High Biodiversity of Mozambique Channel Coral Reefs Need Protection, Study Says

The coral reefs of the Mozambique Channel are a hotspot for biodiversity and the leading candidate for a prioritized conservation effort, according to a new study.

Writing in the journal PLOS One, an international team of researchers report their efforts to gauge which of the world's coral reef ecosystems have survived the effects of rising ocean temperatures and human-induced damage to the marine environments.

Working in 11 countries over seven years, the research team, which included experts from the Wildlife Conservation Society, the University of Warwick, the ARC Centre for Excellence of Coral Reef Studies, Simon Fraser University, University of North Carolina at Chapel Hill, and other groups, studied nearly 300 coral reef sites around the world.

The research team concluded that the coral reef systems in the Mozambique Channel should "be a priority for protection" and climate change continues to affect the seas.

"Determining which reef systems possess a measure of resistance to climate change requires knowing how they have survived the many recent climatic disturbances" said lead study author Tim McClanahan, a senior conservation scientist at the Wildlife Conservation Society. "The Western Indian Ocean provides us with a variety of responses to disturbances that we can examine and distinguish environmental variation, resilience, adaptation, and other factors for a more informed view of management priorities and solutions to the climate crisis."

McClanahan and his collaborators analyzed coral reef sites from many locations along the African coastline, as well as island groups such as the Maldives, the Seychelles and others.

Their methods included randomly dropping a 10-meter line into a the water and identifying the coral along the line down to the genus. Another survey method included identifying every coral within a randomly selected 2-square-meter polygon.

Among all the sites included in the survey - 291 in all - reefs in the Mozambique Channel have the highest species diversity, promoted by the area's confluence of tides, currents, eddies, along with less exposure to waves and storms, the researchers said.

During the seven-year project, other sites with high coral diversity disappeared, the researchers said, adding that marine protected areas and no-fishing zones tended to have a higher percentage of coral cover. However, after a devastating event, such as a bleaching triggered by warming, these protections have no measurable effect on recovery.

"The remaining coral diversity of the Mozambique Channel presents us with an opportunity to safeguard these remaining ecosystems for posterity," said Caleb McClennen, Director of the Wildlife Conservation Society Marine Program.