To further clarify the taxonomic status of species in the Suifen River in China, COI gene sequences of 53 samples including , their suspected hybrids in Suifen River, and , which was collected from Japan, were compared and analyzed. Eight haplotypes were obtained with an effective sequence length of 637 bp. Haplotype analysis showed that had three haplotypes, whereas collected from Japan had an independent haplotype. Although the suspected hybrids shared two haplotypes with their parents, 80% individuals shared the same main haplotype with . Phylogenetic analysis using the neighbor-joining method based on the K2P model showed that in the southern region of Russia (i.e., Primorsky krai), T. hakonensis in the northern region of Russia (i.e. Sakhalin Island and Khabarovski krai), and clustered singly. Therefore, anadromous spawning populations of species from the Japan Sea to the Suifen River actually are the southern forms of , respectively. The average genetic distance between the southern and northern forms of was 0.023, conforming to the basis of segregation of COI between groups (>0.02). We support the classification of the southern and northern forms of into two effective species or subspecies. Based on the results of the COI analysis, we speculate that hybrids of were probably produced in nature or by artificial propagation, and therefore, suggestions were proposed on how to protect and utilize the fish germplasm resources rationally.