Brazil’s reefs are a world apart. Separated from the Caribbean by the vast freshwater and sediment plume of the Amazon, they evolved their own coral fauna and their own way of building reefs. They have fewer coral species than the Caribbean or Indo-Pacific, but a high share of those species are endemic, and the reef structures they build are unlike anything else in the Americas. This page explains where Brazil’s coral reefs are, what makes them unique, how to read the map, and the pressures they face.

Where are Brazil’s coral reefs on the map?

Brazil’s reefs fall into three groups: the Abrolhos Bank in the south, a long line of coastal reefs up the north-east, and isolated oceanic reefs far offshore.

The Abrolhos Bank, where the continental shelf widens off southern Bahia, holds Brazil’s largest and most diverse reefs. North of it, coastal reefs fringe the shore through Bahia, Sergipe, Alagoas, Pernambuco, Paraíba and Rio Grande do Norte, many of them growing on lines of beachrock and sandstone that run parallel to the coast. Famous examples include the natural pools of Porto de Galinhas and the Costa dos Corais in Alagoas and Pernambuco. Farther north, off Maranhão, the Parcel de Manuel Luís is an isolated offshore reef bank.

Far out in the Atlantic lie the oceanic reefs: Fernando de Noronha, a volcanic archipelago ringed by coral, and Rocas Atoll, the only atoll in the South Atlantic. The spread is vast, from reefs close to the Equator to others well into the subtropics.

What makes Brazil’s coral reefs unique?

Long isolation behind the Amazon plume gave Brazil endemic corals and a distinctive reef architecture.

The Amazon pours an enormous volume of fresh, muddy water into the Atlantic, creating a barrier that many reef species cannot cross. Over millions of years, that isolation let Brazilian reef life evolve separately from the Caribbean. Brazil has relatively few species of reef-building coral, but a large share are endemic. The best known are the brain corals of the genus Mussismilia, which include some of the main reef builders on the Abrolhos Bank and are considered relics of an older coral fauna. Fire corals (Millepora) are also important reef builders here.

Brazilian corals also cope with conditions that would stress many Caribbean reefs. Much of the coast receives heavy sediment from rivers, and the dominant corals tolerate turbid water well. Instead of the continuous walls and spur-and-groove reefs of the Caribbean, Abrolhos reefs often grow as chapeirões: isolated columns that rise from the seabed and spread out near the surface like giant mushrooms. Neighbouring pinnacles can merge at the top, leaving a maze of channels and caves beneath. For more on reef forms, see types of coral reefs.

The Abrolhos Bank: Brazil’s richest coral reefs

Abrolhos is the largest and most biodiverse reef complex in the South Atlantic, and home to Brazil’s first marine national park.

The Abrolhos Bank lies off the far south of Bahia, where the continental shelf extends a long way offshore. It holds a mosaic of coastal reefs, the giant chapeirões, rhodolith beds of free-living coralline algae, mangroves and a small volcanic archipelago. Abrolhos Marine National Park, created in 1983, protects the archipelago and part of the outer reefs, and a wider extractive reserve allows traditional fishing under rules.

Abrolhos is also the main breeding and calving ground for humpback whales in the western South Atlantic, usually from about July to November, and the islands host colonies of boobies, frigatebirds and tropicbirds. Turtles and endemic reef fish are common, making it Brazil’s best-known site for reef diving and whale watching.

Rocas Atoll and Fernando de Noronha

Two oceanic outposts off north-eastern Brazil, protected together as a UNESCO World Heritage Site.

Rocas Atoll is a small ring of reef and sand enclosing a shallow lagoon, built largely by coralline algae as well as coral. It is the only atoll in the South Atlantic. Declared Brazil’s first marine biological reserve in 1979, it is closed to tourism and visited only by researchers. At low tide its reef flat forms natural pools full of young fish and sharks, and its sand cays are important nesting sites for seabirds and green turtles.

Fernando de Noronha, a volcanic archipelago a little further offshore, is ringed by reefs and rocky shores in exceptionally clear water. Much of it lies within a national marine park created in 1988, and visitor numbers are controlled. It is famous for resident spinner dolphins, turtles, reef sharks and some of the best snorkelling and diving in Brazil. In 2001 Fernando de Noronha and Rocas Atoll were inscribed together as a UNESCO World Heritage Site, the Brazilian Atlantic Islands.

What is the Amazon Reef?

A deep, dimly lit reef system off the mouth of the Amazon River, described by scientists in 2016.

For a long time the muddy outflow of the Amazon was thought to rule out reefs along that part of the coast. In 2016 a team of Brazilian and international researchers reported an extensive reef system beneath the river plume, at depths of roughly 30 to more than 100 m. It is built largely by sponges, coralline algae and other organisms adapted to dim, turbid water, with some corals, and the scientists estimated it covers thousands of square kilometres.

The Amazon Reef extended the known range of Brazilian reefs far to the north and showed how much remains to be learned about the country’s seabed. It lies close to areas of interest for offshore oil exploration, which has made it a focus of conservation campaigns. Because it is deep, it does not appear on most global maps of shallow coral reefs, including the one above.

What marine life lives on Brazil’s reefs?

A mix of widespread Atlantic species and reef life found only in Brazil.

Brazil’s reef fish include many species shared with the Caribbean, along with endemics such as several Brazilian damselfish, gobies and parrotfish. Divers see groupers, snappers, angelfish, moray eels and schools of grunts, along with nurse sharks, lemon sharks around the oceanic islands, and green and hawksbill turtles. Spinner dolphins gather in their hundreds at Fernando de Noronha, and humpback whales breed around Abrolhos.

Because endemic species are found nowhere else, losing coral or fish on Brazil’s reefs means losing them from the planet. That makes protecting these reefs important on a global scale, not just a national one.

Threats to Brazil’s coral reefs

Warming seas, coastal development, pollution and fishing all press on Brazil’s reefs, and offshore oil is a growing concern.

Marine heatwaves have caused coral bleaching on the Abrolhos Bank and along the north-eastern coast, and recent global bleaching events have hit Brazilian reefs too. Nearshore reefs face coastal development, untreated sewage, sediment from deforested river catchments, trampling by visitors at popular tide pools, and overfishing. Oil spills are another risk: in 2019 crude oil washed ashore along thousands of kilometres of the north-eastern coast, reaching reefs and mangroves.

Brazil protects many of its finest reefs, including Abrolhos, Rocas Atoll and Fernando de Noronha, as well as the large Costa dos Corais protected area. Their isolation and protection have helped, but warming is a threat no reserve can stop. Explore the wider picture in our coral reef conservation pages and compare Brazil with its neighbours, Venezuela and Colombia.

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