Saving The Horseshoe Crab

By C. Trottere

The email from the biologist said to meet on the night of the new moon, 10 p.m. at Cedar Beach in Mount Sinai. It sounded like the makings of a romantic tryst and it was in a sense, but not for humans. May through June is horseshoe crab spawning season, when thousands of these living fossils come ashore along the Eastern seaboard to spawn and make more little horseshoe crabs. They’ve been doing it for about 455 million years, before dinosaurs were here.

The horseshoe crab, or Limulus polyphemus, is clouded in many misconceptions. First of all, they’re not crabs. They are actually more closely related to spiders than to crustaceans. I’ve always loved horseshoe crabs and yet I don’t even like spiders a little bit. Go figure.

Many people also mistake the horseshoe crab’s sword-like tail (telson) for a stinger. It’s not. The telson is a survival tool, used as a lever, to help the horseshoe crab flip over when it gets tossed onto its back from waves along the shoreline. For all their intimidating looks, with their five pairs of legs and 10 eyes, these creatures are totally peace loving and harmless. They’re the Tibetan Monks of the sea.

So that’s why I decided to be part of a group of volunteers who would be learning how to tag horseshoe crabs for study purposes. It’s all part of a long-term biological study headed by Drs. Jennifer Mattei and Mark Beekey, professors from the Biology Department at Sacred Heart University (SHU) called “Project Limulus.”

The aim of the study, which is currently being funded by Connecticut Sea Grant, is to better understand the ecology of horseshoe crabs in the Long Island Sound, therefore, learning better how to effectively manage them. The Long Island Sound Study Outreach Coordinator of New York Sea Grant and the New York State Department of Environmental Conservation (NYSDEC) work together with the SHU staff in coordinating volunteers on our side of the Sound.

“In the early 1990’s, trawl data from state research vessels noted a marked decline in the number of horseshoe crabs caught from Delaware up through New York and Connecticut including Long Island Sound (LIS),” Dr. Mattei said. “While the species is not endangered and may still be harvested, their economic value and importance to the LIS ecosystem warrant a closer look at their own ecological needs to make sure we have plenty of horseshoe crabs for future generations.”

Here a tagged horseshoe crab heads back into the water.

When I arrived at the appointed location for the tagging session, I knew I was not the only person in love with limulus. If you think that spending a Sunday night around horseshoe crabs makes me a little odd, then tell that to the other 50 people who were also there that night, armed with flashlights, water shoes and curiosity. Several parents had brought their children along for the educational experience.

Lisa Volpe of Miller Place was there with her son Nicholas, 10, who was participating in the tagging as part of his school’s enrichment program. Nick, who is in fourth grade, thought getting to hold the horseshoe crabs was the best part, as he fearlessly juggled several at a time.

Doreen Buckley of Sound Beach, was there with her son, Jake,10.

“It’s awesome,” she said. “The kids are so excited and having fun.”

Eric Powers, a field biologist in attendance for the tagging night, said that the large crowd was inspiring.

“It gives me hope for the future to see that it’s fashionable to be green again,” he said.

Larissa Graham, New York Sea Grant’s Long Island Sound Study Outreach Coordinator, helped to instruct everyone on how to use the awl, a piercing tool that looks sort of like a door stop, to punch a hole in the horseshoe crab’s shell, and then push the plastic numbered tag into the hole. Then the tagger must fill out a form stating the tag number, the sex of the horseshoe crab (males have a front pincher that looks like a boxing glove), where it was tagged and what it was doing when you tagged it (Mating? Alone?).

Dr. Mattei explained that this tagging portion of the research is really the first part of the “Project Limulus, Mark/Recapture” study. Once the horseshoe crabs are tagged, people who spot them need to report the sighting.  (See “What to do if I see one.”)

“This study is important because it not only provides valuable data to help researchers learn about these creatures, but it also gets kids and adults outdoors and learning about the animals that live in Long Island Sound, just minutes away from their homes,” said Graham. ‘Hopefully, our volunteers will gain a new appreciation for Long Island Sound and its creatures and will help us protect this valuable resource.”

Dr. Mattei, who is obviously quite a multi-tasker, gave everyone a mini-biology lecture too, simultaneously talking and demonstrating the tagging process in her wading boots under the new moon.

Jen holding HSC, LI Press-Dr Jennifer H. Mattei of Sacred Heart University, holds a horse shoe crab and tells listeners about the wonders of the living fossil.

