Its not "just" a needle insertion. There's no measurement of how much blood is taken from each crab, so there's no way to know how much damage is done on an ind

Its not "just" a needle insertion. There's no measurement of how much blood is taken from each crab, so there's no way to know how much damage is done on an individual basis. Imagine any other animal bled this way (https://www.thedodo.com/horseshoe-crabs-blood-tests-1531014029.html https://www.thedodo.com/horseshoe-crabs-blood-tests-15310140...) and then "released" with claims of no harm done. I did field work to study horseshoe crabs' near-shore behavior as part of my master's work. Fortunately we weren't bleeding them.