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Long IslandNassau

Volunteers get education on horseshoe crabs

Volunteer Allie Holtzer of Wantagh introduces herself during

Volunteer Allie Holtzer of Wantagh introduces herself during a briefing for volunteers participating in the 2012 horseshoe crab tagging and spawning survey at Sagamore Hill. (May 2, 2012) Credit: Barry Sloan

Most visitors are drawn to Sagamore Hill to learn about Theodore Roosevelt, but one recent morning more than a dozen people gathered in a conference room for a briefing on the sex lives of horseshoe crabs.

Civilian volunteers joined National Park Service staff for training on how to count and tag horseshoe crabs as part of a population survey being conducted at national park beaches in the Northeast this spring.

The information gathered during May and June at Sagamore Hill in Cove Neck and other parks will be used by the parks to better manage the crab habitat. It will be forwarded to the state and federal Mid-Atlantic Fishery Management Council to better manage harvesting of the crabs used for bait, and to the U.S. Fish and Wildlife Service.

The volunteers who came to Sagamore Hill to be trained by Patti Rafferty, a park service coastal ecologist based at Fire Island, included students, retired teachers, biology buffs and James Foote of Sea Cliff, who usually turns up at Sagamore Hill to portray the 26th president.

"I was fascinated by horseshoe crabs since I was this high," Foote said, placing his hand near his knee.

Allie Holtzer of Wantagh volunteered because she had just graduated from college with a degree in history and was looking for something to do before entering the Peace Corps. "I love the water and marine life and I love that I grew up on an island so it's great to learn about the creatures around it," she said.

Mary Wagner, 71, of Wantagh came with her husband, Wayne, a volunteer docent who usually gives tours of Roosevelt's mansion, now closed for restoration. "I have a tremendous interest in horseshoe crabs," she said. "I think they're interesting and I feel sorry for them because they are harvested by fishermen."

The volunteers listened attentively to Rafferty, whose interest in the species was telegraphed by the American horseshoe crab pin on her shirt and matching earrings.

"The purpose of the project is to better understand how the horseshoe crabs are using the national parks in the New York area as habitat," she explained. "We believe that we may be providing areas of refuge that haven't been developed" and are not subject to harvesting while development has reduced the areas where the horseshoe crabs can survive.

She said surveying began at Cape Cod National Seashore a decade ago because of issues raised by harvesting by fishermen. The work expanded to three beaches at Fire Island last year and Sagamore Hill and Gateway National Recreation Area in New York City this year.

Researchers don't know if the crabs come back to the same beaches year after year. They do know they move around quickly and can travel very far. A horseshoe crab tagged at Sagamore Hill last year showed up five weeks later in Connecticut.

Counting the crabs that come ashore to mate and lay eggs and affixing a tag to some of them to be able to follow their travels will help fill in some of the blanks, Rafferty said.

She began the training with Horseshoe Crab 101. "They are an important part of the ecosystem," she said. "Their eggs are an important food source for many species, especially shorebirds." And they are used for bait by fishermen and their blood for medical testing.

Males and females mate and the female crabs come ashore at unusually high tides to dig a nest in the sand to lay their eggs. "They time their spawning to the highest tides of May and June, and those highest tides occur during the full and new moons," Rafferty said. "So we go out and survey two days before, the day of the full and new moon, and two days after."

Only a handful of horseshoe crabs showed up on the first cycle of the survey in early May but the researchers are hoping for better results in the next round starting Friday.

Rafferty noted that horseshoe crabs are one of the world's oldest animals -- more than 300 million years. "As old as they are," she said, "we don't know a lot about horseshoe crabs."


Horseshoe Crab facts












  • Despite its common name, the horseshoe crab (Limulus polyphemus) is more closely related to spiders and scorpions than crabs.
















  • Horseshoe crabs come to shore to mate and lay eggs with peak spawning in New York in May and June, particularly during the evening high tides of new and full moons.
















  • A female will lay 90,000 eggs or more during a spawning cycle; only about 10 will make it to adulthood.
















  • Many spring migratory shorebirds and fish rely upon the eggs for food.
















  • Native Americans and colonists used horseshoe crabs to fertilize crops.
















  • Horseshoe crabs have blue blood because the protein that carries oxygen in horseshoe crab blood contains copper. The blood is used by the biomedical industry for testing and sells for up to $5,000 per quart.
















  • The crabs are harvested for conch and eel bait.








    Source: National Park Service


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