Each year in early summer, thousands of horseshoe crabs emerge from the waters of the Delaware Bay to spawn.
The eggs are vital for shorebirds, in particular red knots, which stop along the New Jersey coast as they migrate from South America to Canada.
Horseshoe crabs are also valuable to biomedical companies, which use their blood to test vaccines, medicine and implants, ensuring that they are safe for humans.
Conservation groups and the federal government agencies disagree over how horseshoe crabs should be managed and protected.
In 2024, citing steep decline in population, nearly two dozen organizations petitioned the National Marine Fisheries Service division of National Oceanic and Atmospheric Administration (NOAA) to add the American horseshoe crabs under the Endangered Species Act. In January 2026, two groups – the Center of Biological Diversity and Friends of Animals – sued the NOAA Fisheries for failing to make a decision.
“Horseshoe crabs have saved so many people, and now it’s up to us to pay back that debt and save them,” Will Harlan, a senior scientist at the Center for Biological Diversity said in a statement. “We could lose these living fossils forever if they don’t get Endangered Species Act protections soon.”
This February, NOAA released a finding that found that although red knots, which depend on crab eggs are a threatened species, the horseshoe crabs themselves are not.
“The petitions do not present substantial scientific or commercial information indicating that the petitioned actions may be warranted,” the agency concluded.
History of harvesting horseshoe crabs
Horseshoe crabs are some of the oldest creatures on the planet, pre-dating the dinosaurs.
Along the Delaware Bay in New Jersey, humans have been harvesting them in large quantities since it was settled by Europeans.
Farmers used them as livestock feed and fertilizer, and the commercial fishing industry has used them as bait.
Since the 1970s, biomedical companies have used horseshoe crabs for their blood, which contains a protein called Limulus Amebocyte Lysate, that can be used to detect bacteria and toxins. Anything that enters a human system during a medical procedure and can cause infection – surgical devices, drugs and vaccines – has likely been tested using horseshoe crabs.
Because of human harvesting, as well as pollution and habitat loss, horseshoe crab populations have declined 90%, scientists say.
As a result, New Jersey adopted a moratorium on harvesting and possession of crabs in 2008, except for biomedical companies, which are allowed to bleed a portion of their blood and then must return them to the wild.
But conservation groups and scientists argue the industry is not properly regulated and laws are not enforced. They estimate that between 15%-30% of harvested crabs die during or after the bleeding process.
State laws also vary by location along the coastline, some permitting hundreds of thousands to be harvested each year.
The future for horseshoe crabs
In its response to calls to provide federal protection, NOAA cited statistics that found the horseshoe crab populations are generally stable along the Atlantic Coast from Maine to Florida – depending on the study and the location.
It concluded that “sufficient information is not provided or otherwise available to indicate that the harvest and collection mechanisms identified by the petitions may cause the species to become endangered or threatened with extinction.”
Advocates argue the agency did not go through the proper scientific and public process.
“One of the biggest mistakes it made was to cherry-pick its own evidence and data to support its decision, without first allowing for public notice and public comment during its consideration of whether to list the species,” said Danny Waltz, the Center for Biological Diversity’s Southeast Program Senior Attorney.
While conservation groups continue their battle to change laws and designations, the future of the horseshoe crab is also dependent on new biomedical technologies.
Human-made alternatives to horseshoe crab blood have been in use in Europe since 2020. In May 2025, Pharmacopeia, approved synthetic alternatives in the U.S. and found it to be just as effective.
But the market for horseshoe crab blood remains lucrative – one crab can yield as much as $1,800 – and some in the industry have been reluctant to change.
As a result, advocates argue, horseshoe crabs need federal protection.
“NOAA has an obligation to rely on the best available science in making listing decisions and should reconsider its decision not to list the Atlantic horseshoe crabs,” said Jennifer Best, director of the Friends of Animals Wildlife Law Program.
