Microsatellite Markers Suggested Moderate Genetic Variation in Indian Mackerel (Rastrelliger kanagurta) Populations from the Andaman Sea, Thailand

Abstract

The Indian mackerel (Rastrelliger kanagurta) fi shery in Thailand has experienced declining catches during the past several years and was identifi ed as over-exploited. The study obtained population genetic information to support the ongoing management of the fi shery. Six microsatellite loci from short mackerel (Rastrelliger brachysoma) were screened to assess the genetic diversity in Indian mackerel stocks from four localities on the Andaman Sea coast. All population samples exhibited similar and moderate genetic variation with an average of 6.5 to 7.8 alleles per locus and average expected heterozygosity at all loci of 0.60 to 0.69. There was no evidence to support population substructure (overall genetic differentiation = FST = 0.012; non-signifi cant pairwise FST values). Gene fl ow was detected through the presence of rare alleles at three loci across samples. The contemporary estimated effective population size was approximately 330 if a single stock unit was considered. This moderate size of the breeding population is crucial for the short-term conservation of genetic variability in Indian mackerel stocks. Genetic data from the present study provides baseline genetic information and supports the management of Indian mackerel as a single unit.