The First Attempt at Studying the Species Diversity of Fish in Lake Khanka Using DNA Barcoding Techniques

Lake Khanka is the largest lake in the northeastern part of Asia, being a valuable part of the resources of freshwater fisheries. Lake Khanka has a low value of endemism owing to the recent origin and connection to large river systems of the Amur and Ussuri. The list of fish species present in the lake has been constantly updated owing to invasions that occur both unintentionally and because of the introduction of hydrobionts to maximize the potential of natural productivity. In this regard, the Lake Khanka is a suitable testing ground for the development and implementation of complex methods for monitoring species diversity. The cases of invasion have become more frequent in the lake recently. Moreover, the introduction of some fish species for stabilization of relationships among communities and exhaustive utilization of the natural productivity is now being carried out, which makes challenging the development and implementation of powerful techniques for monitoring of the local fauna species diversity. For the first time, we present a complex approach to the solution of that problem. We collected 64 fish specimens from 16 species representing four families of ray-finned fishes and analyzed their taxonomy and species diversity using both classic methods and DNA barcoding techniques. Specimens have been genotyped based on the mitochondrial Co-1 gene marker. The mean values of K2P-corrected intraspecific genetic distances were 0.15 ± 0.01%; the distances between different species within the same genera were 4.08 ± 0.01%. Phylogenetic analysis revealed monophyletic origin of all species clusters with high support (98–100% of bootstrap values). Thus, reciprocal complement of morphological and genetic techniques for the purpose of species delimitation and high effectiveness of DNA barcoding in application for documentation of species diversity in Lake Khanka has been demonstrated. New molecular genetic data generally are in agreement with taxonomic relationships previously shown for these fish taxa, but an additional investigation is required to verify the composition of genus Acheilognathus in Lake Khanka.