We are so fortunate to have science-based programs that are easily accessible. Whether you are seeking educational programming for your children or for yourself, the Marion Natural History Museum offers that and so much more.
On July 24, Derek Perry, invertebrate biologist for the Massachusetts Department of Marine Fisheries, gave a presentation primarily geared towards adults on methods and the importance of data collection for the noble and ancient horseshoe crab.
Perry explained that one important aspect for the data collection and study is its rare, blue-colored blood used in medical research. There are 22 locations where population and nesting-site information is gathered along the eastern coast. From Delaware, home to a dense population, to locations throughout coastal Cape Cod north to Plymouth, volunteers painstakingly collect details.
But let’s for a moment take a quick peek at the animal itself.
Horseshoe crabs were roaming prehistoric shorelines as the great dinosaurs populated the planet. This mighty arthropod hasn’t changed much over the eons of its existence. Horseshoe crabs are chelicerates, making them closely related to arachnids like spiders, ticks and scorpions. They could be considered a marine spider.
Now consider that the animal has existed for 300,000,000 years, actually longer than the dinosaurs. It lives about 25 years, molting some 15 or more times during its life. They have nine eyes scattered around their armored body and light receptors in their tail. That tail, called a telson, is not a defensive weapon. It’s designed to help the creature flip back over if pushed onto its back. As for legs, it has 10; that allows it to walk on the seafloor.
The National Wildlife Federation reports, “Horseshoe crabs utilize different habitats depending on their stage of development. The eggs are laid on coastal beaches in late spring and summer. After hatching, the juvenile horseshoe crabs can be found offshore on the sandy ocean floor of tidal flats. Adult horseshoe crabs feed deeper in the ocean until they return to the beach to spawn. Many shorebirds, migratory birds, turtles, and fish use horseshoe-crab eggs as an important part of their diet. Horseshoe crabs are a keystone species within the Delaware Bay ecosystem.”
We were interested in the history of horseshoe crabs and medical use, which led to economics. Perry talked about the animal’s importance as a source of income for local fishermen. He talked about the regulations established to protect horseshoe crabs from being aggressively harvested, and he talked about the collection process used for siphoning its blood and the acceptable levels of mortality the industry allows in the process.
Part of that process includes the tagging of animals during the population counts, much of which is done on a voluntary basis, data which is critical not only for the horseshoe crabs’ continued survival but for the fisherman’s economic stability.
The collection process has a medieval quality. Long rows of animals are hung and bled. The blood is collected. There is an acceptable level of mortality. Yet the benefits outweigh those victims, according to long-established, scientific norms.
Lectures should always produce a desire to learn more. Perry’s presentation did just that. We found that horseshoe-crab blood is manufactured into a substance called limulus amebocyte lysate or LAL, which can detect harmful pathogens in critical medicines.
Because much of the data collected is voluntarily submitted, exact figures are nearly impossible to verify, but approximately 15% of all horseshoe crabs used in the blood-collection process don’t survive the procedure.
There is good news on the horizon, however; synthetic forms of blood are being developed. The wild harvesting may eventually not be needed to ensure that humans are being medically treated with safe chemicals. The living fossils may once again enjoy their peaceful coexistence with humans minus the 21st century bloodletting.
To learn more about Natural History Museum programing, visit marionmuseum.org.
By Marilou Newell