April 3, 2006 – With coral reefs in decline because of disease and last fall's bleaching problem, residents can help eliminate man-made situations that negatively affect corals.
"We can do something about anchoring," said Jeff Miller, V.I. National Park biologist, launching into a list of problems on Monday.
Miller also cited sedimentation, over-fishing and nutrification as issues people can attack. He said that nutrification happens when leaking septic tanks and sewage systems flow into the ocean, and that fertilizers used on hotel landscaping contribute to this problem.
"These are all things that are manageable and bad for the reefs," he said.
Both Miller and Caroline Rogers, a marine ecologist at the U.S. Geological Survey on St. John, said that while coral disease has been around for some time, 2005 saw an unprecedented territory-wide bleaching event caused by extraordinarily warm water.
Just when the corals began to recover, they were hit by disease.
"We are seeing corals several hundreds of years old dying in a matter of a few weeks," Rogers said.
She said this event hit a wide variety of corals growing as much as 90 feet deep. Even shallow water corals like elkhorn suffered.
"Nobody's seen elkhorn bleach before in the Virgin Islands," she said.
Miller said that both near shore and offshore coral reefs were affected.
Zandy Hillis-Starr, chief of resources management at Buck Island Reef National Monument on St. Croix, said that island's reefs are in even worse shape than St. John's.
"It's not pretty out there," she said.
She said that St. Croix had warmer water for a longer period of time than St. John did.
Both Miller and Rogers said the bleaching was particularly alarming because the deeper corals provide the reef backbone.
Massive corals make up 90 percent of the reefs, Miller said. "And they grow only a millimeter a year," he said, while shallow water elkhorn coral grows extremely fast – several inches per year.
While the bleaching problem hit many areas of the Caribbean, Rogers said water temperatures were particularly warm in Puerto Rico and the Virgin Islands.
"We had more mortality than the rest of the Caribbean," she said.
Miller said a study showed that Caribbean coral reefs are important to the economy. He said the 2004 study by the World Resources Institute showed that the reefs are responsible for $3.1 billion to $4.6 billion worth of fishing, dive tourism and shoreline protection in the Caribbean.
Rogers said it's not known if the bleached corals will produce the larvae that enable them to reproduce.
Both said it's too early to know what this summer will bring in the way of water temperatures, but they worry about what's ahead for the territory's reefs.
Rogers said USGS and park staff are able to keep such close tabs on the coral because, as scientists, they regularly evaluate areas around the islands.
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