Divergência espacial da fauna de parasitos de Hoplias malabaricus (Characiformes, Erythrinidae) em dois corpos d’água interiores do Recôncavo da Bahia

Abstract

The trahira, Hoplias malabaricus, is a common fish in freshwater. The genus comprises 12 valid species occurring in 15 countries, being in most of the hydrographic basins of South and Central America. They are carnivorous, which feed on fish small invertebrates such as shrimp, depending on supply in the environment. Thirty-five specimens from the Pedra do Cavalo Hydroelectric Power Station Reservoir, Cabaceiras do Paraguaçu city and 10 specimens from Jaguaripe River, Nazaré city, State of Bahia, were studied aiming to verify spatial variation in parasitism indicators and some ecological descriptors of the ectoparasites and endoparasites fauna from two regions. The analyzes were carried out in the Laboratory of Ictiofauna Studies, located in the Biological Sciences Sector, at the Universidade Federal do Recôncavo of Bahia, where necropsies were performed for the collection, quantification and subsequent identification of the parasites.The numerical descriptors of parasitism (prevalence and mean intensity) and descriptors of ecological communities (richness, diversity and dominance) were calculated. The obtained values were compared statistically between the two environments studied, to verify the possible spatial divergences in the specific composition and the parasite community. The similarity between the collection points was tested through qualitative and quantitative measures, inferring the regional diversity trends and possible environmental factors influential on the fish parasite communities in the different locations. Differences were observed regarding the specific composition of the parasite fauna, observing a low qualitative similarity. Statistically significant differences in the prevalence and abundance of parasite species occurring in both sites were also detected, with the Jaguaripe River being the site of higher prevalence and intensity of the species in common. The quantitative similarity was low, showing that fish from both environments presented different opportunities of infection by the parasites. These results can be considered indicative of spatial heterogeneity in the communities of traíras parasites, that is, high regional diversity, despite low local diversities.