WASHINGTON, D.C.: A new study has found that the dramatic decline of Caribbean coral reefs can be reversed.
The study by the Global Coral Reef Monitoring Network (GCRMN), the International Union for Conservation of Nature (IUCN) and the United Nations Environment Program (UNEP), has also found that Caribbean corals have declined by more than 50 per cent since the 1970s.
But according to the authors, restoring parrotfish populations and improving other management strategies, such as protection from overfishing and excessive coastal pollution, could help the reefs recover and make them more resilient to future climate change impacts.
“The rate at which the Caribbean corals have been declining is truly alarming,” said Carl Gustaf Lundin, director of the Washington-based IUCN’s Global Marine and Polar Program. “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.”
With only about one-sixth of the original coral cover left, the study finds that most Caribbean coral reefs may disappear in the next 20 years, primarily due to the loss of grazers in the region.
According to the IUCN, the world’s oldest and largest global environmental organization, the study, Status and Trends of Caribbean Coral Reefs: 1970-2012, is the most detailed and comprehensive report of its kind published to date.
It said the study is the result of the work of 90 experts over the course of three years.
IUCN said the study contains the analysis of more than 35,000 surveys conducted at 90 Caribbean locations since 1970, including studies of corals, seaweeds, grazing sea urchins and fish.
The report shows that while climate change has long been thought to be the main culprit in coral degradation, it poses a serious threat by making oceans more acidic and causing coral bleaching.
The report finds that the loss of parrotfish and sea urchin – the area’s two main grazers – has, in fact, been the key driver of coral decline in the region.
It says that an unidentified disease led to a mass mortality of the sea urchin in 1983, adding that extreme fishing throughout the 20th century has brought the parrotfish population to the brink of extinction in some regions.
“The loss of these species breaks the delicate balance of coral ecosystems and allows algae, on which they feed, to smother the reefs,” the report said, noting that reefs protected from overfishing, as well as other threats, such as excessive coastal pollution, tourism and coastal development, are more resilient to pressures from climate change.
“Even if we could somehow make climate change disappear tomorrow, these reefs would continue their decline,” warned Jeremy Jackson, lead author of the report and IUCN’s senior advisor on coral reefs. “We must immediately address the grazing problem for the reefs to stand any chance of surviving future climate shifts.”
The study also shows that some of the healthiest Caribbean coral reefs are those that harbour vigorous populations of grazing parrotfish.
These include the Flower Garden Banks National Marine Sanctuary in the northern Gulf of Mexico, Bermuda and Bonaire, “all of which have restricted or banned fishing practices that harm parrotfish, such as fish traps and spearfishing”.
The study is urging other countries to follow suit.
“Barbuda is about to ban all catches of parrotfish and grazing sea urchins, and set aside one-third of its coastal waters as marine reserves,” said Ayana Johnson of the Waitt Institute’s Blue Halo Initiative, which is collaborating with Barbuda in the development of its new management plan. “This is the kind of aggressive management that needs to be replicated regionally if we are going to increase the resilience of Caribbean reefs.”
The IUCN said that reefs where parrotfish are not protected have suffered tragic declines, including Jamaica, the entire Florida Reef Tract from Miami to Key West, and the U.S. Virgin Islands.
The IUCN said the Caribbean is home to nine per cent of the world’s coral reefs, which are one of the most diverse ecosystems on the planet.
It said Caribbean reefs, spanning a total of 38 countries, are vital to the region’s economy, generating more than US$3 billion annually from tourism and fisheries, and over a hundred times more in other goods and services, on which more than 43 million people depend.