Genetic diversity, population structure, and demographic history of the chilhuil sea catfish Bagre panamensis in Northwestern Mexico inferred from mitochondrial DNA.

The chilhuil sea catfish (Bagre panamensis) is an ecologically relevant species contributing to the structure, organization, and functioning of the ecosystems it inhabits. Also, it is an important artisanal fishery resource in the Mexican Pacific coast. This study aimed to determine the genetic diversity, population structure, and historical demography of B. panamensis in the Mexican Pacific. The mitochondrial DNA was amplified from two distinct regions, r16S and COI, resulting in an 1142 bp of the concatenated genes. Low genetic diversity levels were detected for r16S (H = 12; h = 0.131; π = 0.0003) and high genetic diversity levels for COI (H = 57; h = 0.9128; π = 0.0039) and the concatenated gene fragments (H = 62; h = 0.9307; π = 0.0023). Population structure analysis indicated 'panmixia' for B. panamensis along the Mexican Pacific. Furthermore, historical demographic analysis (Tajima's D, Fu's Fs, mismatch distribution, and Bayesian Skyline plot analyses) supported a population expansion scenario for the studied species.