714 



Fishery Bulletin 88(4), 1990 



Figure 1 



Location of Maro Reef and Necker Island within the Hawaiian Archipelago. 



tion among populations was detected, and they con- 

 cluded that a single panmictic stock of spiny lobster 

 exists throughout the Hawaiian Ai'chipelago. 



Our objective was to reexamine allozyme variation 

 at those seven loci to determine if fishing pressure since 

 1980 affected population structure or genetic variabil- 

 ity. During 1987, new collections of spiny lobsters from 

 two of the same localities in the northwestern Hawaiian 

 Islands (Maro Reef and Necker Island) were made. 

 These two sites represent the mainstay of the commer- 

 cial fishery. They are the most [productive banks, have 

 been fished the longest, and annually receive the 

 greatest fishing pressure. 



Analysis showed that the observed number of allelic 

 classes and observed heterozygosity have remained 

 essentially unchanged between 1978 and 1987. These 

 data provide no evidence that population bottlenecks 

 have occurred. Fishing pressure since 1980 has not 

 reduced the genetic variability as detected by protein 

 electrophoresis in spiny lobster from either of these two 

 sites in the northwestern Hawaiian Islands. 



Methods and materials 



Muscle and digestive gland from 200 specimens from 

 Maro Reef and Necker Island (Fig. 1) were collected, 

 frozen onboard ship, and shipped frozen to the labor- 

 atory for analysis. Upon receipt, tissues were sub- 



sampled for electrophoresis and stored at -80°C for 

 up to 4 weeks while analysis was completed. 



Electrophoretic methods generally followed May 

 et al. (1979) and Shaklee and SamoUow (1984) to facil- 

 itate comparison. Samples were analyzed for the pro- 

 ducts of seven loci previously identified as polymorphic: 

 EstS, Esterase, E.G. 3.1. L-; EstD (Umb), Esterase, 

 E.G. 3.1.-.-, resolved with 4-methylumbelliferyl ace- 

 tate; Gpi, glucosephosphate-6-isomerase, E.G. 5.3.1.9; 

 Mpi, mannose-6-phosphate isomerase, E.G. 5.3.1.8; 

 Pgtn. phosphoglucomutase, E.G. 5.4.4.2; Tpepl.2 

 (Pep-lJ), tripeptidase aminopeptidase, E.G. 3.4.-.-, 

 resolved with L-leucyl-L-leucyl-L-leucine. However, in 

 contrast to the methods of Shaklee and Samollow 

 (1984) who used horizontal and vertical gels, all anal- 

 yses were performed on horizontal starch gels. Tjh'jiI 

 was resolved on an additional buffer, amine-citrate gel 

 and tray buffer, pH 6.9 (Glayton and Tretiak 1972). 



The electrophoretic data were analyzed using 

 BIOSYS-1 (Swofford and Selander 1981). Allelic 

 classes followed those of Shaklee and Samollow (1984), 

 who pooled alleles into f(fast), m(medium), and s(slow) 

 classes for numerical analyses. Pooling was required 

 in their study and ours because many alleles were too 

 rare to include in the statistical tests. Actual mobilities 

 observed were also recorded. 



Gomparisons between the 1978-80 and 1987 data 

 sets for each reef were performed using a chi-square 

 contingency analysis based on the number observed in 



