BLUE BLOODS
An ancient species and modern human health
Each year, roughly 600,000 horseshoe crabs are plucked from local beaches and transported to biomedical laboratories, where researchers extract some 30-40 percent of their unique blue blood before returning them to the ocean. Horseshoe crab blood is the only known source of Limulus amebocyte lysate (LAL), a distinctive substance used to test all FDA-certified medical implants and pharmaceutical drugs and vaccines — including those being developed for COVID-19 — for dangerous endotoxins. Now, as pharmaceutical companies race to manufacture millions of doses of the new COVID-19 vaccines, they are looking to LAL to make sure the injections are safe. The question is: Will this put added pressure on the horseshoe crab population? The impact of blood harvesting on horseshoe crabs has been studied for decades by Win Watson, UNH professor emeritus of zoology. Most recently, in 2019, Watson, Meghan Owings ’17G and Chris Chabot from Plymouth State University published research that found the crabs spawn less often immediately after being returned to the water and remain in deeper water months after being bled instead of moving into shallow water to spawn. As it is, approximately 10 to 25 percent of the crabs that are bled do not survive. But Watson’s spawning data suggests that harvesting the crabs’ blood has farther-reaching and longer-term impacts on the crab population than had been previously known.
photo: Steve De Neef
It is tough to get a definitive answer from the pharmaceutical industry about whether or not the global demand for COVID-19 vaccines will mean an increase in the number of
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