Monitoring the Night of the Horseshoe Crabs

There were more than 50 of us gathered in the Moriches Bay side parking lot of Pike’s Beach on Dune Road in Westhampton Beach last night. It was almost dusk and more people just kept arriving. By 8 p.m., our leaders gave up counting us and took us down a long path, through the spartina at the water’s edge, to a thin strip of high-tide beach. There would be plenty of counting to do tonight without counting people.
Every year, at high tide around the full moon in June, ancient horseshoe crabs crawl out of the depths to lay their eggs in the sand near the water’s edge. This has historically been one of their prime egg-laying spots, but when we got to the beach and scanned the water, there wasn’t a horseshoe crab to be seen.
But our guides, Gina Mulhearn and Mark Cappiello from Cornell Cooperative Extension and South Fork Natural History Museum educator Lindsey Rohrbach, didn’t seem concerned. We were going to see one of nature’s greatest shows. It’s just that the feature presentation hadn’t started yet.
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The CCE scientists help run the New York Horseshoe Crab Monitoring Network, which collects data on the number, size and gender of horseshoe crabs that come up on the beach at 16 sites throughout Long Island early each summer.
They rely on citizen volunteers of all ages to help them tag and measure the horseshoe crabs.
Our group Wednesday night was full of very professional young scientists. Most of them had been alive for less than a decade, but many of them knew that horseshoe crabs are ancient. They knew they have blue blood that has all kinds of special medicinal powers. And they knew that horseshoe crabs are facing a lot of threats on the Eastern Seaboard.
Horseshoe crabs are some of the best bait around for conch fishermen, who historically have taken to the bays on these mysterious, full-moon June nights, to fill their pickup trucks with bait for the season.
New York has voluntarily reduced its quota for harvestable horseshoe crabs well below the level set by the Atlantic States Marine Fisheries Commission, and catching horseshoe crabs is prohibited at several sites on Long Island, including Cedar Beach in Mount Sinai and the Fire Island National Seashore, where they crawl ashore in massive numbers.
The setting sun of a cloud-filled sky was just about finished washing Moriches Bay with a pink glow as our guides began checking the air temperature (cold, windy) and the bay temperature (warm, bathtub), and then handed over Dremel tools and tags, great big horseshoe crab measuring calipers and clipboards to our young scientists, who seemed to already know exactly what to do with these scientific tools.
As if on cue, the horseshoe crabs began crawling in with the tide. The beach was getting tinier and tinier, but most of the kids were wearing water shoes or waders or big, rubber-bottomed L.L. Bean boots. They carefully measured, recorded, drilled and tagged, and then turned the horseshoe crabs around and sent them back out into the bay, while their parents looked out at the horizon, the ancient landscape, and then back in to the shore, now teeming with a mass of prehistoric life.
It was like being in a movie. But it was real.