Spatial and temporal overlap between foraging shorebirds and spawning horseshoe crabs (Limulus polyphemus) in the Cape Romain-Santee Delta Region of the U.S. Atlantic coast

Takahashi, Fumika; Sanders, Felicia J.; Jodice, Patrick G. R.

doi:10.1676/21-00009

Cited by 3 publications

(3 citation statements)

References 35 publications

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“…Female crab abundance at Delaware Bay has thus been shown to positively correlate with an individual's ability to reach this body mass threshold and survive to subsequent years (Baker et al 2004). Recent results from the Cape Romain National Wildlife Refuge in South Carolina indicate a similar positive correlation between horseshoe crab spawning and knot densities at the refuge (Takahashi et al 2021). In our study area, knots appear to primarily feed on coquina clams on KSI itself, as horseshoe crabs do not currently occur on the islands, but horseshoe crabs do spawn on Deveaux Bank and knots are known to feed on their eggs there (Thibault & Levinsen 2013).…”

Section: Conservation Implicationsmentioning

confidence: 98%

Kiawah and Seabrook islands are a critical site for therufaRed Knot (Calidris canutus rufa)

Pelton

Padula

Garcia-Walther

et al. 2022

Preprint

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The rufa red knot (Calidris canutus rufa) is a migratory shorebird that performs one of the longest known trans-hemispheric migrations of any bird species - from their breeding grounds in the Canadian Arctic to their nonbreeding grounds as far south as Tierra del Fuego - and they have experienced a population decline of over 85% in recent decades. During migration, they rest and refuel at stopover sites along the Atlantic Coast, including Kiawah and Seabrook islands in South Carolina. Here, we document the importance of Kiawah and Seabrook islands for knots by providing population and stopover estimates during their spring migration. We conducted on-the-ground surveys between 19 February - 20 May 2021 to record the occurrence of individually marked knots. In addition, we quantified the ratio of marked to unmarked knots and deployed geolocators on knots captured in the area. Using a superpopulation model, we estimated a passage population of 17,247 knots (~41% of the total rufa knot population) and an average stopover duration of 47 days. Our geolocator results also showed that knots using Kiawah and Seabrook islands can bypass Delaware Bay and fly directly to the Canadian Arctic. Finally, our geolocators, combined with resighting data from across the Atlantic Flyway, indicate that a large network of more than 70 coastal sites mostly concentrated along the coasts of Florida, Georgia, South Carolina, and North Carolina provide stopover and overwintering habitat for the knots we observed on Kiawah and Seabrook islands. These findings corroborate that Kiawah and Seabrook islands should be recognized as critical sites in the knot network and, therefore, a conservation priority. As a result, the threats facing the sites - such as prey management issues, anthropogenic disturbance, and sea level rise - require immediate attention.

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Section: Conservation Implicationsmentioning

confidence: 98%

Kiawah and Seabrook islands are a critical site for therufaRed Knot (Calidris canutus rufa)

Pelton

Padula

Garcia-Walther

et al. 2022

Preprint

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show abstract

“…Subsequent work has revealed that shorebirds historically (Cramer, 2015) and currently exploit horseshoe crab eggs wherever horseshoe crabs spawn on the eastern seaboard (Smith et al, 2019;Takahashi, Sanders & Jodice, 2021), but there is no larger aggregation of spawning horseshoe crabs and shorebirds than the Delaware Bay coast of Delaware and New Jersey (Shuster & Botton, 1985).…”

Section: Introductionmentioning

confidence: 99%

“…Likewise, horseshoe crab eggs, larvae and early life stages are consumed by a wide variety of terrestrial and aquatic predators in the nearshore environment (DeSylva, Kalber & Shuster, 1962; Botton, 2009). Subsequent work has revealed that shorebirds historically (Cramer, 2015) and currently exploit horseshoe crab eggs wherever horseshoe crabs spawn on the eastern seaboard (Smith et al, 2019; Takahashi, Sanders & Jodice, 2021), but there is no larger aggregation of spawning horseshoe crabs and shorebirds than the Delaware Bay coast of Delaware and New Jersey (Shuster & Botton, 1985).…”

Section: Introductionmentioning

confidence: 99%

Horseshoe crab egg availability for shorebirds in Delaware Bay: Dramatic reduction after unregulated horseshoe crab harvest and limited recovery after 20 years of management

Smith¹,

Dey

Williams³

et al. 2022

Aquatic Conservation

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The largest aggregation of spawning American horseshoe crabs in the world occurs in Delaware Bay and supports one of the largest concentrations of shorebirds in the western hemisphere where the birds feed on horseshoe crab eggs during migration. Unregulated harvest in the 1990s is associated with the decline of shorebird populations using the bay, but corresponding baseline information on the horseshoe crab egg food supply that supported peak shorebird populations has been lacking. Past and current measurements of horseshoe crab eggs in the bay indicate that abundance in the 1980s was an order of magnitude greater (x̄ = 156,600/m2) than present‐day estimates (2015–2021 x̄ = 10,243/m2). An additional egg prevalence index, which characterizes the timing and magnitude of horseshoe crab egg output, revealed a similar pattern of higher prevalence in the 1980s (0.89, 95% confidence interval 0.81–0.94) compared with the recent 2015–2021 interval (0.52, 95% confidence interval 0.43–0.60). Declines of egg and shorebird abundance occurred shortly after horseshoe crab harvest reached its peak. Red knot aerial survey counts have stabilized at 30% of the baseline population while ruddy turnstone counts are 40% of baseline estimates. Initially these species were evenly distributed between the New Jersey and Delaware coasts but both species have trended toward predominately occupying New Jersey beaches. A lack of recovery of horseshoe crab egg and shorebird abundance suggests that horseshoe crab harvest management has stabilized populations but progress toward population recovery has been limited. Impacts from bycatch, the pharmaceutical industry and other potential population impacts must be better quantified and mitigated, if necessary, to promote the recovery of horseshoe crab populations. Measurements of horseshoe egg prevalence and abundance are essential metrics for tracking the progress toward management goals for improving shorebird habitat quality.

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Microplastic transfer from the American horseshoe crab to shorebirds through consumption of horseshoe crab eggs in Jamaica Bay, NY

Ward

Casper

Clark

et al. 2022

Marine Pollution Bulletin

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Spatial and temporal overlap between foraging shorebirds and spawning horseshoe crabs (Limulus polyphemus) in the Cape Romain-Santee Delta Region of the U.S. Atlantic coast

Abstract: BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Cited by 3 publications

References 35 publications

Kiawah and Seabrook islands are a critical site for therufaRed Knot (Calidris canutus rufa)

Kiawah and Seabrook islands are a critical site for therufaRed Knot (Calidris canutus rufa)

Horseshoe crab egg availability for shorebirds in Delaware Bay: Dramatic reduction after unregulated horseshoe crab harvest and limited recovery after 20 years of management

Microplastic transfer from the American horseshoe crab to shorebirds through consumption of horseshoe crab eggs in Jamaica Bay, NY

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