This will hopefully come to an end soon though since researchers have now found a way to synthetically produce the molecule that made horseshoe crab blood so valuable
"The most obviously unusual aspect of crab blood is that it is bright blue, a consequence of using copper-based hemocyanin to transport oxygen where vertebrates use iron in hemoglobin. Instead of white blood cells to fight infection, many invertebrates have amebocytes, and Atlantic horseshoe crabs (Limulus polyphemus) have evolved these to such a peak of refinement that they are of enormous medical value.
Horseshoe crab amebocytes coagulate around as little as one part in a trillion of bacterial contamination. Even better, the reaction takes 45 minutes, not two days as with mammalian equivalents. Coagulan, the chemical that makes this possible, is used for testing medical equipment and vaccines prior to use, without which many more people would die from infections." - iflscience,com/plants-and-animals/how-horseshoe-crab-blood-saves-millions-lives/
A system/process/organization in Maryland raises and farms horseshoe crabs. The crab has very little blood, just a few drops. The process removes a drop or two not hurting the crab. Only a few drops at a time explains the cost. In addition to, the crabs die on full moons after reproducing ... Leaving 100s of empty floating shells that look like a broken bucket. Last fun fact, the horseshoe crab is WAY older than the dinosaurs. They will be here long after us
Horseshoe crab amebocytes coagulate around as little as one part in a trillion of bacterial contamination. Even better, the reaction takes 45 minutes, not two days as with mammalian equivalents. Coagulan, the chemical that makes this possible, is used for testing medical equipment and vaccines prior to use, without which many more people would die from infections." - iflscience,com/plants-and-animals/how-horseshoe-crab-blood-saves-millions-lives/