Journal: BioScience
Location: Delaware Bay, USA

In the 1990s, there was a 90% decline in horseshoe crab (Limulus polyphemus) egg availability due to a 10-fold increase in harvesting for bait, resulting in a decline in body weight of their predator the red knot (Calidris canutus rufa), which congregates in the Delaware Bay every May to feed on the eggs. Between 1997 and 2007 red knots declined by 75%, and the proportion weighing more than 180g by their usual departure from the Bay (26th-28th May) decreased from 0.6-0.8 to 0.14-0.4. The horseshoe crab harvest has continued to increase despite restrictions, and red knots are not recovering.

Niles LJ, Bart J, Sitters HP, Dey AD, Clark KE, Atkinson PW, Baker AJ, Bennett KA, Kalasz KS, Clark NA, Clark J, Gillings S, Gates AS, González PM, Hernandez DE, Minton CDT, Morrison RIG, Porter RR, Ross RK, and Veitch CR, 2009. “Effects of Horseshoe Crab Harvest in Delaware Bay on Red Knots: Are Harvest Restrictions Working?” BioScience 59(2):153-164.
Affiliations: Conserve Wildlife Foundation of New Jersey; USGS Forest and Rangeland Ecosystem Science Centre; International Wader Study Group Bulletin; New Jersey Division of Fish and Wildlife; British Trust for Ornithology; Royal Ontario Museum; Delaware Division of Fish and Wildlife; Fundacion Inalafquen; Richard Stockton College; Victoria Wader Studies Group; Carleton University; Canadian Wildlife Service; The Shorebird Project.

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