Population structure and beak shape variation in Octopus hubbsorum (Berry, 1953) inferred from microsatellite markers and geometric morphometry in the Mexican Pacific

Octopus hubbsorum (Berry, 1953) is the most commercially important species in the Mexican Pacific; however, its population aspects and biology have rarely been addressed. It is a benthic species inhabiting rocky and sandy substrates in inter- and subtidal zones. Although some studies have addressed issues related to the life history of O. hubbsorum, little is known about the identification of discrete stocks or populations. The aim of this work was to compare the population structure of the octopus Octopus hubbsorum inferred from microsatellite markers and beak morphometric analysis in the Mexican Pacific. The diversity and population genetic structure of Octopus hubbsorum were inferred using microsatellite-type molecular markers for locations in the Mexican Pacific. Morphological analysis was based on geometric morphometrics of the upper beaks. All the loci were polymorphic, and the genetic diversity was relatively high. Our analysis indicated that the localities do not present significant levels of kinship. With respect to genetic differentiation between populations, the values of F_ST showed evidence of moderate to high differentiation, and Bayesian analysis revealed at least six well-defined populations on the basis of the ADMIXTURE and NO ADMIXTURE models. Principal Components Analysis also suggested the presence of differentiated groups. Geometric morphometric results of the upper beaks also provided compelling evidence of morphological differentiation between the localities. Based on our results, Octopus hubbsorum has a well-defined population in the Mexican Pacific. This understanding can guide the development of targeted conservation and sustainable exploitation strategies.