GENETIC VARIATION AND POPULATION STRUCTURE IN 



A SPINY LOBSTER, PANULIRUS MARGINATUS, 



IN THE HAWAIIAN ARCHIPELAGO 1 



James B. Shaklee 2 and Paul B. Samollow 3 



ABSTRACT 



Samples of the commercially important spiny lobster, Panulirus marginatus, were collected from 

 localities throughout the Hawaiian Archipelago and subjected to starch gel electrophoretic analysis of 

 protein variation. The amount and pattern of genetic variation exhibited by specific enzymes was 

 determined and analyzed to see whether or not there was evidence that the species was composed of 

 multiple stocks or subpopulations throughout its range. 



The lobster exhibited polymorphisms at 7 loci (Est-3, Umb, Gpi, Mpi, Pep-1, Pep-2, and Pgm) out of 

 the 46 enzyme-coding loci screened. However, genetic variability in the species was quite low, the 

 average heterozygosity for all loci was 0.021. Observed genotype distributions at the variable loci 

 agreed with Hardy- Weinberg expectations. Allele-frequency distributions for each locus were remark- 

 ably similar across localities and statistical tests failed to reveal clear patterns of genetic differentia- 

 tion within the Archipelago. The results are consistent with the existence of a single panmictic stock of 

 Panulirus marginatus throughout the Hawaiian Archipelago. 



The rational management of any fisheries re- 

 source, whether directed at exploitation, conser- 

 vation, or some other goal, requires many dif- 

 ferent types of information about the species in 

 question, and its interaction with environmental 

 and biological factors in its environment. Data on 

 basic biology (taxonomy, distribution and abun- 

 dance, food habits, behavior, etc.), ecological re- 

 quirements, reproductive characteristics, and 

 population dynamics are all relevant to manage- 

 ment decisions. Although the above types of in- 

 formation are necessary to any meaningful man- 

 agement plan, they are not sufficient. Information 

 concerning the stock or subpopulation structure of 

 the species is also of critical importance to the 

 formulation of any comprehensive, long-term 

 management program (MacLean and Evans 1981). 

 Subpopulations or stocks are generally consid- 

 ered to be self-sustaining subunits of a species 

 which are more-or-less reproductively isolated 

 from other such groups. It is reasonable to assume 

 that as a result of random processes and local 

 selection pressures, these subpopulations (stocks) 



1 Contribution No. 687 from the Hawaii Institute of Marine 

 Biology, University of Hawaii, Kaneohe, HI. 



2 Hawaii Institute of Marine Biology, University of Hawaii, 

 Kaneohe, Hawaii; present address: Di vision of Fisheries Re- 

 search, CSIRO Marine Laboratories, P.O. Box 120, Cleveland, 

 Qld. 4163 Australia. 



3 Hawaii Institute of Marine Biology, University of Hawaii, 

 Kaneohe, Hawaii; present address: Genetics Department, 

 Southwest Foundation for Biomedical Research, PO. Box 28147, 

 San Antonio, TX 78284. 



will become genetically differentiated from one 

 another. For this reason, the electrophoretic anal- 

 ysis of genetic characteristics provides one of the 

 most direct, and therefore theoretically powerful, 

 approaches to the problem of defining subpopula- 

 tion structure. However, it should be emphasized 

 that all tests of stock structure, including elec- 

 trophoretic ones, are really one-sided. It is actu- 

 ally only possible to establish the existence of mul- 

 tiple differentiated stocks by falsifying the null 

 hypothesis of a single, widespread, panmictic 

 stock. It is not possible to prove that only a single 

 panmictic population exists although the data (be 

 they genetic, morphological, behavioral, or what- 

 ever) may be consistent with this hypothesis. 



In the last decade, a substantial, multispecies, 

 commercial fishery has developed in the North- 

 western Hawaiian Islands (NWHI). This fishery is 

 directed almost exclusively at demersal species 

 and is dominated by catches of spiny lobsters 

 (Palinuridae), snappers (Lutjanidae), and group- 

 ers (Serranidae). Because of the largely unknown 

 and previously unexploited nature of this fish- 

 ery, a coordinated, large-scale, multidisciplinary 

 study involving personnel from the National 

 Marine Fisheries Service Honolulu Laboratory, 

 the U.S. Fish and Wildlife Service, the Hawaii 

 Division of Fish and Game, and the University of 

 Hawaii was initiated to describe, analyze, and 

 model the major components of the NWHI ecosys- 

 tem (Grigg and Pfund 1980). The genetic analysis 



Manuscript accepted March 1984. 

 FISHERY BULLETIN: VOL. 82, NO. 4, 1984. 



693-70,} 



