By Rodrigo Leitão, environmental lawyer and member of the Pororoka Colective and Alexandre Anderson, of the Ahomar Network.

Guanabara Bay, in the state of Rio de Janeiro, knows all too well what the arrival of the oil industry means. This history began in 1954, when the Manguinhos Refinery began operating. Then, in 1961, came the Duque de Caxias Refinery, REDUC. Then came pipelines, terminals, petrochemical facilities, offshore industry support structures, vessels and new installations followed. Decade after decade, the industry occupied the Bay, competing for space with those who had already lived there.

Separate licenses, cumulative impacts

In Guanabara Bay, the destruction caused by the oil industry did not happen all at once. Each project had its own licensing process. Evaluated separately, the full picture of the impacts was never seen — or perhaps never wanted to be seen. By the time the problems became visible, much had already been lost.

In January 2000, the rupture of a REDUC pipeline spilled approximately 1.3 million liters of oil into Guanabara Bay. Mangroves, beaches, fish, birds and thousands of fishermen were affected. But the violence against artisanal fishing did not begin at that moment. It had already been taking place through the reduction of fishing grounds, exclusion zones, the traffic of large vessels, dredging, pollution and the progressive transformation of the territory.

The spill of more than 1 million liters of oil into Guanabara Bay in January 2000 has severely affected a large part of the region's wildlife. Credit: Reproduction/Museu do Amanhã

A participatory mapping project carried out with artisanal fishermen from Guanabara Bay showed the scale of this loss. A study by Carla Ramôa Chaves, developed at the Federal University of Rio de Janeiro (UFRJ), found that only between 12% and 25% of the Bay's area remained free of restrictions on fishing. The oil industry emerged as the largest user of the water surface.

The impacts of oil exploration in Guanabara Bay have fueled the territorial dispute between oil companies and artisanal fishermen. Credit: Custodio Coimbra

Territory and life

Losing fishing territory means much more than losing an area on a map. Territory means income, food, knowledge and spirituality. The very definition used by the Brazilian Federal Government recognizes that life in these communities is organized around the waters and their cycles. It took many generations to learn the right time to take from nature what it offers us. But for that to continue, fishermen depend on mangroves, rivers, estuaries and seas remaining alive.

That is why, when a fishing territory disappears, it is not merely an economic activity that disappears — an activity that, as many people think, could easily be replaced by another source of income. It is violence because it annihilates a way of life passed down from parent to child, forged through collective experience and respect for nature. It is violence because something that people have learned to love and value is destroyed in the name of a model of development that never arrived and never will.

It is impossible to look at this history and not think about the Amazon River Mouth.

Block 59 is only the beginning

On August 14, Petrobras confirmed that it had found oil in the main well of Block FZA-M-59. As soon as the news broke, several foreign oil companies requested permission to drill in the area. The block, with four drilling wells planned, may be presented as an isolated project 175 kilometers off the coast of Amapá, but we are not talking about just one project.

In 2025, contracts were signed for 19 new blocks in the Amazon River Mouth Basin, and in June 2026, the National Agency of Petroleum, Natural Gas and Biofuels (ANP) identified another 36 blocks in the same basin for study, with a view to including them in future bidding rounds. These facts show that we are witnessing the opening of a new frontier for oil industry exploration.

With the beginning of production will also come support vessels, shuttle tankers, helicopters, subsea structures, safety zones, logistics bases, port facilities, fuel, waste, workers, storage facilities, pipelines and terminals.

That is how the invasion of Guanabara Bay grew, little by little, until it ceased to be merely a collection of projects and became a permanent dispute over territory.

Fishermen in the Amazon River Mouth Basin do not need to wait twenty or thirty years to discover what the fishermen of Guanabara have learned over the course of their own lives: oil does not occupy only the seabed; it invades living territories and destroys them.

A mangrove belt that surrounds the planet

Unlike the generations that came before us, the greatest challenge of our time is not to control nature, but to join forces with it if we want any chance of surviving climate change. In the world's perfect and delicate balance, mangroves play a key role: they are important carbon sinks, absorbing one of the gases responsible for global warming. At the Amazon River Mouth lies the largest mangrove belt on the planet and the largest share of Brazil's mangroves, extending across the states of Amapá, Pará and Maranhão.

The Amazon river mouth is home to one of the largest mangrove belts in the world. This biome is fundamental in capturing carbon and in the fight against climate change. Credit: Enrico Marone/Greenpeace

Mangroves are also fundamentally important to local life, serving as nurseries for countless marine species that provide food and income for traditional communities — something already recognized by Brazil's Ministry of the Environment. IBAMA has also classified the region as an area of extreme socio-environmental sensitivity, highlighting Indigenous Lands and Conservation Units that protect peoples, threatened species and one of the greatest known concentrations of biodiversity.

IBAMA has also warned, however, that assessing an isolated project, such as Block 59, does not answer the question of whether the region is suitable to host the entire oil production chain.

“May strong winds blow in Guanabara Bay”

This is the motto of the Association of Men and Women of the Sea of Guanabara Bay. A kind of omen that precedes a great victory. The AHOMAR Network, founded in 2007, now brings together 11 associations and around four thousand fishermen who fight for the regularization of community territories and against the progressive loss of fishing territories in Guanabara Bay. The group resists chronic pollution, pressures arising from REDUC's operations and the logistical expansion associated with the COMPERJ — Rio de Janeiro Petrochemical Complex — project, confronting serious socio-environmental conflicts and threats against fishermen.

Alexandre Anderson, fisherman and president of the Association of Men and Women of the Sea of Guanabara Bay, has a whole life dedicated to the work in defense of artisanal fishing in the Guanabara Bay. Credit: Reproduction

The experience of Guanabara can help strengthen a broad alliance of artisanal fishing communities in the Amazon River Mouth Basin to map fishing territories, document traditional fishing grounds and routes, monitor changes in the quantity and quality of fish, track impacts, produce information through the communities themselves, and fight to ensure that people have a voice before decisions are made — not only after impacts and damage have occurred.

It means fighting to ensure that an economy that may last a few decades does not destroy a socio-bioeconomy that has sustained generations and could sustain many more.

May strong winds blow in Guanabara Bay, and may those winds reach the peoples of the Amazon River Mouth.