Allozyme variation in hatchery populations ofsilver and bighead carps in Bangladesh

Abstract

To elucidate allozyme variation, silver (Hypophthalmichthys molitrix) andbighead (Aristichthys nobilis) carps of three hatcheries were analyzed usingseven enzymes and five of them showed clear banding pattern producing tenpresumptive loci. Among the ten loci, Mdh-1* in silver carp and Mdh-2* in bigheadcarp populations were found to be polymorphic.  The mean proportion ofpolymorphic loci per population (8.33±7.22%) and mean proportion ofheterozygous loci per individual (2.22±1.92%) were higher in silver carp than inbighead carp populations (3.33±5.77% and 1.11±1.92%, respectively). UPGMAdendrogram showed that Maskanda and Parbatipur population made one clusterand separated from Brahmaputra in both silver and bighead carps by the Dvalue of 0.016 and 0.05, respectively. These results indicate that the loss ofgenetic diversity in the existing stocks of silver and bighead carp populationsmight be due to use of small number of founder stock and it needs to be furtherrestocked in Bangladesh from their original sources.