Loggerhead Turtle Deaths a Mystery
Washington Post Staff Writer
Saturday, June 27, 1998; Page B1
For the threatened loggerhead turtle, the migrating season is over and the dying season has begun.
Dead turtles are washing up in record numbers along the Virginia coast and in the Chesapeake Bay. And no one knows why.
"The signs point to it not being a natural death," said Mark Swingle, a marine biologist and curator of the Virginia Marine Science Museum's stranding center in Virginia Beach. The center has found 122 dead loggerheads so far this season, and an additional 28 or so have been found by the U.S. Fish and Wildlife Service and the Virginia Institute of Marine Science in Gloucester Point.
"It does break your heart, especially when you see so many," said Joyce Moore, 63, a volunteer on the turtle stranding team who has helped photograph and identify more than 40 dead turtles so far this season.
Some turtles also have washed up on North Carolina beaches, but the deaths "are running about average right now," said Jean Beasley, director of the Topsail Turtle Project.
Scientists estimate that 5,000 to 10,000 loggerheads migrate up the coast each summer from as far away as South America, coming to the Chesapeake to feed and grow. Typically many weaker turtles die during the migration, victims of bad health or bad luck.
"The weak ones are more susceptible to things that might be in their way, like fishing nets or boats or whatever," Swingle said.
Still, the numbers are higher this year. In all of 1997, the crew at the Virginia Marine Science Museum, which consists of three staff members and 120 volunteers, responded to 115 strandings.
Necropsies performed on some dead turtles have revealed stomachs full of food mainly the horseshoe crabs that loggerheads prefer indicating that disease is probably not the cause.
"Normally, an animal that's feeding and otherwise healthy doesn't just keel over and die," Swingle said. "If a turtle is diseased, it's thin and clearly not nutritionally well off, and we're not seeing that. These turtles aren't thin."
In addition, there have been no telltale traces of collisions with boats, such as propeller marks or cracked shells.
"These turtles look fine," Swingle said. "They don't have any external signs of trauma."
The loggerhead was placed on the endangered species list as a threatened species in 1978. The turtles lay their eggs in the sand, mostly south of Virginia, but their numbers have been hurt by the loss of nesting beaches to development and the use of night-time beach lighting, which can disorient turtles trying to get ashore. Fishing nets used by trawlers and gill-netters are also a threat.
"There is the possibility that these turtles are being caught in fishing nets, but we don't have evidence of that," Swingle said. "We don't like to do too much speculating without evidence because that's not really fair to the commercial fishermen."
This year's big die-off will almost certainly prompt more turtle observers both unpaid volunteers and paid people on the staffs of wildlife organizations to be on the lookout for the well-being of the turtles this time next year. Moore said she will be one of them.
"It seems like an inordinate amount of turtles have died for this early in the year," she said. "I'm hoping we're going to find out why."
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