Genetic diversity and relatedness inferred from microsatellite loci as a tool for broodstock management of fine flounder Paralichthys adspersus

Abstract

Paralichthys adspersus is a native species from the Pacific coast of South America that is of great economic importance for Peruvian aquaculture. Even though establishing sustainable farming depends on avoiding irreversible damage to the population gene pool due to processes such as inbreeding, studies focusing on genetically characterizing farmed stocks are yet to be documented. By using ten microsatellite loci on captive and wild individuals of P. adspersus, we successfully characterized the only commercial broodstock of this species in Peru by means of determining the genetic diversity and inferring relatedness. Although most microsatellite loci showed deviations from Hardy-Weinberg equilibrium, the genetic diversity levels in the commercial broodstock were considered healthy compared to those obtained for a wild population, with an average number of alleles of 17.40, an effective number of alleles of 9.14, and an observed and expected heterozygosity of 0.49 and 0.87. No significant differences between the broodstock and the wild population in terms of genetic diversity were observed. The fixation index and analysis of molecular variance also indicated a low rate of differentiation between both populations. In relatedness estimation, the analysis based on five method-of-moment estimators and a maximum-likelihood estimator showed the category “unrelated” as being the most probable relationship among the individuals within the commercial broodstock. Our findings reveal the conservation of genetic diversity in this population and outline potential breeding strategies that hatchery managers could use to minimize the loss of genetic diversity and long-term inbreeding. This could help establish proper genetic management in captive populations of P. adspersus and should apply to other captive stocks where pedigree information is lacking.