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DELAWARE ESTUARY SCIENCE CONFERENCE 2007

DELAWARE ESTUARY SCIENCE CONFERENCE 2007. Limulus polyphemus. THE IMPORTANCE OF ALTERNATIVE HABITATS TO SPAWNING HORSESHOE CRABS ( LIMULUS POLYPHEMUS ) IN LOWER DELAWARE BAY, NJ.

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DELAWARE ESTUARY SCIENCE CONFERENCE 2007

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  1. DELAWARE ESTUARY SCIENCE CONFERENCE 2007 Limulus polyphemus

  2. THE IMPORTANCE OF ALTERNATIVE HABITATS TO SPAWNING HORSESHOE CRABS (LIMULUS POLYPHEMUS) IN LOWER DELAWARE BAY, NJ Robert E. Loveland, Department of Ecology, Evolution & Natural Resources, Cook College, Rutgers University, New Brunswick, NJ 0890; and Mark L. Botton, Department of Natural Sciences, Fordham University, 113 West 60th Street, New York, NY 10023.

  3. Support for the major portion of this talk came from grants in 2001 from N J Marine Sciences Consortium, Sea Grant Program, and Army Corps of Engineers. We wish the thank all of the students at Rutgers and Fordham who helped in the field and lab. Also, we are grateful to the Haskin Shellfish Laboratory which provided logistic support for this study.

  4. Estimating egg density • Surface egg density was derived from 5 cm deep sample pits. Eggs at the surface are an immediate food resource for shorebirds. • Deep egg density was derived from a series of 20 cm cores. Eggs at depth are an index of horseshoe crab spawning. • Data in this presentation represent the mid-beach area, which has previously been shown to have highest egg density along the sample transect.

  5. Physical characteristics of open beaches and alternative habitats: • Linear measurements of each type of habitat were compiled using GPS readings • Beach width and slope • Depth to peat layer • Sediment water content, organic carbon content, and grain size

  6. Summary and Conclusions • Although the alternative habitats reviewed represent a relatively minor proportion of the overall shoreline, sandbars and tidal creeks appear to be “hot spots” for spawning horseshoe crabs and foraging shorebirds. • Habitats such as protected or bulkheaded, overwash, or erosional beaches, will still attract spawning horseshoe crabs provided these areas are composed of well drained, aerobic, deep sands. • Alternative habitats, particularly sandbars and tidal creeks, deserve high priority in discussions of horseshoe crab and shorebird management schemes.

  7. PAU AMMA! From Rudyard Kipling’s “Just So Stories”

  8. THANK YOU! ANY QUESTIONS?

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