Project Limulus: Understanding and Conserving a Critical Natural Resource
Dr. Jennifer Mattei is a woman on a mission, and she’s determined to reach her goal even if she has to slosh through salt marshes, traverse towering sand dunes and muck around in mud up to her waist. In fact, Mattei, associate professor of Biology and director of Sacred Heart University’s Professional Science Master’s program, wouldn’t have it any other way.
Mattei, fellow SHU associate professor of Biology, Dr. Mark Beekey, and many other devoted biologists and conservationists are deeply committed to studying and preserving Limulus polyphemus – the American horseshoe crab. The horseshoe crab’s traditional migratory region and breeding territories spread from the coasts of southern Maine to Florida.
A concerted effort is now under way to locate, count and tag horseshoe crabs – whose numbers have declined since the early 1990s. The crabs are considered to be both a dominant and a “keystone” species of the intertidal zone because of the tremendous numbers of shorebirds, fish and invertebrates that rely on their eggs and larvae for nutrition. It has been reported that as the horseshoe crab population declines, so do the populations of species that rely on them.
In addition to their ecological value, horseshoes crabs are worth millions of dollars to commercial fishermen who use them as bait to harvest eel and conch, which are mainly exported and sold in Asian markets. But their greatest value to humankind, beyond the squeals of children along East Coast beaches, is that the blood of Limulus has an amazing property: It contains unique blood cells (amebocytes) that are used to test human vaccines for bacterial contamination. If the amebocytes come into contact with bacteria or their toxins, they attack it. Scientists in the 1950s first identified this significant feature and developed the horseshoe crab blood derivative called Limulus Amebocyte Lysate (LAL).
Today, federal law requires any medical device or product that will be inserted or injected into a human body to be tested for bacterial contamination using LAL. For example, each year pharmaceutical companies produce new flu vaccines and use LAL to test them for bacterial contamination. If a batch is found to be contaminated, it is thrown out. The LAL test also is required for veterinary practices to avoid contaminated rabies vaccines. And NASA supplies astronauts in space with LAL to swab a sore throat to determine if it might be a bacterial or viral infection that requires antibiotics. Additionally, researchers are focusing on other Limulus blood components to help develop potential anti-cancer medicines.
Millions of horseshoe crabs spawn on the shores of New Jersey, Delaware, Maryland and Virginia, usually starting in mid-May through June. Thousands of them are tagged every year using uniquely numbered, white disc tags provided by the U.S. Fish and Wildlife Service. The information on the tags can then be collected during subsequent annual surveys to track migration and to determine the most important spawning habitats.
Project Limulus focuses on the horseshoe crab population found in Long Island Sound. Mattei, Beekey and other associates dedicated to conserving the horseshoe crab, venture out to locate, count and tag these gentle creatures in Connecticut and New York. Often they are accompanied by Sacred Heart University students, as well as students from other schools that use these field trips as “learning labs” and participate in the search and tracking process.
“We want to teach students and volunteers that no other animal on earth has contributed more to human health and wellbeing than the horseshoe crab. They learn that LAL keeps our vaccines safe, and at the same time Limulus is an integral part of the Long Island Sound ecosystem,” Mattei explains. “It’s an intricate, interconnected system, and the demise of this valuable species would have far-reaching effects. We work with students, community groups, volunteers and other scientists in our research program and are trying to educate as many people as possible to generate support and understanding about horseshoe crab conservation and the importance of their survival.”
Project Limulus is currently funded by a grant from the Disney Worldwide Conservation Fund, with the goal to support wildlife conservation projects that involve local community members. Additional funding comes from the College of Arts and Sciences, Undergraduate Research and Internship program and CT Sea Grant. Project Limulus has partnerships with more than 15 nonprofit conservation organizations, including the Connecticut Audubon Society, The Maritime Aquarium and The Nature Conservancy.
Biology majors at SHU can apply for a research assistantship and are required to take ecology. Mattei tries to get the students out into the environment as often as possible, visiting not only the shore, but also forests, rivers and ponds to study Connecticut’s diverse habitats. “Most of our bio majors love our field trips,” Mattei adds, “and students adjust quickly, even if they have to learn the hard way that flip-flops and high heels aren’t appropriate footwear for this kind of work!”
One alumnus of the Biology Department, Adam Rudman, is now an adjunct biology instructor at Sacred Heart, and in the summer serves as the full-time outreach coordinator of Project Limulus. He conducts field trips for school groups and volunteers with the help of undergraduate research assistants and also leads educational workshops and community seminars.
“I love seeing kids of all ages out handling the horseshoe crabs, learning how to use a seine net and just exploring the beach,” Rudman says. “I always spent a lot of time on the beach as a kid, and those experiences led me to fall in love with biology and eventually become a biologist.
“Through this program, students have a real hands-on learning experience that I believe gives them a personal insight that can be life changing. We’ve already worked with more than a thousand students, thanks to the Disney grant. If I could get every K-12 student in Connecticut to hold a horseshoe crab, they would get that direct connection to the crabs and to the Long Island Sound ecosystem which, ultimately, benefits everyone and everything.”
That sentiment is echoed by Matt Cole, a SHU sophomore and Project Limulus volunteer. “The students who work with us or visit on field trips actually receive much more than just a greater understanding of the marine environment,” Cole observes. “They leave the beach or classroom with knowledge of the interconnectedness and co-reliance among various species and, more importantly, humans to animals. Hopefully, after this inspiration, students will take extra care to protect our earth and all of the creatures coexisting with us.”
For more information on Project Limulus, email Mattei, Beekey or Rudman at email@example.com, or visit their website, www.projectlimulus.org.