Report: Caribbean coral reefs down 80 percent
By Marsha Walton
(CNN) -- A new study paints a grim picture of the health of coral reefs across the Caribbean. In the past three decades, the amount of coral cover has dropped about 80 percent, according to researchers in the journal Science.
A team of U.K. scientists compiled data from 263 separate reef sites in the Caribbean for this week's report, which they called the most extensive coral study ever of the region.
Some of the causes are natural, such as disease and weather damage. Hurricanes, for example, can break coral tissue, making it more susceptible to diseases.
But much of the problem can be traced to humans.
"The man-made causes, the ones we can do something about, need to be taken extremely seriously," said study author Isabelle Cote, a biology professor at the University of East Anglia in Norwich, England.
"A lot of the important causes come from things people are doing on land, like pollution, sedimentation resulting from development and deforestation. They have very important repercussions," she said.
While the rate of coral loss is alarming now, it was even worse in the 1980s, researcher said.
The report said there is no convincing evidence yet that global warming is responsible for the reef declines during the years studied, 1975-2000.
The majority of data came from four areas of intensive research; Florida, Jamaica, the U.S. Virgin Islands, and the Mesoamerican Barrier Reef system in Central America. The most dramatic damage to those regions occurred in the 1980s.
About 11 percent of coral reefs have been destroyed and another 16 percent are considered severely damaged, according to the researchers.
Coral reefs, which exist in shallow, tropical waters all over the world, are complicated eco-systems that provide homes to fish, crabs, urchins, sponges and other creatures.
When something happens to one species in a reef, it can affect many others, Cote said. In the early 1980s, for example, coral diseases coincided with the disappearance of the black spiny sea urchin, which had kept algae on the reefs in check.
Designating reef areas as marine sanctuaries can help protect them, but scientists say enforcement remains a big problem with so many different countries involved.
Because coral communities grow slowly, the recovery rate for areas now under protection remains unclear. The reef could rebound with just the hardiest of species, scientists said, creating a new reef community that functions differently from the earlier one.
"There is a lot of goodwill out there. What there isn't enough of is money," Cote said. She said hotels and resorts in the region that depend on scuba diving, snorkeling and eco-tourism are "shooting themselves in the foot" if they don't protect the fragile waters around them.
Most of Cote's research over the past 20 years has been in Barbados, a region where the coral has degraded dramatically over the past decade.
"Just from an economic standpoint, it makes sense to protect these areas," she said.