ANNAPOLIS, Md.— A Maryland Circuit Court judge has sided with the Center for Biological Diversity and denied a motion seeking to dismiss its lawsuit arguing that the Maryland Department of Natural Resources should release its data on horseshoe crab deaths.

Judge Michael Wachs of the Maryland Circuit Court for Anne Arundel County denied the department’s motion to dismiss the Center’s Public Information Act lawsuit. The suit seeks state records on how thousands of horseshoe crabs are killed, bled or injured by pharmaceutical companies and fishermen annually. The ruling was issued late Friday.

“This is a good sign for both horseshoe crabs and the people of Maryland, who have a right to know about their government’s actions and behavior,” said William Snape, an attorney representing the Center. “Our next step is to convince the court that this crucial biological information about how horseshoe crabs are killed has to be released publicly.”

Horseshoe crabs are threatened with extinction, but because Maryland shrouds in secrecy the process it uses to determine when and how many crabs can be harmed, the Center and other parties cannot meaningfully participate in protecting the imperiled animals.

“The public needs to know how many horseshoe crabs are being slaughtered if these ancient animals are going to have a future,” said Will Harlan, a senior scientist at the Center. “It’s impossible to protect vulnerable animals without accurate information.”

Biomedical companies harvest horseshoe crabs and drain their blue blood, which is used to detect toxins in drugs and medical devices. Horseshoe crab blood harvests have virtually doubled since 2017, with nearly 1 million horseshoe crabs harvested for their blood in 2022.

Synthetic alternatives to horseshoe crab blood tests are already being used in Europe, but companies in the United States have been slow to adopt the synthetics.

Horseshoe crabs are brown, body-armored arthropods with 10 eyes and a long, spiked tail. Despite their intimidating appearance, they are completely harmless to humans. Each spring along the Atlantic coast, horseshoe crabs lay their eggs in massive beach spawning events.

Nearly twice as old as the dinosaurs, horseshoe crabs have been crawling ashore for more than 450 million years. In the past decades, however, horseshoe crab populations have declined steeply in all states, including Maryland.

Several horseshoe crab mass mortality events have occurred along the Atlantic coast in recent years. A 2021 horseshoe crab die-off in Ocean City, Maryland, resulted in thousands of horseshoe crabs clogging canals.

Mass horseshoe crab mortality events were observed in Ocean City again in 2022 and 2023. Another horseshoe crab die-off was reported at Brigantine Beach, Maryland, in 2022.

The Center and 23 conservation allies, including the American Bird Conservancy, Humane Society of the United States, and Maryland Ornithological Society petitioned the U.S. Fish and Wildlife Service earlier this year to protect horseshoe crabs under the Endangered Species Act.