Microsatellites detect isolated populations of Caesio cuning in Malaysia and adjacent regions

We describe the use of seven hypervariable microsatellite markers to test for genetic differentiation among individuals from six populations of Caesio cuning (n=275) collected from Malaysia, Indonesia, Vietnam and the Philippines. C. cuning is a commercially important food fish harvested by both small scale and commercial fisheries. The species has a wide adult range and possesses pelagic larvae. We tested the null hypothesis that genetic differentiation does not exist in this region for populations of C. cuning. Variability was moderate among the loci with the average observed (H0 ) and expected (HE) heterozigosities ranging from 0.39 to 0.57 and 0.33 to 0.64 respectively. The global FIS value of 0.035 reflected a general deficit in heterozygotes. Both the pair-wise tests for genetic differentiation using FST and RST estimates and a classification-based assignment approach, revealed highly significant genetic subdivisions among each of the six populations tested. Pair-wise comparisons of allele frequencies yielded statistically significant p and 0 values of 0.346 and 0.390 respectively over all populations. Assignment tests showed that an average of 83.6% individuals was correctly assigned back to their original sampling site. Mantel\u27s test did not display significant correlation between genetic and geographic distances and the clusters defined based on Nei\u27s DA did not correlate with geographical position of populations. Gene flow and genetic connectivity in C. cuning appears to be confined within each of the populations which were separated by distances of 140 to 2440km