Population genetics of red spiny lobster (Panulirus interruptus) along the Baja California Peninsula, Mexico

Abstract

Analysis of the genetic structure of the red spiny lobster (Panulirus interruptus) population was conducted along the Baja California Peninsula, Mexico. Samples for allozyme analysis came from Ensenada, Punta Eugenia, Punta Abreojos, San Juanico, and Bahia Magdalena (about 50 individuals each). Of 16 loci analysed, five were polymorphic (95% criterion) in at least one subpopulation. A significant mean value of F_IS = 0.125 indicated some subpopulations departed from Hardy-Weinberg expectations; increased homozygosity was particularly evident for alleles EST-2*b and LAP*a at Ensenada and EST-2*c and EST-4*c at San Juanico. MeanF_ST = 0.101, which included 99% criterion polymorphic loci, was significant (P < 0.05), supporting a genetic structure throughout the species’ geographical range. Pairwise heterogeneity and FST tests showed no significant differences in allele frequencies between Punta Eugenia and Punta Abreojos, but several pairwise comparisons among the other locations, especially at the most variable loci, showed significant differences, supporting a hypothesis of genetic differentiation of P. interruptus into three subpopulations: southern, central, and northern Baja California. Oceanographic processes, such as semipermanent eddies south of Punta Eugenia that tend to retain phyllosoma larvae, may help generate this pattern. The implications of these findings for the management of the resource are also considered.