Abstract
Liobagrus geumgangensis is a novel Korean fish species endemic to the Geumgang and Mangyeonggang River basins on the Korean Peninsula. During a survey of L. geumgangensis, the discovery of Liobagrus mediadiposalis as a potential threat prompted an investigation into L. geumgangensis genetic diversity and structure. Three populations of L. geumagangensis and one population of L. mediadiposalis were investigated using a 1024-bp sequence in the cytb region of mitochondrial DNA. The Mangyeonggang River of L. geumagangensis displayed the lowest haplotype diversity (Hd) within a range of 0.000–0.337, with one to two haplotypes (h). The Jecheon region of the Geumgang River for L. geumagangensis population had the highest nucleotide diversity (π) and was within the range of 0.00000–0.00066. The h of L. mediadiposalis population was 3, the range of Hd was 0.292, and π was 0.00231. Tajima’s D (D) and Fu’s Fs (F) were negative and non-significant in the LgGJ population. The genetic structure of L. geumgangensis had no shared haplotypes among the three populations. The discovery of L. mediadiposalis in the Geumgang River suggests the necessity of non-habitat conservation and population management of fish farms to conserve L. geumgangensis.