Horseshoe crabs are 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. During the high tide, horseshoe crabs come ashore to lay their eggs in sandy beach areas. Migratory shorebirds, like red knots which are listed as “threatened” under the US Endangered Species Act, stop and rest in the Delaware Bay region during this spawning period, and horseshoe crab eggs are an important food source for them on their long migrations. Horseshoe crabs are also harvested for use as bait in commercial fisheries for eel and conch, and their blood is collected to make Limulus Amoebocyte Lysate (LAL), a chemical that aids in the detection of human pathogens in patients, drugs, and intravenous devices.

Given Atlantic menhaden’s critical role in the marine ecosystem and commercial fisheries, the Commission invested considerable resources in developing an ecosystem model that ensures enough menhaden are left in the water coastwide to sustain not only the fisheries that target menhaden but also the key predators that rely on them.

Efforts to take into account menhaden’s role as a forage fish began in the early 2000s with the development of the multispecies Expanded Virtual Population Analysis (MSVPA-X) model. The Commission’s Ecological Reference Points (ERP) Work Group explored a suite of models to develop ERPs, ranging from very simple to very complex. The ERP Work Group ultimately recommended using the Northwest Atlantic Coastal Shelf Model of Intermediate Complexity for Ecosystems (NWACS-MICE) in combination with the single-species model to evaluate tradeoffs and set ERPs for Atlantic menhaden.

NWACS-MICE is a streamlined ecosystem model for Atlantic menhaden that includes Atlantic herring, bay anchovy, striped bass, weakfish, spiny dogfish, and bluefish. Using this model in combination with the single-species model, the Atlantic Menhaden Technical Committee, Stock Assessment Subcommittee, and ERP Work Group developed ecosystem-based reference points for menhaden that account for its role as a forage fish. ERPs were adopted for use in the management of Atlantic menhaden in August 2020 and since then have been used by the Atlantic Menhaden Board to set total allowable catch.

The ERP Work Group works to update the NWACS-MICE and other potential models every few years to ensure that the most recent data are being used to manage this important species. The next ERP update should be completed in 2025.
At the link below, scroll through photos and figures to better understand what ERPs are, how they are used in the management of menhaden, and how they work towards achieving ecosystem approaches to fisheries management.

ERP

MSVPA Documents

Other Resources

• NEFSC Ecosystem Considerations Website