Population structure of the climbing perch, Anabas testudineus, in the lower Mekong River basin.
Genetic variation in the climbing perch Anabas testudineus (Bloch) was investigated by sequencing 1047 base pairs of the mitochondrial ND2 gene. A total of 367 fish samples were collected from the Mekong River. The samples were separated into two genetically differentiated intra-specific groups, the Laotian and Cambodian group, showing a population structure roughly in accordance with geographical location. Genetic differentiation between groups was confirmed by high pairwise F-statistic values (0.52-0.98). Molecular clock analysis indicated that both populations were separated approximately 240 000 years ago. Additionally, samples within both groups could be divided into several regional small populations. Their genetic variation might have been supported not only by environmental factors including physical barriers, but also by historical events such as migration routes and/or timing of invasions into the Mekong River. These results could be valuable in identifying management units for the conservation of the species and its resource.