When Katherine and I were in Provincetown, one of her Uncle Bob’s other guests was a physician named Justin. He told us a story about a friend of his who’d been diving and seen a horseshoe crab with a numbered tag. The diver took a picture and looked up the code. It turns out that Horseshoe Crabs are tagged to learn about migration patters, distribution and abundance along the East Coast.
During our walk on a beach across the harbor from Provincetown, I turned over any Horseshoe Crab I found to see if there was a code. I wasn’t really expecting to find any, but…
WOW! There it was!
I took photos, including a closeup of the tag so that I could report it later.
As soon as I was at my computer, I googled “Horseshoe Crab tagged.” I found the page where I could submit information about the crab I’d found.
I submitted the information on August 16 and received a response in the mail about a week or so later: a Certificate of Participation and a pewter Horseshoe Crab pin. I loved it!
The certificate said the crab had been released July 14, 1999 at Chatham, North Sound, MA. So, it had been alive for more than twenty-two years before washing up on that beach near Long Point. From Katherine and my research that seems to be about as long as they can live. Katherine and I didn’t see any trauma on the crab so it may have died of old age.
Why do we track Horseshoe Crabs, anyway?
Horseshoe Crabs have an important ecological role. Each female can produce tens of thousands of eggs, many of which end up as food for the millions of shorebirds who journey each year along the Atlantic Flyway from South American to the Arctic.
Additionally, Horseshoe Crabs are used for bait in the conch and American eel fisheries on the Atlantic Coast.
And, “[of] all marine species, Horseshoe Crabs have contributed the most to medical and physiological research,” according to the U. S. Fish & Wildlife Service. We learned about human vision from studying cells in the Horseshoe Crab’s eyes. Additionally,
“Pharmaceutical companies also harvest horseshoe crabs to extract their blue, copper-based blood which contains a chemical substance, hemocyanin, which clots when exposed to bacteria. The blood is used to test drugs and medical equipment for the presence of harmful bacteria.”
(From Maryland Fish and Wildlife Conservation Office.)
In 1998, the Atlantic States Marine Fisheries Commission developed a Horseshoe Crab Management plan. Parts of the plan included tagging the crabs, restrictions on harvesting, and creating a sanctuary off the mouth of Delaware Bay.
There is a lot more information about Horseshoe Crabs (including the fact that they are not actually crabs). For example, an alternative to Horseshoe Crab blood has been developed and is in use in other countries but not as much in the United States. Read more about rFC here in the Wikipedia entry about Horseshoe Crabs. I encourage you to click on the links and read more.
In my next post, I’ll have photos of the new birds I identified during our Provincetown trip. Stay tuned!