Every year, during the months of May and June, about 50 crabs are tagged on Block Island by the members of The Nature Conservancy.
Horseshoe crabs are tagged by drilling a small hole into the shell and snapping a tag in.
Horseshoe crabs are interesting creatures. They’ve existed for over 430 million years. Their blood has a heavy copper content, which gives it a blueish tone. Their blood does not flow through veins, but freely throughout their bodies, and is a powerful protector against infection.
Why do we tag horseshoe
Read more on the Block Island Times website