CURRENTS: SCIENCE & CONSERVATION

The report is as chilling as ice: 85 percent of the world’s oyster beds present 100 years ago are gone, and the rest are in severe decline. Even in the shell-rich Lowcountry, about half the beds are gone.

The hope for saving these oysters lies with leading-edge restoration efforts like those under way in South Carolina, according to a first-of-its-kind global assessment of oyster reefs. The Nature Conservancy report calls oyster reefs “one of, and likely the most, imperiled marine habitat on earth.”

The report this summer followed a National Oceanic and Atmospheric Administration study last year that indicated nearly half the coral reef ecosystems in United States territory are in poor or fair condition, and the Caribbean Sea had lost half its coral systems in less than five years.

“I think oysters are going to start getting the attention that coral reefs did,” said Joy Brown, a Nature Conservancy marine restoration specialist in Charleston.

That’s the value of the odd-looking, castle-like stacks of shell and concrete blocks the conservancy has placed along Jeremy Island on the Intracoastal Waterway near McClellanville. They are “oyster castles,” a sort of substitute shell bed to which oyster spat, or larvae, can attach and begin their own oyster reefs. Unlike recycled shell beds, the three-dimensional castles create a nooks-and-crannies habitat for oysters, crabs and other species.

The reefs also help control marsh erosion.

The Jeremy Island site is a pilot project that could be extended throughout the Lowcountry as well as elsewhere, rebuilding entire oyster reef ecosystems, if it works and grant money can be lured.

The castles aren’t hard to come by; recycled shells have been. Some 80,000-90,000 bushels of oysters are harvested in South Carolina each year. Despite running a reef restoration program since the early 1990s, the S.C. Natural Resources Department still has to buy some 60 percent of more than 30,000 bushels of shells that are placed in the water to build new beds annually.

And budget cuts crimped the program this year; only 28,000 bushels were planted.

This month, the conservancy and the Natural Resources Department will launch a restaurant shell recycling project with an $18,000 grant from the U.S. Fish and Wildlife Service, which potentially could bring in that other 60 percent of shells, Brown said. Restaurants use the majority of the oysters harvested, and she hopes at least 19 Charleston area restaurants will take part.

“It’s something outside the box,” she said, “something a lot of people haven’t done before.”

The report, “Shellfish Reefs At Risk,” blames the loss of oyster reefs on destructive fishing practices, coastal development and water pollution.

“We’re seeing an unprecedented and alarming decline in the condition of oyster reefs, a critically important habitat in the world’s bays and estuaries,” said Mike Beck, the report’s conservancy marine scientist and lead author. “However, realistic and cost-effective solutions within conservation and coastal restoration programs, along with policy and reef-management improvements, provide hope for the survival of shellfish,” he said in the news release.

In South Carolina, Beaufort County received one of the report’s few “good” ratings — meaning fewer than half of its oyster beds have been lost in the past 100 years. Charleston County received a “fair” rating, indicating a loss from 50 percent to 90 percent.

Oyster habitat in South Carolina has gradually declined over the past two decades. The S.C. Department of Health and Environmental Control has closed about one-third of the state’s 3,000 acres of oyster beds to harvesting because of pollution. But the annual harvest has remained about the same, and Natural Resources officials disagreed with the report findings.

“We don’t think we’re nearly so bad. Our stocks have been fairly stable the past couple of decades,” said David Whitaker, Natural Resources fisheries management director. “The numbers of our oysters are actually pretty good.”