Genetic Diversity in Slender Walking Catfish (Clarias nieuhofii) Populations: Implications for Population Management

Random amplified polymorphic DNA (RAPD) markers were applied to assess the genetic diversity and population structure of the slender walking catfish ( Clarias nieuhofii , Clariidae) from 3 wild populations in peat swamp forests in southern Thailand (Surat Thani , Narathiwat, and Phatthalung). The selected 14 RAPD primers produced 105 RAPD bands, ranging from 6 to 11 bands per primer, and ranging in size between 400 and 3,000 bp. The percentage of polymorphic loci, gene diversity and Shannon’s information index values were 75.00 %, 0.2252, and 0.3443 for Surat Thani; 86.59 %, 0.2982, and 0.4441 for Narathiwat, and 96.25 %, 0.3371, and 0.5049 for Phatthalung, respectively. Among the 3 populations, the highest genetic distance (0.2213) was found between the Narathiwat and Surat Thani populations. High genetic differentiation ( G st = 0.2815) was detected in 3 populations with low gene flow ( Nm = 1.2762) among the overall populations. The clustering pattern obtained by the unweighted pair-group (UPGMA) method separated the C. nieuhofii samples into 3 groups, but 2 clusters. The results indicated a high level of genetic variation and genetic differentiation among C. nieuhofii from different populations in southern Thailand. This information would be useful to construct appropriate breeding programs, and could help conserve populations used as potential sources for stock management, restocking programs, and sustainable uses.