For the past 445 million years, horseshoe crabs have been in existence, pre-dating humans, dinosaurs and pretty much life as we presently know it. However, in the past 15 years their numbers have been dwindling and local nature lovers, conservationists and scientists are looking to find out why.
Sacred Heart University’s Project Limulus (the project takes its name from the scientific name for a horseshoe crab) is a horseshoe crab research project run by Jennifer Mattei, has been relying on the help of volunteer groups such as the Menunkatuck Audubon in Guilford, to search for, count, and tag horseshoe crabs on local beaches.
“Our goal is to find out how many horseshoe crabs there are, how many are returning to the area and have survived, and what their health is,” explained Deanna Broderick, a member of the Menunkatuck Audubon. She has been helping to organize the tagging expeditions in Guilford for the past seven years.
“We have definitely seen a decline in numbers and it’s very concerning,” Broderick said. “In fact, on three of our recent outings we found no crabs at all.”
This year the tagging “outings” began on May 11th. Typically the creatures are found up on the shore during the new and full moon cycles, at high tide, during the months of May and June. The females come up to the shore, the males clasp onto their backs, and when the females lay their eggs; the males swim over them and fertilize them.
According to Broderick, females are always larger than males and lay thousands of eggs at a time. The eggs hatch within two weeks and the juveniles (which look exactly like full grown horseshoe crabs just much tinier) swim off. They grow and molt six different times during their first year of life and at each molting, they fill their shell with water until it burst open and they crawl out.
“Horseshoe crabs really are fascinating creatures,” said Broderick, who was excited to find an eight year-old tagged crab this year, which was tagged previously in Branford.
“Horseshoe crabs don’t usually move much from one area,” explained Broderick, pointing out that during the colder months they just move further out in the ocean, but they do not migrate. However, their mating rituals are tied directly to some migratory bird flight paths.
As the waves lap the shores of Maryland beaches, the Red knot birds get ready for the fertilized horseshoe crab eggs to hatch so they can fest on the young ones. Without this food source, Broderick said, the birds would not survive.
“Its nature and its all tied together, so we have to make sure we do what we can to protect and preserve it,” Broderick urged. “These creatures aren’t furry or cute so sometimes it’s hard to get people to care about them, but what else is still around that we can touch, see and feel that is older than dinosourses?”
A number of scientists and conversationalists are pushing hard to have horseshoe crabs listed on the International Union of Conservation for Nature red listing, in hopes of adding an element of protection to this important creature, which is not really a crab at all. Instead, horseshoe crabs are arthropods, more closely related to spiders and scorpions. They have distinctly blue blood, which is harvested to test surgical instruments and intravenous drugs on to ensure they are safe. Their blood is a good detector of even the smallest traces of endotoxins.
According to Broderick, there is speculation that pollution, as well as over harvesting, is what has caused the horseshoe crab decline in numbers. In the past, fisherman in Connecticut could obtain a license to harvest the crabs to be used for bait, but those licenses are not longer given out, however a few old school fishermen do still have them and are allowed to use them. Brodrick believes however, that it’s not that small number that is affecting the crabs, but instead, the “yahoos” who harvest without licenses, because the crabs are free bait. She implores people to keep a look out for horseshoe crabs and protect them when possible.
“They are docile and harmless. They can’t sting or bite and if you see one flipped over, please help it flip right side up, but never grab it by its tale, it’s not meant to support its body weight and it will break off and they will not have any way to flip themselves if needed,” warned Broderick, who has become quite fond of the “sea spiders”.
If you come across a tagged horseshoe crab, dead or alive Broderick requests that you note the tag number, location and date and call 1-888-LIMULUS.
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