Integrating parasite assemblages and host genetics for population discrimination in the black grouper (Mycteroperca bonaci) in natural protected areas of the northern Yucatan peninsula

Abstract

The population structure of the black grouper (Mycteroperca bonaci) from the northern Yucatan Peninsula was evaluated with a two-fold emphasis on the spatial scales (whether island or coastal localities), as well as the effects of protection based on three natural protected areas (NPA) with different categories. To this end, specimens were collected at each NPA: Celestun (Biosphere Reserve) and Dzilam (State NPA) which are coastal and Alacranes (National Park) which is an island. Population discrimination was carried out by means of intestinal helminth parasite infracommunities and the hosts’ genetic similarities, highlighting the contradictions or coincidences between approaches. The intestinal parasitic fauna was examined in 161 specimens, of which 150 were genetically characterized using microsatellite DNA markers. Three distinct parasite communities were observed, in which taxa mainly responsible for the differences were the digeneans Prosorhynchus atlanticus, Prosorhynchus sp., Lepidapedoides epinepheli and Hamacreadium mutabile as well as the acanthocephalan Gorgorhynchus sp. The hosts’ genotypes indicated three genetically separated subunits that deviated significantly from Hardy–Weinberg equilibrium, and genetic differences evidenced a structured population. Despite the expectation that island NPAs would be distinctive, the coastal locality of Dzilam was the most differentiated. The present recognition of population subunits would indicate the beneficial effects of preserving the gene pool variability of the coastal Dzilam subunit since it is, at present, the least restrictive NPA where unregulated fishing is still allowed. Thus, this study indicates fishing regulations should be strengthened (e.g. determine catch quotas or reduce fishing effort) to prevent diversity loss (whether biological or genetic) in these NPAs, particularly in Dzilam, which is probably the most threatened area.