Horseshoe crabs hold beach party

June 13, 1995|By Andrea F. Siegel | Andrea F. Siegel,Sun Staff Writer

The thermometer read 60 degrees, but things were smoldering on Beverly-Triton Beach -- at least for the horseshoe crabs.

In their world, this bit of the Mayo Peninsula in Anne Arundel County was the hottest spot in the Chesapeake Bay. And with a full moon and high tide, yesterday's predawn hours should have seen the annual peak for horseshoe procreation.

But only 73 of the prehistoric creatures were found at the water's edge at 5:30 a.m. Biologists from the Maryland Department of Natural Resources counted 597 horse shoe crabs last year.

"Maybe today wasn't the peak," said DNR biologist Thomas J. O'Connell, coordinator of Maryland's survey of horseshoe crabs. Maryland officials decided to survey the crabs because recent checks show dips in the Delaware Bay's horseshoe crab population.

Moonlight and waves crashing along the sand make great movie backdrops, like the scene in "From Here to Eternity" with Burt Lancaster and Deborah Kerr, but those thunderous waves can slam a 7-pound horseshoe crab onto the rocks or leave it upside-down on the beach, making it especially vulnerable to raccoons.

Biologists say the horseshoe crab's place in the food chain merits protection. Migratory shore birds replenish their fat by feasting on members of the ancient, 10-legged species. The adults are favored by the Atlantic loggerhead turtle, Mr. O'Connell said.

In recent years, the crabs have been used as bait for eels, catfish and conch. About 1 million pounds of horseshoe crabs were harvested in 1993, up from about 400,000 pounds in each of the previous 10 years, according to the National Marine Fisheries Service.

At sunrise yesterday, the biologists studying the arthropods along Beverly-Triton Beach were akin to Robert Cummings' professor studying the mating rituals of Frankie Avalon and Annette Funicello in "Beach Party." The biologists and the professor knew little about their subjects.

Biologist Beverly Sauls drilled holes in crabs and screwed in orange tags. The state wants to tag 10,000 to see if the crabs return to the same beach and whether the bay has its own population.

"The goal of the survey is to find spawning beaches," Mr. O'Connell said. The information may be used to rank beaches and help issue permits for riprap.

Five spawning sites turned up last year, the Ocean City area being the chief. But Beverly-Triton Beach, an Anne Arundel County park with a mix of sandy shoreline amid jetties and bulkheads, was the favorite place in the bay. About 50 beaches have been identified around the state.

The brownish-olive horseshoe crab has been around for 360 million years, long before the earth's land mass broke into continents. They preceded the dinosaurs and watched them disappear.

Whether because of gravitational pull or sensitivity to moonlight, the crabs have chosen to spawn around the full moon. Males cruise shallow water in search of a female. The larger female drags males onto the beach to fertilize the thousands of bead-like eggs she deposits in the sand.

Although 90,000 eggs over a few months sounds like a big brood, only two will survive to maturity, said Harley J. Speir, chief of the estuarine and marine fisheries program.

If the crabs make it past the predators and the humans looking for eel bait, they still have to worry about being "bled." Their blood is used to find toxins in prescription drugs. Those returned to the ocean after capture have a mortality rate 10 percent higher than normal.

Maryland is expected to join Virginia, New Jersey and Delaware this year in regulating the horseshoe crab harvest, said David P. Blazer, assistant to the director of tidewater fisheries in the DNR. Proposed regulations would limit how many crabs could be taken for personal use, restrict trawling and make reporting a catch mandatory.

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