Horseshoe crabs spawn with wild abandon as state rolls out new protections

May 31, 2024
Barbara Moran



Horseshoe crabs during breeding season in Orleans. (Jesse Costa/WBUR)

Horseshoe crabs are not endangered or threatened in Massachusetts, but their numbers are at historic lows. To protect the species, state wildlife officials are rolling out new regulations. As of 2024, horseshoe crabs can no longer be harvested in Massachusetts during spring spawning season, from April to June.

The state's horseshoe crab population has declined for several reasons, according to Mark Faherty, science coordinator for Mass Audubon's Wellfleet Bay Wildlife Sanctuary. For decades they were considered pests; kids on Cape Cod could get a couple of pennies for each crab they killed — tossing it in the dunes to die and snapping off its tail as proof for town officials. "They were worth more dead than alive," Faherty said.

Today, horseshoe crabs are harvested for bait in the whelk fishing industry, and for use by biomedical companies. A protein in their pale blue blood is used in a test for bacterial toxins in medical products.

But they are also valuable players in coastal ecosystems. Horseshoe crab eggs, especially, are a vital food source for migrating shorebirds like the near-threatened red knot.

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