The large pirarucu (Brazil) or paiche (Peru) is one of the largest freshwater fish in the world and a prized food fish. It is also one of the main predators in floodplain lakes where the species has not been overexploited.

Working Group:
Amazon Waters

Our focus: how to ensure a new understanding of the Amazon Basin, in which the region is recognized and valued not just for its rich tropical forests and its importance for carbon storage, but for its role as the world’s greatest and most diverse freshwater system.

Photo: Michael Goulding | More Info
Photo: Schristia


Amazon Waters: Maintaining Connectivity of Amazonian Aquatic Ecosystems for Human Well-Being and Diversity

The Amazon Basin is the largest tropical wilderness area in the world, the most biologically diverse place on Earth, and home to hundreds of indigenous peoples and other traditional cultures. It is also the greatest freshwater system in the world, accounting for 15 percent of the freshwater discharge into global oceans — six times larger than the second most important system (which is the Congo River).

Yet when most people think of the Amazon, they envision the great terra firme forest threatened by colonization, roads, cattle ranches, and plantations, and the global consequences of their loss and degradation. Rarely do non-Amazonian people visualize this immense system from the perspective of water flowing through it.

Once thought to cover a mere 4 percent of the Amazon, our science now shows that flooded forests, rivers, lakes and other wetlands cover a vast 14 percent of the basin. These aquatic ecosystems are foundations of life in Amazonia, critical not only to biodiversity but also for sustaining major fisheries and transportation industries and providing water and other aquatic resources for 30 million Amazonian residents, including 1.4 million indigenous people.

How can connectivity of this vast, interlinked, and dynamic freshwater system be maintained, to support human well-being, wildlife, and the environments on which they depend? This will require the conservation of critical wetlands, strengthening fisheries management, and minimizing the environmental impacts of infrastructure and extractive industries on the Amazon’s diverse aquatic ecosystems.

The SNAPP Amazon Waters Working Group has developed a strong scientific foundation to support this vision, and we are now in a position to suggest management and policy pathways for large-scale aquatic conservation. These efforts need to be based on integrated river basin management.

Understand the Challenge

Photo: Michael Goulding

The Challenge

Integrated River Basin Management: Key to a Balanced Conservation and Development Strategy

The Amazon’s highly productive and immensely valuable wetland ecosystems are under threat for three primary reasons.

First, the highly productive fisheries of the Basin are not managed at the appropriate scale. Eighty percent of fish landings are migratory species whose life history takes them between various sub-basins and countries and, in some cases, from the Amazon River estuary to Andean headwaters more than 4,000 km upstream. Yet no fisheries management system operates at a basin-wide scale, and unsustainable commercial and subsistence fishing is the norm.

Second, infrastructure development, including hydroelectric dams, roads, waterways and the infrastructure of mining and oil and gas extraction, risk altering normal flood regimes and the flow of critical nutrients and sediments across the entire basin. These flows are essential to the productivity of wetland forests and the fish and other animals that feed in them during high water periods. They are also essential to wild fruit production, floodplain agriculture, river transport and to human settlements in wetlands.

Third, climate change is and will affect the Amazon’s seasonal flood cycle. Climate change models indicate that these changes will augment the well-known risks of deforestation and land cover change. Together with infrastructure, these impacts are likely to exacerbate more extreme and less predictable flood pulses that would impact wetland habitats, fish migrations, and aquatic biodiversity. As many as 500,000 rural people actually live in wetland areas that would be directly affected by these major hydrological changes, in addition to the millions of urban residents whose livelihoods depend less directly on the great river system.

The vast size of the Amazon Basin, the interlocking relationships among uplands and wetlands, and the flow of water through wetlands from the Andes to the Atlantic strongly suggest that, to be effective, conservation actions must be informed by scientific analysis and synthesis of information at large enough scales as to be capable of capturing these ecological complexities. One of the principal telltales of the complex processes involved and their far-flung scale is fish migrations, where hydrological cycles, water quality and quantity and regional weather patterns influence the reproductive success of these valuable species.

