Abstract

A closed, diploid and panmictic population, which is a harvestable resource having a Malthusian growth, is considered. According to their genotype and for a specific locus, it is compartmentalized in three subpopulations: two homozygotes and the heterozygote one. Under the assumption that the population is extracted by alternating closures with comparatively very short open seasons, the dynamic of the coupled genotypic frequencies of each subpopulation are modeled using an impulsive differential system. In addition, it is assumed that each genotype expresses a phenotypic characteristic that differentiates the mortality rates by catchability. Some results about the long- term genotypic distribution are obtained and presented as threshold conditions on the parameter space.