Horseshoe Crab Surveys

Horseshoe crabs are at least 300 million years old as a species. During May and June males and females gather on sandy beaches along the U.S. east coast to mate and lay eggs. The number of horseshoe crabs appearing on these beaches is declining and this may have serious consequences on species that depend on the horseshoe crab life cycle (migrating birds are the biggest concern). Humans use horseshoe crab blood to produce a substance that detects bacterial contamination in medecines and surgical equipment.

Each year, volunteers head out at high tides around the full and new moons in April, May and June to count horseshoe crabs along the east coast. The MMA is responsible for Monomoy beach while the UMass Field Station surveys the field station beach and the Nantucket Conservation Foundation surveys Eel Point. All data is submitted to a regional office for processing. We are always looking for volunteers to help with the surveys!

If you have questions about horseshoe crabs on Nantucket, feel free to email our aquarium director at!


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