DIVERSIDAD DE LOS NEMATODOS DE TETRA COLA ROJA ASTYANAX AFF. PARANAE (TELEOSTEI: CHARACIDAE) DE SITIOS CONTAMINADOS DE UN SISTEMA DE RÍO TROPICAL

Aquatic systems are affected by a great variety of anthropogenic activities that alter the water quality through the introduction of organic and inorganic pollutants, consequently impacting all trophic levels of a biological community. The relationship between parasite species diversity and organic pollution in the high Parana River basin, Parana, Brazil was investigated during two seasons (Winter and Summer) of 2011. A total of 114 red-tail-lambari (Astyanax aff. paranae Eigenmann, 1914) were sampled from a non-impacted location (Perobas Reserve) and from impacted regions (agricultural and urban regions, upstream and downstream the city of Campo Mourao, respectively). The nematode Spinitectus yorkei Travassos, Artigas & Pereira, 1928 was found on the preserved area, while the nematode Procamallanus (Spirocamallanus) inopinatus Travassos, Artigas & Pereira, 1928 was found only on the severely polluted areas. The variability of the prevalence index suggests that the structure of the parasite community is affected at different ways by the same levels of pollutants on the water. The observed results assume that the alteration in parasite diversity can be related to increased organic pollution, and that the differences in the parasite community from different environments can be related to biotic stress.