Genetic diversity of hatchery stocks of giant freshwater prawn (Macrobrachium rosenbergii) in Thailand

The culture of freshwater prawn in central Thailand has experienced low productivity despite the rapid expansion during the past several years. Deterioration of genetic variation and inbreeding depression were blamed for slow growth rate in farmed stocks. Six microsatellite DNA loci were used to assess genetic diversity from five hatchery stocks and two wild populations of freshwater prawn. Natural populations were collected from the ChaoPhaya River and the Kraburi River. Two local hatchery populations originated from the ChaoPhya River were collected from the provinces of Nakorn Pathom and Supanburi. Another ChaoPhya originating samples were obtained from a hatchery in Indonesia. An introduced stock of Myanmar origin was sampled from a hatchery in Nakhon Pathom province and samples of a commercial strain which originated from India were collected in Ratchaburi province. All hatchery and wild populations exhibited relatively high genetic variation and were similar with an average of 7.50 to 10.67 alleles per locus and average expected heterozygosity at all loci of 0.64 to 0.73. Pair-wise comparisons and the FST values revealed significant genetic differentiation across all populations. Results indicated that poor performance of freshwater prawn due to deterioration of genetic variability and inbreeding was not an issue.