The Horseshoe Crab has light blue, copper-based blood.

2013 marked the first year the Horseshoe Crab Management Board used the Adaptive Resource Management (ARM) Framework to set horseshoe crab harvest levels for the Delaware Bay area. The ARM Framework, established through Addendum VII (2012), incorporates both shorebird and horseshoe crab abundance levels to set optimized harvest levels for horseshoe crabs of Delaware Bay origin. For the 2016, 2017, and 2018 fishing seasons, harvest in the Delaware Bay area has been limited to 500,000 male horseshoe crabs and zero female horseshoe crabs. This total harvest is allocated among the four states that harvest horseshoe crabs from the Delaware Bay crab population (New Jersey, Delaware, Maryland, and Virginia). The allocation is based upon multiple decision options, including the proportion of horseshoe crabs harvested that originate from Delaware Bay and the allowance for additional male harvest by Virginia and Maryland to compensate for protecting females when the ARM harvest output includes a moratorium on female crabs. Since 2008, New Jersey has had a moratorium on horseshoe crab harvest despite its allocation of the Delaware Bay origin horseshoe crab quota.

Reproduction: Horseshoe Crabs hatch from eggs that the female lays.

The Horseshoe Crab: Natural History, Anatomy, …

Horseshoe Crabs - Delaware & Maryland - Beach-Net

Horseshoe crabs (Limulus polyphemus) are a marine arthropod found along the Atlantic coast from northern Maine to the Yucatan Peninsula and the Gulf of Mexico. The Delaware Bay supports the largest spawning population in the world. Adults either remain in estuaries or migrate to the continental shelf during the winter months. Migrations resume in the spring when the horseshoe crabs move to beach areas to spawn. Juveniles hatch from the beach environment and spend the first two years in nearshore areas.

10 Hard-Shelled Facts About Horseshoe Crabs | Mental …

Once called "Horsefoot Crabs" because of the resemblance of its shell to a horse hoof, the Horseshoe Crab isn't really a crab. Related to scorpions, ticks and land spiders, horseshoe crabs have their own classification (Class Merostomata).

The Horseshoe Crab is up to 2 ft (60 cm) long and weighs up to 10 pounds (4.5 kg); it molts its skin many times as it grows.
The Horseshoe Crab first appeared about 500 million years ago (during the Ordovician Period), and has changed very little since.

“Can you eat horseshoe crab?” | Helen Cheng

Horseshoe crabs, common along the Delaware coast, have evolved little in the last 250 million years. Still, they have survived because of their hard, curved shells, which have made it difficult for predators to overturn them and expose their soft, vulnerable underbellies. The horseshoe crab has also survived because it can go a year without eating and endure extreme temperatures and salinity.

A close-up view of spawning horseshoe crabs. Photo credit: Dr. Rob Robinson, British Trust for Ornithology.

horseshoe crabs - Atlantic States Marine Fisheries Commission

In October 2017, the Board approved terms of reference, including tasks specific to the horseshoe crab stock assessment, such as assessments of regional populations of horseshoe crabs, incorporation and evaluation of estimated mortality attributed to the biomedical use of horseshoe crabs for Limulus Amebocyte Lysate production, and comparisons of assessment results within results from the ARM Framework. The results of these assessments are expected to be presented to the Board in October 2018.

Anatomy: The Horseshoe Crab has a hard outer shell (an exoskeleton), 5 pairs of jointed legs and a pair of pincers.

The American horseshoe crab is a common sight on Florida's beaches

Horseshoe crabs are managed under the Interstate Fishery Management Plan for Horseshoe Crab (1998) and its subsequent addenda (Addenda I-VII). Under Addendum I (2000), the Commission established state-by-state quotas in all Atlantic states for horseshoe crabs harvested for bait. Addendum II (2001) allows voluntary transfers of harvest quotas between states to alleviate concerns over potential bait shortages on a biologically responsible basis, with Commission approval. Addendum III (2004) reduced harvest quotas, implemented seasonal bait harvest closures, and revised monitoring components. In response to decreasing migratory shorebird populations, Addendum IV (2006) reduced quotas in New Jersey and Delaware and added additional protection in Maryland and Virginia to increase horseshoe crab and egg abundance in and around Delaware Bay. Addenda V and VI extended Addendum IV’s measures through 2012.