Meeting Abstract

P3.27  Thursday, Jan. 6  Bottom-up Control in the Patuxent River, Maryland: Impacts of Shoreline Hardening on Infaunal Communities, Crabs, and Fish BRADLEY, Cassie*; SEITZ, Rochelle; VIMS, College of William and Mary cbradley@vims.edu

Worldwide, natural coastal habitats are increasingly threatened with anthropogenic modification. Of particular concern in Chesapeake Bay are the effects of shoreline development, specifically the replacement of the natural coastline with hardened structures. In this study, we investigated the local impacts of shoreline development in the Patuxent River, MD, with respect to both infaunal communities and their predators. Three shoreline types, natural salt marsh (Spartina alterniflora), riprap, and bulkhead, were examined. Predator abundance was highest adjacent to natural marsh and lowest adjacent to bulkhead and was dominated by three species: blue crab (Callinectes sapidus), white perch (Morone americanus), and spot (Leiostomus xanthurus). Further, results from an AIC analysis revealed predator abundance to be a strong predictor of infaunal density and biomass, with lowest infaunal density and highest infaunal biomass occurring in conjunction with higher predator abundances. The positive correlation between infaunal biomass and predator abundance suggests the influence of bottom-up control in this system, as predators pursue suitable prey items. Thus, the replacement of natural shorelines with hard structures may affect ecologically important benthic crustaceans and fishes not only by altering nearshore habitat suitability, but also through direct impacts to adjacent infaunal food sources.