Allozyme frequencies indicate little geographic variation among stocks of giant tiger prawn Penaeus monodon in the south-west Indian Ocean

Abstract

The giant tiger prawn Penaeus monodon is an important component of prawn fisheries in the south-west Indian Ocean and the species of choice in prawn mariculture over much of the Indo-Pacific. Allozyme analysis of specimens collected between December 1996 and June 1997 from the Thukela Banks off KwaZulu-Natal, South Africa, the Sofala Banks off the Zambesi River in Moçambique and the north-western coast of Madagascar showed that, despite geographic separations of up to 2 000 km, Nei's unbiased genetic distance estimates between populations did not exceed 0.002. Mean heterozygosities within populations varied between 0.08 and 0.12 and allele frequencies were generally consistent with expectations under conditions of Hardy-Weinberg equilibrium. F_st values of 0.007 over all five populations sampled were not significant and indicate panmixis with high gene flow among all populations.