Parasites of Astyanax bockmanni collected from the Batalha River, São Paulo State, Brazil

Resumo

Astyanax bockmanni Vari e Castro, 2007 also popularly know as lambari-do-rabo-vermelho, is a fish belonging to the Characiformes order and Characidae family and endemic of the Upper Paraná River Basin, occurring throughout its length. The Batalha River is an important source for the urban water supply of the city of Bauru-SP and over the past few years has been the target of constant anthropic aggression. Thus, the study of parasites of fishes is of great importance for the understanding of ecosystem functioning and generate of subsidies for the conservation of degraded aquatic environments. Studies related to natural parasite fauna of fishes of the Tietê-Batalha river basin in the State of São Paulo are scarce. Here, we conducted a survey and identification of parasitic fauna of A. bockmanni. The fish samples were taken in the water catchment lagoon of the Batalha River, located in the city of Piratininga, State of São Paulo, between August 2013 and July 2014. A total of 19 specimens were analyzed. After collected, the fish were necropsied and the external surface and other internal organs were individually analyzed with stereomicroscope for the collection of parasites. The most commom sites of infestation/infection were the gills, the body surface and intestine. In total eight species were identified: Henneguya sp. (Myxozoa), Cacatuocotyle guaibensis, Characithecium sp., Diaphorocleidus sp.1, Diaphorocleidus sp.2 e Gyrodactylus sp. (Monogenea), Bacciger delvalleensis (Digenea) e Contracaecum sp. (Nematoda). The prevalence of the parasites varied between 5% e 26%, while the intensity and average abundance varied between 0,2 e 1,0 e 1,0 e 3,0 respectively.  The majority of found parasites have a direct life cycle and the gregarious habits of the hosts may favour this parasitism. This is the first record of all these parasites for A. bockmanni and also to this locality.