Guadeloupe packs two very different islands, a barrier-reef lagoon and a cluster of smaller islands into a compact archipelago. That variety shows up underwater: steep volcanic slopes on one side, shallow limestone shelf on the other, and between them one of the most important reef and mangrove systems in the Lesser Antilles. This page maps where Guadeloupe’s coral reefs are, explains why they look so different from one wing of the butterfly to the other, and covers the pressures they face.

Guadeloupe coral reef map

Reef rings much of the archipelago, with a long barrier reef closing off the bay between the two main islands.

On the map, the most striking feature is the line of reef stretching across the mouth of the Grand Cul-de-Sac Marin, the broad bay on the north side of the archipelago where Basse-Terre and Grande-Terre meet. Behind it lies a sheltered lagoon. Elsewhere, shading fringes much of Grande-Terre’s south and east coasts and the shores of the smaller islands, while on high, volcanic Basse-Terre reef is more patchy and confined to sheltered stretches of the Caribbean (leeward) coast, including the area around the Pigeon Islets.

The reef outlines are taken from the UNEP-WCMC global warm-water coral reef dataset, compiled from satellite imagery and field surveys. Shading shows the mapped extent of reef structure rather than live coral cover. It is a guide to where reefs are, not a navigation chart; the reefs of the Grand Cul-de-Sac Marin and around Grande-Terre are shallow and catch boats every year.

The Grand Cul-de-Sac Marin barrier reef and lagoon

One of the longest barrier reefs in the Lesser Antilles shelters a lagoon of seagrass, mangrove and coral.

The Grand Cul-de-Sac Marin is a wide, shallow bay between the two wings of Guadeloupe. Across its mouth runs a barrier reef that is often described as one of the longest in the Lesser Antilles. Inside, protected from the open-ocean swell, is a lagoon dotted with small islets and sand cays, carpeted with seagrass and fringed by some of the most extensive mangrove forests in the eastern Caribbean.

This combination of reef, seagrass and mangrove works as a single system. Mangroves and seagrass meadows act as nurseries for juvenile fish, lobster and conch and trap sediment washing off the land; the barrier reef breaks the waves that would otherwise erode the shore. Many fish that live on Guadeloupe’s outer reefs spend their early life in the lagoon. The area forms the core of the marine part of the Guadeloupe National Park and is recognised internationally as a wetland of importance and part of a UNESCO biosphere reserve. Visitors usually explore it by boat, with snorkelling on the reef and around islets such as Îlet Caret.

The Cousteau Reserve and the Pigeon Islets

Guadeloupe’s best-known dive and snorkel site sits off the leeward coast of Basse-Terre.

The Pigeon Islets (Îlets Pigeon) lie a short boat ride off Malendure beach near Bouillante, on Basse-Terre’s sheltered Caribbean coast. The surrounding waters are protected within the national park and are popularly known as the Cousteau Reserve, after Jacques Cousteau, who is said to have praised the site. Calm water, good visibility and steep slopes covered in sponges, sea fans and hard corals make it the centre of diving in Guadeloupe.

Because the islets sit on the flank of a volcanic island, the bottom drops away quickly, so snorkellers can enjoy shallow reef close to the rocks while divers follow the slopes deeper. Fish life is rich thanks to protection from fishing, with schools of reef fish, turtles that are frequently seen around Malendure, and an underwater bust of Cousteau that has become a well-known landmark for divers.

A butterfly of two geologies

Volcanic Basse-Terre and limestone Grande-Terre support very different reefs.

Basse-Terre, the western wing, is high and volcanic, rising to the active La Soufrière volcano and covered in rainforest. Its coasts drop steeply into deep water, rivers deliver sediment after heavy rain, and coral grows as narrow fringes and patches on hard volcanic rock, best in sheltered spots like the Pigeon Islets. Grande-Terre, the eastern wing, is low and built of limestone. Its shores shelve more gently and offer wider shallow shelf, so reefs there are broader, with fringing reefs off beaches such as those near Sainte-Anne and Saint-François.

The outer islands add more variety. Les Saintes, a small volcanic group to the south, has a sheltered bay and rocky reefs. Marie-Galante, a round limestone island, has fringing reefs and seagrass on its shallow coasts. La Désirade, off the eastern tip, is exposed to the Atlantic and has a protected nature reserve. For the volcanic islands to the south, compare our Dominica coral reef maps and Martinique coral reef maps.

Reef life in Guadeloupe

Typical eastern Caribbean reef life, boosted by lagoon nurseries and protected areas.

Guadeloupe’s reefs hold the corals and animals typical of the eastern Caribbean: brain, star and finger corals, sea fans and sea whips, and large sponges on the deeper slopes. Parrotfish, surgeonfish, angelfish, butterflyfish, grunts and snappers are common, with moray eels, spiny lobster and octopus in the reef framework. Hawksbill and green turtles feed on reefs and seagrass, and the lagoon of the Grand Cul-de-Sac Marin shelters juvenile fish among mangrove roots. To learn more about how these species connect, see the coral reef ecosystem food web.

Guadeloupe is also part of the Agoa marine mammal sanctuary that covers the waters of the French Antilles, and whales and dolphins are seen offshore, particularly along the leeward coast of Basse-Terre.

Reefs, fisheries and protection

French and European frameworks support reef protection, but local livelihoods still depend on the sea.

Reefs, seagrass and mangroves support small-scale fisheries for reef fish, lobster and conch, and they underpin tourism built on diving, snorkelling, boat trips and beaches. The barrier reef of the Grand Cul-de-Sac Marin and the fringing reefs of Grande-Terre also protect low-lying coasts and harbours from waves and storm surge.

As a French overseas department, Guadeloupe’s reefs come under French environmental law. The Guadeloupe National Park manages core marine areas including the Grand Cul-de-Sac Marin and the Pigeon Islets, and French research institutions and reef-monitoring networks track reef condition over time. Find out more about why this matters on our coral reef conservation page.

Threats to Guadeloupe’s reefs

Heat stress, disease, runoff, Sargassum, storms and fishing pressure.

Like reefs across the Caribbean, Guadeloupe’s coral has suffered from marine heatwaves and bleaching and from coral diseases, including stony coral tissue loss disease, which has spread through the region. Land-based pollution is a particular issue: sediment and nutrients from farmland and towns reach the coast, and the long-lasting pesticide chlordecone, once used on banana plantations, contaminates soils and some coastal waters. Massive Sargassum seaweed strandings have hit many shores in recent years, and hurricanes such as Maria in 2017 have damaged reefs and coasts. Overfishing of reef fish and coastal development add further pressure.

Protection through the national park, better water quality and continued monitoring give Guadeloupe’s reefs the best chance of coping with a warming sea. For the regional story, read causes of coral reef destruction in the Caribbean.

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