BEAUFORT -- The number of loggerhead turtle nests in Beaufort County and throughout the state declined by more than 30 percent from 2006 to 2007, but experts say nesting numbers are cyclical, and this year's declines indicate reproductive patterns more than population concerns.
However, the number of loggerhead turtle nests discovered in South Carolina has dropped about 3 percent annually since 1980, causing concern for some scientists following the species, which the federal government classifies as "threatened" under the Endangered Species Act.
Loggerhead nests on 24 South Carolina beaches are monitored daily by volunteer crews that scour the beach for turtle tracks each morning during the egg-laying season, which extends roughly from mid-May through mid-September, said Bonnie Wright, president of nonprofit Friends of Hunting Island. The nests typically contain between 60 and 160 eggs, with an average of about 100, she said.
The crew found 64 nests on Hunting Island this year, two more than last year, making Hunting Island the only spot in Beaufort County where an increase was found. Otherwise, the number of nests in the county dropped from 336 to 192, even though one additional beach, on St. Phillips Island, was included in the search this year.
Wright pointed out that the Hunting Island State Park beach nourishment project provided more dry sand for the turtles to nest in, and the park strictly enforces a policy of turning off all lights at night, which should prevent turtles from being frightened away from the beach. In fact, the island's nourishment project was scheduled so it wouldn't conflict with the nesting season.
But while those factors may make the beach a more hospitable place for expectant mothers, it won't attract them to a particular beach.
"Turtles don't go back to the exact same beach (where they laid eggs before). They are working a region," said DuBose Griffin, state sea turtle coordinator for the South Carolina Department of Natural Resources. "Looking at it beach-by-beach really doesn't tell much."
She added that it is difficult to compare a large beach such as Hunting Island with smaller beaches in the Beaufort County study, such as on Fripp Island. Fripp Island had 14 nests this year and 31 in 2006.
Hilton Head had most nests
Hilton Head Island had the greatest number of nests in Beaufort County this year, with 112, down from 186 in 2006. Daufuskie Island had 15, down from about 25.
On Pritchards Island, 26 nests were found, down from 66, and 18 were found on Harbor Island, down from 28. Seven nests were found on St. Phillips Island in 2007, the first year that beach was included in the study.
Overall 1,686 nests were found on the 24 beaches in the South Carolina study this year, down from 2,568 nests on 21 beaches last year. An aerial survey found 2,558 nests this year, compared with 3,679 last year.
The greatest number of nests found in a single year since 1980 was in 1981, when 6,687 nests were discovered in the aerial survey.
The downward nesting trend in South Carolina likely isn't a result of actions by South Carolinians, specifically, Griffin said.
"What ends up on the beach is a result of what's happening in the water, their ability to survive," she said. "And 90 percent of the time, they are not in this area."
Female sea turtles typically lay eggs once every two to five years after they reach maturity between age 20 and 30, Griffin said. In the interim they migrate to feeding areas as far away as New Jersey.
Loggerheads' ability to feed may have been affected in recent decades by increased human consumption of marine organisms such as scallops and crabs, which could contribute to the declining loggerhead population, according to a federal report released in August. Global warming is also a threat to the turtles, the report states, noting that changes in water temperature affect availability of loggerhead prey.
The most significant human factor affecting the loggerhead population, however, is unintentional capture of loggerheads in fishing nets, according to the report, which said tens of thousands of loggerhead deaths occur each year in the Atlantic Ocean and the Gulf of Mexico due to such accidents.
Loggerhead nestings have dropped about 7 percent annually in the Gulf of Mexico, 4 percent in Florida and 2 percent in Georgia during recent years, according to the report.
Griffin said, however, that scientists are still uncertain what is causing the decline in loggerhead nestings.