Freshwater fishes of South America: their biodiversity, fisheries, and habitats a synthesis

Over long geological time periods, South America offered a large variety of waterbodies and habitats to aquatic organisms. Large river systems and streams of different water quality, different types of wetlands and high-altitude lakes favoured the development of a species-rich fish fauna with a large variety of adaptations. Therefore, South America is today a centre of megadiversity of fishes. In large areas, aquatic habitat health is still intact but environmental degradation is accelerating with negative impacts on the fish fauna. Inland fisheries are of great importance for protein supply of the local population, but stocks are already depleted in some areas. Fish culture is becoming increasingly important to supplement decreasing catches but cannot prevent loss of biodiversity. Lack of knowledge about fishes and their habitats, inefficient management of aquatic resources, large-scale uncoordinated modification of catchment areas, and the low priority given by the governments to fisheries and the protection of aquatic and wetland systems are reasons for decreasing fish stocks, deterioration of aquatic habitat health, and decreasing species numbers. A summary of the status of fish biodiversity, fishery, fish culture and habitat health in major South American rivers systems, the Altiplano and Patagonia is provided and the possibilities for sustainable management of aquatic resources and the protection of fish biodiversity are discussed