Sustaining Horseshoe Crabs and Supporting Migratory Shorebirds in the Delaware Bay
USGS is developing predictive models to inform sustainable harvest of horseshoe crabs (Limulus polyphemus) in Delaware Bay to help managers make decisions to support needs of people and shorebirds including rufa red knot (Calidris canutus rufa).
What is the Issue?
Both people and migratory shorebirds depend on healthy horseshoe crab populations in the Delaware Bay. People harvest horseshoe crabs for bait and a unique compound in their blood which is used worldwide to test for bacterial contamination of drugs and medical devices, a process also known as Limulus amebocyte lysate (LAL) testing. Migratory shorebirds, including species experiencing population declines, are dependent on horseshoe crab eggs to fuel their annual migrations.
What is at stake?
The Delaware Bay supports the largest spawning population of horseshoe crabs in the world and the second largest population of migrating shorebirds in North America. Sustainable harvest of horseshoe crab populations is needed to provide sufficient horseshoe crab eggs to support population recovery goals for Delaware Bay shorebirds. Horseshoe crab eggs are a vital source of food for species like the rufa red knot, which is listed as a threatened species under the Endangered Species Act.
What is our approach?
Developing and implementing predictive modeling for adaptive management of horseshoe crabs and shorebirds in the Delaware Bay will help inform managers’ decisions and actions. Specifically, USGS will:
- Develop multi-species predictive models that link horseshoe crab and shorebird dynamics to management alternatives and compare historic data.
- Analyze and estimate red knot passage population at the Delaware Bay each year by using mark-resight techniques and estimate horseshoe crab population size each year.
- Predict and identify consequences relevant to current management decisions and identify state-dependent management actions.
What are the benefits?
Changes in horseshoe crab harvest may affect the recovery of migratory shorebirds that depend on horseshoe crab eggs for food. This research will help us gain a better understanding of relationships between horseshoe crab and shorebird populations and ultimately will help managers find ways to:
- Sustain horseshoe crab population levels.
- Provide critical food resources for dependent species, migratory shorebirds in particular.
- Allow harvest of horseshoe crabs for bait.
- Provide continued use of horseshoe crabs to support testing for bacterial contamination of drugs and medical devices.
USGS is developing predictive models to inform sustainable harvest of horseshoe crabs (Limulus polyphemus) in Delaware Bay to help managers make decisions to support needs of people and shorebirds including rufa red knot (Calidris canutus rufa).
What is the Issue?
Both people and migratory shorebirds depend on healthy horseshoe crab populations in the Delaware Bay. People harvest horseshoe crabs for bait and a unique compound in their blood which is used worldwide to test for bacterial contamination of drugs and medical devices, a process also known as Limulus amebocyte lysate (LAL) testing. Migratory shorebirds, including species experiencing population declines, are dependent on horseshoe crab eggs to fuel their annual migrations.
What is at stake?
The Delaware Bay supports the largest spawning population of horseshoe crabs in the world and the second largest population of migrating shorebirds in North America. Sustainable harvest of horseshoe crab populations is needed to provide sufficient horseshoe crab eggs to support population recovery goals for Delaware Bay shorebirds. Horseshoe crab eggs are a vital source of food for species like the rufa red knot, which is listed as a threatened species under the Endangered Species Act.
What is our approach?
Developing and implementing predictive modeling for adaptive management of horseshoe crabs and shorebirds in the Delaware Bay will help inform managers’ decisions and actions. Specifically, USGS will:
- Develop multi-species predictive models that link horseshoe crab and shorebird dynamics to management alternatives and compare historic data.
- Analyze and estimate red knot passage population at the Delaware Bay each year by using mark-resight techniques and estimate horseshoe crab population size each year.
- Predict and identify consequences relevant to current management decisions and identify state-dependent management actions.
What are the benefits?
Changes in horseshoe crab harvest may affect the recovery of migratory shorebirds that depend on horseshoe crab eggs for food. This research will help us gain a better understanding of relationships between horseshoe crab and shorebird populations and ultimately will help managers find ways to:
- Sustain horseshoe crab population levels.
- Provide critical food resources for dependent species, migratory shorebirds in particular.
- Allow harvest of horseshoe crabs for bait.
- Provide continued use of horseshoe crabs to support testing for bacterial contamination of drugs and medical devices.