Living Coral Reef Rediscovered Off Benin Coast

Scientists have discovered a living mesophotic coral reef off the coast of Benin, in the Gulf of Guinea, overturning a long-held assumption that the ecosystem had died out in the 1960s. During an expedition in September 2026, a research team used sonar technology and underwater cameras to survey this largely unmapped stretch of West African ocean. Their work revealed healthy coral communities at depths of more than 50 meters, surrounded by various species of reef fish. This find offers new insight into the regional marine environment and suggests that other underwater habitats may be waiting to be identified or re-evaluated.

The reef was first documented during surveys in 1963 and 1964, though those studies were primarily interested in finding fishing grounds rather than mapping coral health. At the time, researchers noted coral at depths between 52 and 56 meters but concluded the structures were no longer living. Following decades without further study, a team returned in 2025 under the Coral Reefs Rediscovery and Exploration project. They began by mapping the seafloor with side-scan sonar, searching for promising sites to deploy their imaging equipment.

This recent exploration covered approximately 7 kilometers of the seabed, identifying two locations with significant hard structures. Using an underwater drone and a stationary Deep Sea Camera, the team confirmed the presence of living coral at a depth of 54 meters. They observed at least six types of soft coral and two types of black coral, along with eight species of fish that use the reef for food and shelter. These mesophotic ecosystems thrive in deep water where sunlight is scarce, and they remain far less understood than their counterparts in shallower seas.

Gérard Zinzindohoué, the lead researcher from Benin's Institut de Recherches Halieutiques et Océanologiques, described the expedition as a demanding process involving long hours at sea and various technical hurdles. He spoke of the moment the cameras finally revealed the seafloor, noting a sense of disbelief after years of uncertainty regarding the reef. The team’s findings, published in Frontiers in Marine Science, represent the first confirmed visual evidence of living mesophotic coral along the Benin continental shelf and the first documented case in the Gulf of Guinea.

Even with this progress, much about the ecosystem remains unknown. While historical records suggest the reef system could span 40 kilometers along the coast, the team has surveyed only a small portion of that area. Additionally, because no physical samples have been collected, the identification of species relies entirely on camera footage. Zinzindohoué noted that the discovery points to how much is still hidden in West Africa’s coastal waters, suggesting a need for further exploration. While the survival of the entire reef system is not yet confirmed, the find highlights the marine biodiversity that exists beneath the surface.