The Project
Volunteer with Pink River Dolphins in Brazil

Two unique dolphins have evolved to live exclusively in the major rivers of northern South America - the boto or Amazon river dolphin, Inia geoffrensis, and the tucuxi Sotalia fluviatilis. Both of these dolphins are fish eaters and are among the largest aquatic predators of South America. Both live abundantly in and around the Mamirauá Reserve, where our study is based.

Freshwater dolphins also occur in several more of the world’s largest river systems (Yangtze, Indus, Ganges and Brahmaputra). However, the pressure of human populations in Asia, and their destruction of riverine habitats through dams, fishing and pollution, has resulted in the dramatic decline of dolphins in these areas. Indeed, the Baiji (Yangtze river dolphin) has recently been made extinct and Bhulan (Indus river dolphin) is the most endangered dolphin in the world. Only in the Amazon and Orinoco river basins are river dolphins not currently undergoing obvious declines, and that is simply due to the fact that the human populations have not yet exploited rivers to the same extent. This is the good news. The bad news is that exploitation is currently increasing in pace, even here. Every dam, every gillnet, every mercury-laden goldmine brings nearer the day that dolphins will be as rare in the Amazon as they have become in Asia.

The project is primarily aimed at providing information and advice on which dolphin conservation can be based in Mamirauá and, more generally, in the Amazon and Orinoco basins and in Asia. We seek to revolutionise our understanding of the biology and ecology of the boto and tucuxi, identifying key habitats and the dolphin/human interactions that most threaten, and least threaten, the populations of these animals.

The project has the following objectives:

1. 1) To establish the number of dolphins of the two species that use the Mamirauá reserve and its surrounding rivers
2. 2) To monitor these populations in relation to changing management regimes within the reserve
3. 3) To investigate the impact of various types of fishing on dolphins, especially in relation to entrapment and drowning
4. 4) To investigate the impact on dolphins of ecotourism and other human activities in this region
5. 5) To establish the relative use of the different habitats in this area, and their importance to each dolphin species
6. 6) To determine basic population parameters, such as age at first reproduction, inter-birth interval, and age-related survival
7. 7) To determine the social and mating organisation of the two species
8. 8) To investigate the health of Mamirauá’s dolphins and their exposure to disease
9. 9) To provide advice to legislators and managers at local, state and national level, on what measures must be taken to prevent the decline and ultimate loss of river dolphins in South America
10. 10) To train bright young scientists, volunteers and local managers in the use of appropriate techniques and technology to increase the knowledge and conservation status of fresh water dolphins
11. 11) To educate the local people of the Mamirauá area about the importance of environmental care and sustainable resource use, and in the value of maintaining a world in which both they and dolphins can live together.



The project has been underway at the current level of activity for several years now, and we have a number of achievements under our belt. These include the publication of four papers in international scientific journals, and the presentation of seven talks at large international conferences. To date, more than 30 young scientists from seven countries have been trained in dolphin research techniques, and in so doing have contributed to our vast database. This now includes more than 25,000 observations of known dolphins!

Our most exciting achievement is surely the development of the pool of marked and recognisable animals that form the backbone of this study and the research techniques that allow us to learn so much from them. It is the daily discoveries that come from many long hours on the water, binoculars in hand, that make this work so special. And this is exactly where volunteers can help - contributing their eyes, data entry fingers and financial resources to keep this unique project pushing forward.