GENETIC VARIATION AND POPULATION STRUCTURE IN 



A DEEPWATER SNAPPER, PRISTIPOMOIDES FILAMENTOSUS, 



IN THE HAWAIIAN ARCHIPELAGO 



James B. Shaklee 1 and Paul B. Samollow 2 



ABSTRACT 



Pink snapper were collected from six different locations in the Hawaiian Archipelago and subjected to 

 starch gel electrophoretic analysis. Of a total of 44 enzyme-coding loci screened for genetic variation, 5 

 polymorphic loci were detected ( Adh, Gpi-A, Iddh, Ldh-C, and Umb). Each polymorphic locus exhibited 

 two common alleles (range of individual locus heterozygosity = 0.293-0.495). The heterozygosity 

 averaged over all 44 loci was 0.047. Observed genotype distributions at the five polymorphic loci were in 

 general agreement with Hardy-Weinberg equilibrium expectations. However, when the collections 

 were subdivided into two major age groups (fish about 2-5 years old vs. fish 5-14 years old), significant 

 differences in allele frequency between groups were detected for both alcohol dehydrogenase and 

 lactate dehydrogenase-C. 



Repetitive samples in 1979 and 1980 from two localities suggested that the allele-frequency distribu- 

 tions were stable during the period of the study. Contingency x 2 tests of the entire data set failed to 

 reveal significant genetic differences among the five primary localities (Maro Reef, French Frigate 

 Shoals, Necker, Molokai, and Hawaii ) or between the two major areas (Northwestern Hawaiian Islands 

 and main Hawaiian Islands) represented by the collections. The mean value of Wright's Fgf for the five 

 polymorphic loci was 0.005 indicating little subpopulation differentiation. 



The data fail to reveal significant genetic differentiation among localities. Indeed, the results are 

 entirely consistent with the existence of a single, panmictic stock of pink snapper throughout the 

 Hawaiian Archipelago. 



The pink snapper, or opakapaka, Pristipomoides 

 filamentosus, is a deepwater species found 

 throughout the Indo-West Pacific, including South 

 Africa, Japan, Australia, the Philippines, Samoa, 

 and the Hawaiian Islands (Kami 1973). In the 

 Hawaiian Islands it occurs in significant numbers 

 from Hawaii in the southeast through Maro Reef 

 in the northwest and is found in greatest abun- 

 dance at depths of 80-150 m (Ralston 1980). For the 

 past 15 or more years, this snapper has been the 

 dominant species in the deep-sea handline fishery 

 in Hawaii (Hawaii Division of Fish and Game 

 1960-80 3 ; Ralston and Polovina 1982). Due largely 

 to the developing fishery in the Northwestern 

 Hawaiian Islands (NWHI) the annual commercial 

 harvest of P. filamentosus has increased from 

 about 33 t in 1970 to 105 t in 1980 (Hawaiian 

 Division of Fish and Game footnote 3). 



'Hawaii Institute of Marine Biology, University of Hawaii, 

 Kaneohe, Hawaii; present address: Division of Fisheries Re- 

 search, CSIRO Marine Laboratories, PO. Box 120, Cleveland, 

 Qld. 4163 Australia. 



2 Hawaii Institute of Marine Biology, University of Hawaii, 

 Kaneohe, Hawaii; present address: Genetics Department, 

 Southwest Foundation for Biomedical Research, P.O. Box 28147, 

 San Antonio, TX 78284. 



3 Hawaii Division of Fish and Game. 1960-80. Commercial fish 

 landings. Mimeogr., var. pag. 



Spawning of pink snapper in Hawaii appears to 

 be concentrated in the fall of the year, and pre- 

 sumed annual fecundity may be as high as 1 x 10 6 

 eggs per female (B. S. Kikkawa 4 ). Fertilization in 

 opakapaka is external and the eggs are 

 planktonic. After hatching, the larvae remain 

 pelagic for about 1-2 mo during which time they 

 attain a size of 20-25 mm (J. Leis 5 ). Adults are 

 essentially demersal but virtually nothing is 

 known about the magnitude of adult movements, 

 either daily or seasonally. 



The present genetic investigation of stock struc- 

 ture in P. filamentosus was initiated to address 

 two questions relevant to the future management 

 of this fishery. First, was there any detectable 

 stock heterogeneity within the entire Hawaiian 

 Archipelago? Second, and specifically relating to 

 the potential impact of the emerging fishery in the 

 NWHI on the existing fishery in the main 

 Hawaiian Islands, was there evidence that popu- 



4 B. S. Kikkawa, Research Technician, Southwest Fisheries 

 Center Honolulu Laboratory, National Marine Fisheries Service, 

 NOAA, PO. Box 3830, Honolulu, HI 96812, pers. commun. June 

 1983. 



5 J. Leis, Research Fellow, Australian Museum, PO. Box A 285, 

 Sydney, N.S.W. 2000 Australia, pers. commun. April 1982. 



Manuscript accepted March 1984. 



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



703 



