Survey: Coral Reefs in Rough Shape
August 26, 2002
Scientists and divers monitoring the health of 1,107 coral reefs reported Monday that 95 percent have been affected by overfishing. In a report summarizing five years of surveys, the global network said at least four species of reef fish — hunted as food or to adorn aquariums — face extinction. It further asked nations to ban fishing of those four species.
“WHAT WE have seen is coral reefs have been damaged more in the last 20 years than they have in the last 1,000,” said Gregor Hodgson, a founder of Reef Check, a program at the University of California, Los Angeles. “Suddenly, the pressures of overfishing and damaging types of fishing – dynamiting fish and poisoning fish, particularly in Southeast Asia – have taken off.”
The four fish species identified as critically endangered were in two areas:
Caribbean: Nassau grouper were absent from 82 percent of shallow reefs — only eight reefs had more than one fish.
Southeast Asia: .Barramundi cod, bumphead parrotfish and humphead wrasse were missing from 95 percent, 89 percent and 88 percent of reefs, respectively.
“We would like to ask governments to immediately ban fishing and trade in these species,” Hodgson said in a statement accompanying the report. “If we do not, they will disappear completely.”
Dynamiting reefs is an especially destructive practice because it not only stuns reef fish for easy capture but also destroys the coral. Another technique in use is to poison fish with small amounts of cyanide, stunning them so that they can be captured.
More than 5,000 scientists and volunteers in about 60 countries have contributed to annual Reef Check surveys over the last five years.
The network noted that coral reefs, found in about 100 countries, are significant because their habitat provides food for 350 million people as well as genetic material for the pharmaceutical industry.
On top of that, Reef Check said, reefs protect the coast from wave erosion and provide the coral that nature uses to build coastal beaches.
ALGAE, POLLUTION CITED
Hodgson said plummeting populations of overfished species, including fish and sea urchins, can allow the algae they normally keep in check to smother coral and kill entire reefs.
In the case of sea urchins, the survey found a sharp drop in the abundance of the Southeast Asia black Diadema species from 1998 to 2000.
Pollution and increased amounts of sediments are also taking their toll. A recent study identified bacteria found in the intestines of humans and other animals as the cause of a white pox outbreak killing elkhorn corals in the Caribbean.
Many scientists also fear that global warming is worsening coral “bleaching,” a phenomenon in which coral turns white from stress caused by even small temperature changes. If prolonged, that stress can kill the coral.
Reefs where fishing has been banned or restricted show signs of recovery, the survey said. But virtually all the world’s reefs show signs of declining health.
Hodgson said that of 1,107 reefs surveyed, just one, near Madagascar, could be considered pristine.
VOLUNTEERS WERE KEY
Scientists organized the first international conference to discuss the global decline in coral reef health in 1993. Since then, they have struggled with how to devise a program to monitor the world’s reefs. Reefs make up just .09 percent of the area of the world’s oceans and are spread around the globe, making them difficult to study without the help of volunteers.
“The volunteer component is fantastic. How else can you reach so much of the coral reefs?” said Jamie Hawkins, deputy director of the National Oceanic and Atmospheric Administration’s National Ocean Service. NOAA, which helped pay for the report, intends to issue a national state-of-the-reefs report next month.
One contributor acknowledged the size of the survey precludes it from being as scientifically rigorous as a smaller study.
“There’s always a trade-off between quantity and precision. They got a lot of quantity and not a lot of precision,” said Jeremy Jackson, a professor at the Scripps Institution of Oceanography, who wrote the preface to the report.
But the report’s authors said the project is as much about science as it is about raising the public’s awareness of the coral reef situation. Information from Reef Check’s report is online at www.reefcheck.org