Caribbean Coral Reefs May Disappear in 20 Years: Can Decline be Reversed by Saving Parrotfish?

Caribbean coral reefs are facing steep decline. In fact, only about one-sixth of the original coral cover is left in these warm seas. Now, scientists have found that these reefs may completely disappear in the next 20 years.

The Caribbean reefs are important to island nations. They span a total of 38 countries, and are vital to the region's economy, generating more than $3 billion annually from tourism and fisheries and over a hundred times more in goods and services.

Caribbean reefs are facing a host of issues, including overfishing, climate change and coral diseases. In the past, climate change in particular was thought to be the main culprit of coral degradation. Yet it seems as if the loss of grazers is actually more of an issue. In a new report, researchers found that not only are reefs in steep decline, but what factors are leading to this decline.

"The rate at which the Caribbean corals have been declining is truly alarming," said Carl Gustaf Lundin, Director of IUCN's Global Marine and Polar Program, in a news release. "But this study brings some very encouraging news: the fate of Caribbean corals is not beyond our control and there are some very concrete steps that we can take to help them recover."

Parrotfish and sea urchin play important roles on the Caribbean reef. They eat algae, which can quickly overgrow reefs if not "trimmed" back by grazers. Unfortunately, a disease that swept through the Caribbean in 1983 caused the mass mortality of the sea urchin. In addition, extreme fishing has brought the parrotfish population to the brink of extinction in some regions.

"Even if we could somehow make climate change disappear tomorrow, these reefs would continue their decline," said Jeremy Jackson, the lead author of the new study. "We must immediately address the grazing problem for the reefs to stand any chance of surviving future climate shifts."

Yet it's possible to eventually reverse this decline. By being more responsible with fishing practices and encouraging the repopulation of parrotfish and sea urchin, it's possible to help reefs recover.

"This report confirms that vigorous populations of grazing parrotfish are a common attribute of the healthiest Caribbean coral reefs," said Terry Hughes, author of a 1994 study that predicted current problems due to parrotfish removal. "These 'resilient reefs' have strong local protections that are strictly enforced and double or triple the average coral cover of the 14 percent seen throughout the Caribbean."

The full report can be found online here.