An Evaluation of Mississippi Barrier Islands as a Spawning and Nesting Habitat for the American Horseshoe Crab, Limulus polyphemus, with Implications for Island Restoration

Abstract

The American horseshoe crab (HSC), Limulus polyphemus, is an economically and ecologically important species in the coastal ecosystem. Horseshoe crabs inhabit the continental shelf and estuaries from Maine to the central Gulf Coast and the Yucatán Peninsula. Although the presence of horseshoe crabs in southern Mississippi is known locally, there are limited data specific to the area and population, particularly regarding spawning and nesting habitat. Surveys of HSC presence, habitat use, and behavior on Mississippi barrier islands were conducted between March and November 2007 to 2009. These data, combined with habitat surveys of the barrier islands, were used to characterize HSC use of these islands. Horseshoe crabs were present on barrier island beaches from March to November, but active spawning and nesting occurred primarily in April and May. Peak abundance varied by year but not between islands surveyed. Nesting activity was only observed on the north side of both islands and was generally clustered in areas with a mild elevation profile. In comparison to other studied populations both in the Gulf of Mexico (GOM) and along the U.S. Atlantic coast, HSC nesting on Mississippi barrier islands followed generally similar patterns, but did display some important differences. Nesting was highest in low energy, well oxygenated habitat, which included the sub-tidal sand flats that are common along these islands. In addition, HSC are smaller than the range-wide mean reported in the literature, but that may be related to these islands being close to the edge of the reported HSC range in the GOM. The continued existence of HSC in Mississippi appears tied to their preference for barrier island beaches as spawning and nursery habitat. More research is needed, but this study documents that the distribution of HSC nesting habitat includes Mississippi beaches and this should be considered as a part of restoration plans being evaluated for these barrier islands.

Conservation status of the American horseshoe crab, (Limulus polyphemus): a regional assessment

“…However, horseshoe crabs are regularly seen breeding on the northern side of the Alabama barrier islands, on the Fort Morgan Peninsula and in the Gulf Shores area (Estes 2015), and west of Mobile Bay at Dauphin Island, Alabama (Hedgpeth 1954;Richmond 1962;Ruth Carmichael, Dauphin Island Sea Lab, personal communication), with breeding pairs rarely observed on the Fort Morgan Peninsula and Gulf Shores area of Alabama (Estes 2015), and occasional solitary individuals are found on the southern side of the barrier islands in Alabama and Mississippi (Ruth Carmichael, Dauphin Island Sea Lab, personal communication). Horseshoe crabs also breed on Mississippi's Petit Bois Island (Ruth Carmichael, Dauphin Island Sea Lab, personal communication; Estes et al 2015), Horn Island (Steve J. VanderKooy, Gulf States Marine Fisheries Commission, personal communication) and West Ship Island (Fulford and Haehn 2012). The western extent of historically recorded horseshoe crab breeding in the Gulf of México is the Chandeleur Islands, the easternmost barrier islands of Louisiana (Cary 1906).…”

“…In Georgia and South Carolina, spawning has been reported from March to July, peaking in May (Thompson 1998 (Rudloe 1980;Brockmann et al 2015; FWC online survey). In Mississippi, spawning is observed from early April to mid-November with a peak in April and May (Fulford and Haehn 2012). In the Yucatán spawning activity is associated with decreased water temperatures (unpublished data, J. Gutiérrez and J. Zaldívar-Rae, Anáhuac Mayab University), and they seem to spawn throughout the year (Á lvarez-Añorve et al 1989;Barba-Macias et al 1988;Bonilla-González et al 1986;Rosales-Raya 1999).…”

“…Spawning is sometimes observed on offshore sandbars and oyster bars (Wenner and Thompson 2000). On the Mississippi coastal islands, breeding occurs primarily on the protected north sides of intertidal sand beach habitat (Fulford and Haehn 2012). Some sub-tidal nesting also occurs in sands with high oxygen, such as the sand flats just off the beach.…”

Environmental factors and occurrence of horseshoe crabs in the northcentral Gulf of Mexico

“…Previous research in the northcentral GOM indicates sparse presence of L . polyphemus among the sandy beaches on the lee shore of the barrier island system that extends from Louisiana to the Fort Morgan peninsula in Alabama [ 2 , 4 ]. L .…”

Nursery habitat for Asian horseshoe crabs along the northern Beibu Gulf, China: Implications for conservation management under baseline gaps

“…Horseshoe crabs use a wide variety of habitats throughout their life cycle: adults nest on wave-protected beaches near the high tide mark, the larvae emerge from sediment and enter the sea as plankton following wave action, the larvae settle onto the same or adjacent intertidal flats and grow into juveniles, and adults forage in subtidal areas <30 m deep (Botton, Loveland, & Tiwari, 2003;Chen et al, 2015;Smith et al, 2017). American horseshoe crabs have demonstrated to be selective in their choice of spawning and nursery habitats (Fulford & Haehn, 2012;Medina & Tankersley, 2010). For Asian horseshoe crabs, a great deal of attention has been devoted to documenting declining juvenile recruitments Lee & Morton, 2016;Liao, Hsieh, et al, 2019;Weng et al, 2012).…”