Brazil: Coral Diseases Endanger Reefs

Provided by Ronaldo Francini-Filho and Fabiano Thompson of the Universidade Federal da Paraiba, and Rodrigo Moura of Conservation International, Brazil

White-plague Mussismilia braziliensis. Photo credit: Ronaldo Francini-Filho

The Abrolhos Bank, off the shores of the populous state of Bahia in northeastern Brazil, is home to the largest and richest coral reefs in the South Atlantic.¹ Eight of the 18 coral species commonly found in the Abrolhos Bank occur only in the South Atlantic, with one species (Mussismilia braziliensis) endemic to the eastern Brazilian coast alone. Brazil’s reefs are also a primary source of food and employment for thousands of people along the coast.²

In the last 20 years, the Bahia coast has experienced increased tourism, urbanization, and large-scale agriculture, leading to the discharge of untreated wastes, fertilizers, and nutrients that contaminate the region’s reefs. Destruction of the Atlantic rainforest has also led to increased erosion and a high influx of land-based sediments onto the reefs. As a result, pathogenic bacteria are now common on the reefs.³

Coral disease prevalence on the Brazilian coastline has escalated from negligible to alarmingly high levels in recent years. Scientists have recorded six types of diseases on the Abrolhos Bank.⁴ White-plague-like disease was by far the most common, affecting primarily the key endemic reef coral M. braziliensis.

Studies link the global proliferation of coral diseases to elevated seawater temperature and to the human impacts mentioned.⁵ Should disease-induced coral mortality continue, Brazil’s reefs will suffer a massive coral cover decline in the next 50 years, and M. braziliensis will be nearly extinct in less than a century. If seawater temperatures continue to rise and local threats continue to plague Brazil’s reefs, these ecosystems may collapse even sooner.

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