Conservation approaches today in the Amazon Basin focus on creating and strengthening protected areas and indigenous territories. A half century of such efforts have been vital to secure forested landscapes and provide tenure and access to resources for indigenous peoples, but they have done little to protect the Basin’s aquatic systems, provide for the long-term sustainability of their natural resources, or ensure Basin-wide connectivity. Focusing now on interventions that address these issues is critical.

Read About the Inquiry

Aerial view of the Amazon Rainforest, near Manaus, the capital of the Brazilian state of Amazonas.

The Inquiry

Amazon Waters: Activities & Products of the Working Group

Critical Goals

  1. The Working Group will analyze available data on waters, wetlands and fisheries in relation to present and expected wetland resource use, infrastructure development, and possible climate change.
  2. The analyses will be used to construct science-based syntheses at an unprecedented spatial scale that captures the complexity and interconnectivity of Amazonian wetlands and their critically important migratory and non-migratory fishes.
  3. These syntheses will be used to develop different scenarios of integrated river basin management.
  4. The Working Group will use the analyses to develop scenarios on how predicted changes to wetlands and fisheries could impact urban and rural populations in the western Amazon.
  5. The Working Group will then bring together government personnel, project investors, scientists, NGOs, and local associations concerned with aquatic resources to examine and fine-tune the recommendations and potential tradeoffs associated with each proposed integrated river basin management scenario.

Critical Questions and Activities

  1. Where are the highest conservation value areas (HCVA) for migratory fish? Using a series of GIS analyses, we will map and quantify the spawning, nursery and feeding wetlands most important to commercial migratory species and some of the non-migratory species valued locally. The analyses will be presented in relation to sub-basins, political units and protected areas to build a geographically dynamic view of the distribution of HCVAs. We will suggest realistic, space-based frameworks for the management of the wetlands and fisheries.
  2. What environmental changes can be expected to impact migratory fish populations? We will focus mainly on the potential impacts of planned dams, artificial waterways (hidrovias), hydrocarbon exploitation and deforestation associated with roads and agricultural expansion in the Andes-Amazon headwater basins and the western lowlands. Analyses will include potential downstream impacts on river flow, sediments and nutrients and, in turn, their potential impacts on wetlands and migratory and non-migratory fishes of subsistence and commercial importance.
  3. How will climate change affect the seasonal flood and drought cycle of the Amazon? Using existing South American climate models with specific Amazonian data and/or assumptions along with historical meteorological data, we will be able to better understand and perhaps predict expected flood and low water extremes that could impact wetlands, fisheries and rural and urban settlements.
  4. How will people be impacted by changes to wetlands and fisheries? Using existing data and expert opinions, we will assess the potential impacts of the scenarios outlined above on the lives of the Amazon people. Indicators will include demographics, food consumption and protein, income, employment and cultural values related to wetlands and fisheries in various sub-basins and political units.
  5. Based on the analyses from Questions 1-4, what are the key policy and management recommendations? Policy and management recommendations will be developed incrementally as our analyses unfold. These recommendations will be improved with the review and feedback from various critical stakeholders as the project progresses.

Preliminary Results

The working group’s multinational, multidisciplinary, and multi-institutional team of scientists has developed a new scientific understanding of the Amazon based in an unprecedented basin-wide analysis of freshwater ecosystems. Among the principal findings are:

  • Flooded forests, rivers, lakes and other wetlands cover 14 percent of the Amazon Basin, not 4 percent as previously thought.
  • The Amazon River Main Stem — the downstream segment or artery that receives water from its main tributaries — is itself a critical ecological unit that requires explicit management.
  • The confluence of nutrient-rich rivers (whitewater rivers) and nutrient-poor rivers (blackwater and clearwater rivers) are important spawning nodes in the life cycles of migratory fish and are priorities for management and conservation efforts.
  • Mapping of the life cycles of 30 of the most commercially utilized fish species shows that, overwhelmingly, migratory species are the most important.
  • Andean dams in the northwestern Amazon would have far more devastating impacts than those of the southeastern Amazon. Models of the potential impacts of the proposed six largest dams in the Andean headwaters suggest that the flow of sediments that nourish the freshwater system would decrease 71 percent, and the flow of phosphorus and nitrogen would decrease 51 percent and 24 percent, respectively.
  • Climate models show that significant hydrological changes related to climate change can be expected in the Amazon Basin in this century. These changes include wetter conditions in the western Amazon and drier conditions in the eastern basin, particularly increased river discharge in the western Amazon and decreased river discharge in eastern basins. The initial modeling results also strongly suggest that synergies with infrastructure could exacerbate impacts in the western Amazon.
  • In the western Amazon alone, over half a million people live in or near wetlands and depend directly on the natural resources they provide. These include fish, the major source of protein for these populations, whose per capita consumption averages 30kg/year.

