Remarkably Low Genetic Diversity and Shallow Population Structure Detected of the Spiny Eel (sinobdella Sinensis) in Eastern China

Background The spiny eel ( Sinobdella sinensis ) is a small subtropical fish endemic to China, Vietnam, and Laos. It has disappeared in many rivers and lakes due to anthropogenic stressors. Objective The aim of this study was to investigate the genetic diversity and population structure and to provide pertinent information of the evolutionary history and conservation of S. sinensis . Methods Mitochondrial DNA (mtDNA) cytochrome c oxidase I (COI) sequences of 144 individuals from five lakes in the Jiangsu Province of Eastern China were sequenced. Results A total of 17 haplotypes were defined by 20 variable nucleotide sites. Remarkably low haplotype and nucleotide diversity was observed in all sampled populations. The AMOVA analyses revealed that 96.44% of the genetic variation occurred within the populations. Significant genetic differentiation was detected among populations ( P < 0.05), but no large-scale regional differences were detected. Analysis of neutral evolution and mismatch distribution suggests population expansion. Low genetic diversity and shallow population structure based on COI sequences were also confirmed. Conclusions The wild resource of S. sinensis in Eastern China has sharply declined. Low genetic diversity and shallow population structure based on COI sequences were confirmed. Fishing management and resource conservation of this species should be taken urgently.