Abstract

South America boasts an enormous diversity of aquatic species distributed along thousands of miles of coastline ranging over a vast latitudinal gradient from the tropics to sub-Antarctic waters, including massive freshwater ecosystems. The Amazon River is the world's largest river basin, accounting for approximately one-sixth of the fresh water flowing into the world's oceans and sustaining more than 3,000 species of fish and other wildlife. In an attempt to appropriately identify the main health threats for aquatic species in S. America, local scientists were consulted and a literature review was performed. Based on responses from twelve scientists involved in freshwater and marine species conservation and literature reports, the major threat categories identified include freshwater ecosystems and species: infrastructure development, specially dams, hydrocarbons and mining, and their associated deforestation and agriculture expansion which results in water pollution, soil erosion, increased sedimentation and reduced biodiversity in the rivers. Water pollution from the indiscriminate use of agricultural pesticides, control of illicit crops, dumping of solid wastes, illegal gold mining, and inadequate water use and wastewater treatment from populated areas is also significant. Increased boat traffic in rivers resulting in direct mortality or behavioral changes in some species, introduction of exotic species, and overharvesting for the illegal wildlife trade (e.g. ornamental fish, turtles) and human consumption (e.g. fish, turtles, caiman, dolphins) were also highlighted. Changes in hydrological cycles associated with global climate change are also considered important current and upcoming threats for the health of aquatic ecosystems of the Amazon. For marine species and coastal ecosystems, the threats include interaction with fisheries (bycatch and prey competition) resulting in direct mortality and leading to impoverished condition and disease (particularly in small cetaceans, seabirds and sea turtles); direct and indirect health impacts of pollution from offshore gas and oil drilling and transportation as well as from aquaculture (i.e. antibiotics, antifouling products), infectious diseases (particularly skin disease in cetaceans, malaria in penguins); ingestion of solid human waste (i.e. plastics in sea turtles and seabirds); and unidentified causes of mortality such as penguin feather loss disorder and ongoing southern right whale mass mortalities at Peninsula Valdes. Coastal development, tourism, and climate change are also expected to have on impact on coastal breeding species. A summary of the most critical health threats affecting specific species and areas will be presented for discussion, focusing on a few examples of special concern.

Acknowledgements

The author wishes to thank Virginia Rago for reviewing the literature and compiling information, and the scientists who contributed information and insights: Diego Albareda, Adriana Burbano, Victoria Gonzalez Carman, Claudio Campagna, Karl Didier, Padu Franco, Barbara Galletti, Katia and Karina Groch, Milton Marcondes, Martin Mendez, Patricia Mendoza, Flavio Quintana, Valeria Ruoppolo, Mariano Sironi, Diego Soler-Tovar, Ralph Vanstreels, and Robert Wallace.

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