The Amazon Waters website,, launched in September in Spanish, Portuguese, and English and serves as a repository of data, tools, maps, images and publications, and as a collaborative space for engagement in this effort.

Among the tools that the working group has developed is the first framework for integrated river basin management available across the entire Amazon Basin. It includes a scalable GIS basin classification up to seven sub-basin levels, enabling spatially explicit analysis, management, and monitoring to be implemented at varying scales (depending on need) within a single integrated framework.

It also cements the concept of the Amazon River Main Stem as a management unit. Upcoming scientific publications will address long-distance fish migration, integrated river basin management, potential impacts of Andean dams, climate change and predicted hydrological changes, and the aforementioned spatial framework for analyzing and monitoring Amazon aquatic ecosystems.

In the coming weeks and months, we will develop scenarios and discuss management recommendations to inform critical stakeholders on urgent steps needed to ensure the integrity of this vast and interconnected river system. These recommendations will include steps to strengthen fisheries management in the Amazon River Main Stem and priority sub-basins, measures to ensure critical Amazonian wetlands are well-managed; and frameworks to minimize the environmental impacts of infrastructure and extractive industries on the Amazon’s aquatic systems

Download final product report, An explicit GIS-based river basin framework for aquatic ecosystem conservation in the Amazon.

Access the Amazon GIS-Based River Basin Framework as an ESRI geodatabase.

Visit the Amazon Waters Initiative website for access to data, tools, maps, images and publications related to the effort.

Read the SNAPP blog post: New Roadmap for Guiding Development and Freshwater Conservation Efforts in the Amazon.

Read the NCEAS Announcement about recent working group findings: Dorado Catfish Crowned Longest Freshwater Migratory Fish

Meet the Team

Photo: Neil Palmer (CIAT) | More Info

The Team

The Amazon Waters Team

Carlos Durigan

Wildlife Conservation Society-Brazil, Country Director

Jane “Carter” Ingram

Ernst & Young

Paulo Petry

The Nature Conservancy

Armando Mercado

Wildlife Conservation Society-Peru

Bruce Forsberg

Instituto Nacional de Pesquisas de Amazonia-Brazil

Urbano L. Silva, Jr.

Instituto Chico Mendes de Conservacao da Bioversidade-Brazil

Carlos Canas

Wildlife Conservation Society-Peru

Eduardo Venticinque

Universidade Federal do Rio Grande do Norte-Brazil

Guillermo Estupinan

Wildlife Conservation Society-Brazil

Manuel Glave

Group for the Analysis of Development-Peru

Oriana Trindade de Almeida

Universidade Federal do Para-Brazil

Sergio Luiz de Medeiros Rivero

Universidade Federal do Para-Brazil

Charles Jones

University of California-Santa Barbara

Ed Beighley

Northeastern University

John Melack

University of California-Santa Barbara

Leila Carvalho

University of California-Santa Barbara

Marcos Costa

Universidade Federal de Vicosa-Brazil

Mino Viana Sorribos

Universidade Federal do Rio Grande do Sul-Brazil

Rodrigo Cauduro Dias de Paiva

Universidade Federal do Rio Grande do Sul-Brazil

Leandro Castello

Virginia Polytechnic Institute and State University

Miguel Angel La Rosa Salazar

Instituto de Estudios Peruanos-Peru

Flavio Bezerra Bazos

Universidade Federal do Pará-Brazil

Edna Alencar

Universidade Federal do Pará-Brazil

Marcelo Paustein Moreira

Fundação Vitória Amazônica-Brazil

Polliana Ferraz

Instituto Mamirauá-Brazil

Efrem Ferreira

Instituto Nacional de Pesquisas da Amazonia-Brazil

Rosseval Galdino Leite

Instituto Nacional de Pesquisas da Amazonia-Brazil