Human Activities Threaten Coral Reefs, Part 1

BOB DOUGHTY:This is SCIENCE IN THE NEWS in VOA Special English. I'm Bob Doughty. FAITH LAPIDUS:And I'm Faith Lapidus. Today we tell about threats to coral reefs and some new discoveries about these ancient, biological structures. BOB DOUGHTY:Corals are groups of small organisms called polyps. Millions of polyps grow together to form coral reefs. America's National Oceanic and Atmospheric Administration, NOAA, says the coral reefs that exist today are up to fifty million years old. The ancestors of these reefs were formed at least two hundred forty million years ago. However, human activities are threatening the world's coral reefs. NOAA scientists say the main threats are pollution, overfishing and climate change. As a result, coral reef populations are decreasing worldwide. NOAA says an estimated twenty percent of the reefs have been damaged beyond recovery. About fifty percent of the remaining coral are under risk of collapse. FAITH LAPIDUS:Now there is a new threat facing coral reefs in the Caribbean Sea. The threat comes from another sea creature. A recent study found that damselfish are killing head corals in the Caribbean. Researchers say this is creating even more problems for the area's already troubled coral reefs. The journal PLoS ONE published a report about the study. Damselfish live in ocean waters throughout the world. They kill parts of coral colonies or communities, so that simple organisms like algae can grow. Damselfish use the resulting gardens of algae for feeding and producing young. BOB DOUGHTY:In earlier times, damselfish often used staghorn corals to grow in these areas. During this period, staghorns were the most common coral in the Caribbean. The coral's long, thin branches offered the damselfish great places to hide and feed. Even after damselfish killed off parts of the staghorn colonies, the areas that remained were able to survive. In recent years, coral diseases, storms and other activity in the environment have reduced staghorn coral populations. The corals are now listed as threatened under America's Endangered Species Act. FAITH LAPIDUS:Les Kaufman is a biologist with Boston University and Conservation International. He says the damselfish had to find new grounds for algae after the staghorn coral disappeared. He says the damselfish are now killing off parts of slow-growing coral. This coral is not able to recover from the destruction as well as its staghorn relative. Professor Kaufman says it could take the slow-growing coral as long as one hundred years to recover. BOB DOUGHTY:Earlier research suggested that overfishing was responsible for an increase in damselfish populations in the Caribbean. The research found that many of the bigger fish known to eat damselfish had disappeared from the area. Scientists said the increased damselfish populations led to the killing of more coral. The new study found that the number of damselfish is not the issue. Instead, researchers are blaming the increased killing of coral on the lack of staghorn coral in the Caribbean waters. FAITH LAPIDUS:A report in the journal Marine Policy draws attention to another threat to corals and other sea creatures. The report says international law has failed to protect coral reefs and the tropical fish that live among them from collectors. Researchers looked at information collected for the United Nation's conservation monitoring program. The researchers say the coral trade is removing about one million five hundred thousand live stony corals from the oceans each year. They say thirty million tropical fish are disappearing every year because of a growing interest in tropical fish. Many of the fish die while being transported. BOB DOUGHTY:Brian Tissot is a marine ecologist with Washington State University. He was one of eighteen researchers who wrote the Marine Policy paper. He says some kinds of reef fish are close to disappearing forever. The researchers say the United States represents more than fifty percent of the trade in coral and reef fish. They have urged America to take a position of international leadership in coral reef protection and to take steps to reduce the trade's environmental effects. Source: Voice of America