Arthropod Amour in Westhampton

As twilight’s warm colors drifted in long languid lines across the Shinnecock Inlet, small clusters of darkly armored crabs became faintly illuminated as they gathered in the breaking surf at high tide.

May Day’s new moon ushered in the horseshoe crab’s spawning season along the Atlantic Coast, and the confluence of a moonless sky, spring’s high tides and more than 100 amorous arthropods allowed for a strong kickoff to the annual Horseshoe Crab Spawning Survey on Long Island.

Since 2006, Cornell University Cooperative Extension of Suffolk County and the NYS Department of Environmental Conservation have recruited volunteers to participate in the survey from May to July. For the survey’s seasonal opening no volunteers turned up, but the count continued thanks to the DEC's Crustacean Unit Leader Kim McKown and site coordinators Mark Cappiello and Gina Mulhearn, who were all pleasantly surprised by the 100 plus crabs counted on the first night out.

Husband and wife site-coordinators Cappiello and Mulhearn have been volunteering with Cornell’s horseshoe crab survey for five years, because they live in Westhampton Beach and wanted to become more involved in the community.

“It’s a really beautiful place,” said Mulhearn, who has worked in global electronics. “I found out about the survey through the Barrier Beach Preservation Association and thought it was a great way to give back.”

For the next two months, volunteers will stroll 100 meters of sand, designated as a horseshoe crab spawning area on Pikes Beach, to count and tag the crabs. The data collected will be used to assess population trends, and document species’ characteristics and spawning patterns.

Every spring thousands of female horseshoe crabs make their way into the surf zone with one or two males in tow. After digging out a shallow hole near the water’s edge, they will deposit 20-100,000 eggs, which will later be fertilized by male crabs as they pass over the underwater egg nest— a process that has sustained these ancient creatures for more than 250 million years.

Despite the name, horseshoe crabs are not crustaceans. They are invertebrate animals called arthropods, more closely related to spiders and scorpions, with segmented bodies and external skeletons.

For many people, horseshoe crabs are just another creepy-crawly cockroach of the sea, so it might be difficult to understand why the species spawning habits need to be studied.

“Because this is a fished population, we need to keep count of males and females,” Mulhearn said. “The survey’s data is used to monitor the population and regulate the commercial fishing catch."

As a result of commercial overfishing and/or other environmental factors, the horseshoe crab population has dipped over the last decade, causing the DEC to limit New York’s commercial fishermen's take to 150,000 per year, much to their chagrin.

Both Cornell scientists and DEC environmentalists hope to use the study’s data to bolster efforts to protect this fascinating creature, whose eggs are a vital food source for migrating seabirds.  

“The survey is pretty young, so we haven’t noticed much of an increase in the population,” said McKown. “There was a significant dip in the late 1990s, and if we continue to get low numbers we may need to lower the commercial fishing take again."

In addition to being an important food source for the red knot and other seabirds, the horseshoe crab’s copper-based blood is used in medical laboratories to test the purity of medications and vaccines.

“If you get people to learn about the creatures that are here, they will care about them” said Mulhearn. "And if they care,  they will change their behaviors.”

Mulhearn went on to say that on full-moon or new-moon survey nights, families throughout East End are encouraged to participate.  An evening walking the beach, enjoying the beauty of the bay and learning something about the this amazing living fossil is an excellent way to volunteer your time.

To learn more about volunteering with the Cornell Horseshoe Crab Spawning Survey visit www.nyhorseshoecrab.org