Keeping tabs on the local population

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