Considerações sobre os impactos dos represamentos na ictiofauna e medidas para sua atenuação. Um estudo de caso: reservatório de Itaipu

Abstract

Impoundment impacts on fish communities are listed and the current trends to mitigate them in Brazilian hydrelectrical companies are discussed. A case history about Itaipu reservoir is presented. The most important impact on fish fauna is the alteration in the relative abundance of the species, though the local extintion becomes relevant if the endemic degree is high. The colonization process is favorable to small species with low longetivity and high reproductive potential. Species commercially important were substituted by other less valious. The failure on the impacts mitigation is associated to their incorrect evaluation and insufficient information about the stnucture and function of the system.