The Atlantic States Marine Fisheries Commission’s (ASMFC) Horseshoe Crab Management Board has approved a measure that will support regulators’ plans to establish and manage male-only harvests of horseshoe crabs.
The pharmaceutical industry prizes horseshoe crab blood for use in biomedical testing because of its ability to clot when exposed to bacterial toxins. The crabs are primarily caught and bled to support that industry, although they are also harvested as bait.
However, harvesters are only allowed to catch male crabs. Regulators have long maintained a ban on harvesting female crabs; conservationists groups claim Endangered Species Act (ESA) listed shorebirds like the red knot rely on horseshoe crab eggs for sustenance.
That decade-old ban was almost overturned last year, when the computer model regulators rely on to set harvest levels recommended a harvest of 175,000 female crabs in the Delaware Bay in 2025. After deliberating, the Atlantic States Marine Fisheries Commission sided with conservations and denied a female crab harvest, authorizing only a male crab harvest.
“The decision to once again protect female horseshoe crabs from the bait harvest offers another reprieve for Delaware Bay,” New Jersey Audubon Vice President of Research and Monitoring David Mizrahi said at the time. “It will pay dividends for the greater ecosystem, especially for red knots and other migratory shorebirds.”
In announcing its decision, the commission noted that it needed to update its computer model and adopt a new solution that allows regulators to set multi-year harvest specifications that exclude female crabs.
Now, the Horseshoe Crab Management Board has approved Addendum IX, which will enable them to set male-only harvests for up to three years until 2031.
“It also establishes a method for managing male-only harvest limits during multi-year specifications periods, reestablishes seasonal harvest restrictions, and clarifies policy related to harvest caps for Maryland and Virginia,” ASMFC noted in a release.
Addendum IX also includes a mandatory closure of the Delaware Bay region harvest from 1 January through 7 June.
Meanwhile, horseshoe crab harvesters are facing a petition from conservationists seeking to have horseshoe crabs ESA listed. Conservation groups are also pressuring the pharmaceutical industry to utilize synthetic blood for testing, instead of relying on bleeding horseshoe crabs. Earlier in May, the Center for Biological Diversity released a new scorecard to rank pharmaceutical companies’ efforts to transition away from using horseshoe crab blood.
Synthetic alternatives to horseshoe crab blood have been used in Europe since 2020, but the U.S. Pharmacopeia only recently developed new biomedical standards accepting the use of those synthetic replacements.