1Kagoshima Prefecture Hokusatsu Regional Promotion Bureau, Satsumasendai, Kagoshima 896-1201, 2Department of Marine Biosciences, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, Japan
Genetic variability of natural and hatchery-released red sea bream in Kagoshima Bay and its vicinity was evaluated using three microsatellite DNA markers. Hardy-Weinberg equilibrium was found at all loci for each sample and even for all natural fish combined overall samples. Allele frequencies of IKB (natural fish caught in inner Kagoshima Bay) and hatchery-released fish caught in the bay were different from other natural samples. Observed mean heterozygosities and mean number of alleles per locus for IKB and natural fish caught in central Kagoshima Bay were high and similar to the results of previous studies for red sea bream. The results suggested that the large-scale hatchery releases for 30 years might influence the allele frequencies of IKB. However, the genetic diversity in the IKB has been maintained due to the large gene flow between the bay and its vicinity.