Last year my boyfriend and I signed up to be research volunteers for the Maritime Aquarium horseshoe crab tagging program. What inspired me to join the tagging force was curiosity, and my slight fear of the strange, Darth Vader-looking creatures that I’ve harbored since childhood. I had hoped that by getting up close to the crabs that I would learn to love them, and in many ways I have.
More closely related to spiders than crabs, horseshoe crabs existed as far back as 450 million years ago, but we still know little about them today.
What we do know is, their population continues to dwindle each year, especially on the East Coast. This is primarily caused by habitat destruction and over harvesting.
Although they are sometimes used as bait, horseshoe crabs are mainly harvested for their copper and amebocyte-rich blood, used in medicines and vaccines and to prevent bacterial infections. While this may be helpful for modern medicine, the declining population not only affects horseshoe crabs, but other wildlife, such as red knots and other waterfowl as well.
So, this is where we come in. From mid May – early July, the volunteers and Maritime staff, along with Dr. Jennifer Mattei, an environmental scientist at Sacred Heart University, take to Calf Pasture Beach in Norwalk, CT late at night (usually 11pm – 1am) during new and full moons, when the crabs come up to shore to spawn.
Our first job is to locate the crabs along the shore and in the water. Next, we identify their gender, which is done by looking at its size – males are typically smaller than females – and, turning it over and observing its appendages – males have a “boxing glove” on their front appendage, while females have a pincer. After identifying them, we use what I can only describe as a shiv to puncture a hole in the side of its shell and put a census tag in its place.
Once this is complete, we take a quick measurement of the crabs, release them, and move on to the next set. The ultimate goal of this census is to establish a baseline population, track their migrations and, hopefully, restore the horseshoe crab population.
The best thing you can do for the study is if you find a tagged horseshoe crab on the beach, make sure you call it in. You will find the phone number on the tag, along with the crab’s tracking number. And, don’t worry – although they look menacing, they are gentle creatures and are completely harmless.
If you’re interested in becoming a tagging volunteer, contact your local aquarium.