Variação espacial da fauna parasitária de Chaetodipterus faber (Broussonet, 1782) (Perciformes, Ephippidae) em dois rios da bacia hidrográfica do Recôncavo Sul, Bahia

Abstract

Chaetodipetus faber (Broussonet, 1782) (Teleostei: Ephippidae), popularly known as Atlantic spadefish, is an estuarine fish commercially attractive due its good quality of meat, also serving as ornamental fish. It is the only representative species of the Ephippidae family in Brazilian territory. Fifteen specimens from the Una River and fourteen specimens from the Jaguaripe River, Recôncavo Sul Basin, Bahia, were studied. This paper aim to study the spatial variations in the ectoparasites and endoparasites communities, and was carried out in the Laboratório de Estudos da Ictiofauna, located in the Setor de Ciências Biológicas Professor Elinsmar Adorno, in Universidade Federal do Recôncavo da Bahia. The fish had the specific identity confirmed and were necropsied for the parasites. The parasites were prepared according to conventional techniques of ichthyoparasitology and identified according to specialized bibliography. After quantification of each species of parasite, the infection indexes (prevalence, mean intensity and average abundance) and ecology community descriptors were computed at the component community and infracommunities levels (diversity, wealth and dominance). These were compared statistically between the two environments, aiming to verify possible spatial variation in the specific composition and structure of parasitic communities and infracommunities. Significant differences were observed in the infection levels of some parasites in the two environments studied, which should probably be related to both biotic conditions (differentiated availability of intermediate hosts) and abiotic conditions (physical and chemical parameters, hydrology, pollution and others) differences. The qualitative similarity was high (60.8%), which may be an indicator of low regional diversity, since the two basins are spatially distinct and, even so, the species found in the parasite community are mostly the same. Quantitatively the similarity was low (19%), showing that the environments should have factors that influence the amount of parasites that access the hosts, probably related to anthropization.