Horseshoe crabs in the Long Island Sound may be headed for extinction, study finds

A new study looking at horseshoe crabs in the Long Island Sound confirms the ancient creatures face potential extinction. 

The threat stems from climate change, loss of habitat, and overharvesting. 

Horseshoe crabs are neither cute nor cuddly, but they are a crucial part of the Long Island Sound's ecosystem. Despite their name, horseshoe crabs are not crabs, or even crustaceans. They're related to spiders, and they're harmless. They can't bite, sting, or pinch. They've existed for 450 million years.   

Migratory birds feast on their eggs, and horseshoe crab digging amplifies the nutrient cycle. 

"This is an animal that plays an important link between these different habitats, from the shallow water to the deep," Dr. Sarah Crosby of the Maritime Aquarium in Norwalk said. 

Crosby conducts research on the creatures, and contributed to the study, which notes horseshoe crab populations in the Long Island Sound are declining 2-9% per year. 

"We're becoming increasingly concerned about the decline because, despite some efforts to protect them better, we're continuing to see the population get smaller and smaller," Crosby said. 

Connecticut banned most harvesting of horseshoe crabs in 2023, but New York allows up to 150,000 to be captured in 2025 for use as fishing bait. 

Horseshoe crab blood is valuable for testing pharmaceuticals. Advocates say that can be phased out in favor of a new, synthetic alternative. 

"For many years, it was sort of a necessary evil, right, for the good of people. But now that this alternative to the horseshoe crab blood exists, we're really encouraged to see some companies starting to switch over, so they don't need horseshoe crab blood anymore. And they can keep those animals in the water where they belong," Crosby said.

Researchers and volunteers will continue to monitor horseshoe crabs, and advocate for protections to rebuild the diminished population. 

A spokesperson for the New York State Department of Environmental Conservation told CBS News New York the "DEC has and will continue to balance the sustainable use of horseshoe crabs in New York with the conservation of their populations."

A source in state government said DEC believes the situation is not as dire as the study indicates, and there is evidence of increased spawning activity in horseshoe crab populations in parts of the Long Island Sound.