to the same rules, but other spe- 

 cies are not regulated. 



Acknowledgments 



SKS would like to thank the CMSR Kimon T. Bird Visit- 

 ing Marine Scientist Program for support during a portion 

 of this study. This work was funded in part by NSF gi-ant 

 DEB-9726170toDWF 



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