Population structure of the black tiger prawn, Penaeus monodon, among western Indian Ocean and western Paci®c populations

We examined the population structure of the black tiger prawn, Penaeus monodon Fabricius, 1798, in the Indo-West Paci®c by analyzing the geographic distribution of elongation factor 1-alpha intron sequences from specimens collected during the winter and spring of 1997. Both the molecular phylogeny of alleles and F-statistics indicated very strong di€erentiation between populations from the western Indian Ocean and western Paci®c. This pattern is concordant with other recent studies of marine species in this region, implying that the Indo-Australian Archipelago represents a biogeographic break between populations in the Indo-West Paci®c. FST-values among populations in the western Indian Ocean also indicate structure within this region, whereas no structure was found among western Paci®c populations. Nucleotide diversity was signi®cantly lower in the western Indian Ocean populations than in the western Paci®c, implying that the populations have regional di€erences in demographic history.