Hidroelectric Energy and River Dolphins in Western Amazon

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As inhabitants of the most complexes river basis of the world, river dolphins are directly and indirectly affected by dam projects. Under intense pressure, many species are mentioned by IUCN (International Union for Conservation of Nature) red list at some level of threat. The possible extinction of the Yangtze River Dolphin (Lipotes vexillifer), highlights the urgency of understanding the vulnerability and resilience of freshwater cetaceans in response to impacts on their habitat and particularly impacts caused by dam constructions.

With water and energy demand growing side-by-side with population size and impacts of global climate change escalating, decision-makers seek to consider dams and hydroelectric energy one key solution to account for many issues of humanity development. Therefore, dam construction programs have being implemented around the world, especially in developing countries. The Amazon river dolphin (Inia sp.) is distributed throughout the Amazon and Orinoco river basins, areas with high hydraulic potential that has been explored for decades.

Most deleterious effects in freshwater habitats, caused by dam construction may include habitat fragmentation, temporal and physical changes in hydrological cycle and complexity, among others. All disturbances will affect habitat use of most species in many aspects as well as may reduce access to sources of food and protection, split populations, generate pollution, increase stress and disease vulnerability. In addition, those impacts may also interact with incidental catches, impacts of irrigation projects and other sources of environmental changes, amplifying the negative effects on riverine cetacean populations.

Dam's impacts are a real threat to river cetaceans around the world and it has already contributed to population decline of several species. Unless appropriate measures are put in place, it is not unlikely that cetacean’s extinctions will be accelerated by habitat changes caused by it. Moreover, it is necessary to consider all the options and impacts assessments including cumulative assessments of planned dams on river basin and developing tools to assess this information, avoid and mitigate with a certain degree of standardization. Studies pre, during and post constructions are fundamental in order to monitor impacts on physical and biotic elements of the environment. 

The Cetacean Society International (CSI) supported this study for theme propagation and awareness of hydroelectric dams impacts on cetacean populations at international meeting for aquatic mammal experts.