She described how horseshoe crabs have unique copper-based blue blood with very special properties. Back in the 1950’s scientists at the Marine Biological Lab in Woods Hole, Massachusetts discovered that the crab’s blood contained cells called amebocytes that could attack bacteria. Using a derivative of the blood (Limulus Amebocyte Lysate or LAL) from the crabs, scientists developed a test for bacterial contamination. All flu vaccines are tested for bacterial contamination using the LAL as well as any rabies vaccine that your pet might receive. In fact, federal regulations require any product or medical device that is to be injected into a human needs to be tested by LAL.

Scientists also believe that horseshoe crabs hold promise in developing anti-cancer products, too.

On the less glamorous side, horseshoe crabs are an important economic product. Commercial eel and whelk fishermen say nothing attracts these species to their traps like horseshoe crab bait. The fishing industry, which exports most of their catch to Asian markets, harvest millions of horseshoe crabs a year as bait. Researchers at the Delaware Biological Institute are trying to develop an artificial protein that can be manufactured that could substitute for the real thing.

The horseshoe crab is also considered to be a “key species” because many shorebirds, fish and invertebrates depend on their eggs for nutrition. When the horseshoe crabs come ashore during May and June, many species of birds time their northern migration to attend the event all along the coast of North America. Long Island is really on the map when it comes to horseshoe crab country. The SHU “Mark/Recapture study” is now in its 10th year. It focuses on the Long Island Sound area to understand more about the population ecology of the horseshoe crab and how it utilizes the Sound for survival and reproduction.

The educational instruction was just the first part of my horseshoe crab mission. Now that I had learned to tag the armor-plated creatures, I could begin my own personal horseshoe crab patrol on Smithtown Bay, near where I live. I figured I would wait until the next full moon, when according to Dr. Mattei, the horseshoe crabs would come up onto the beach in large numbers to spawn.

But on my little stretch of beach, the horseshoe crabs didn’t appear in mass on those nights, but rather showed up a few every day. Over several weeks I tagged 25 horseshoe crabs along a ¼ mile of beach front (who can ever figure those kilometers out?). Even during the new and full moons, I never experienced finding dozens and dozens on the beach all at once. Some days I tagged one or two. I never tagged more than four in a day and some days, none. It seemed that towards the end of June I saw more horseshoe crabs than in May. Perhaps a result of our rainy, cooler-than-usual spring.

I didn’t take the tagging responsibility lightly. Every morning I would rise a bit earlier to allow a short trip down to the beach with my equipment bag, just in case I had some customers, and then again at night when I got home from work.
One day as I walked on the beach in the early morning I made a sighting of a horseshoe crab I had tagged. It was like seeing an old friend.

“Hello number 189647!” I said. “It’s me, the crazy woman with the door stopper piercing tool.” His 10 eyes didn’t seem happy to see me. He quickly high tailed it for the open water.

At times when a stranger would appear on the beach, walking yards behind me, I hesitated to grab any horseshoe crab for tagging. Sure, I could defend what the heck I was doing pushing a door stopper into a horseshoe crab, if questioned, but I didn’t want to bother whipping out my official NYSDEC Limulus Tag and Release permit and explaining the whole thing.

“Sure, lady. And I’m Captain Ahab.”

And on June 16 when I used up my last tag, it was as if an underwater horseshoe crab “Twitter” had gone out—“No more tags left.”  As I started my walk back to my starting point I counted 14 potential participants that had come onto the beach probably knowing that I was out of tags. But I guess after being around for 455 million years, they pick up a trick or two.

For more information about horseshoe crab monitoring throughout New York,  visit Project Limulus’s Web site at www.projectlimulus.org or Cornell University Cooperative Extension Service and NYSDEC’s Web site at

http://www.nyhorseshoecrab.org/.

What To Do If I See One ?

Reporting crabs that have already been tagged is just as important as tagging, if not more so. This data allows researchers to know how many times crabs spawn each season and where. According to Graham, the local Long Island volunteers tagged over a thousand of horseshoe crabs this season. Keep an eye out for horseshoe crabs with yellow plastic spaghetti tags or white discs (see photo) attached to their side. Call 1-888-LIMULUS (1-888-546-8587) to report the unique number on each tag, what beach you found it on and if it was dead or alive.

If you go to http://www.projectlimulus.org  you can enter the information right online. The data you collect greatly benefits the Project Limulus study and the NYSDEC conservation efforts.