Mechanisms Determining Patterns in Fish and Crabs Associated with Development in Chesapeake Bay: Bottom-up Control

Natural coastal habitats throughout Chesapeake Bay are increasingly threatened with shoreline modification. Recently, patterns in fish and crabs have been associated with shoreline development, and the mechanisms behind these patterns are gaining interest.  In this study, we evaluated the effects of bulkhead, riprap, and natural marsh shorelines on benthic infauna and their predators, as well as the effects that sediment characteristics and wave exposure had on the response variables in several subestuaries in Chesapeake Bay. In AIC analyses, shoreline type emerged as the best predictor of infaunal diversity and was an important factor in determining density.  Sediment grain size and predator abundance also emerged as strong predictors of both density and biomass. Density of benthos was significantly affected by upland usage, and density increased with percent wetland in the subestuary.  Given that predator abundance and sediment type are strongly associated with benthic infauna and that these factors may also vary according to shoreline type and upland usage, the development of coastal systems will have complex results on subtidal benthic infauna. These effects will transfer up the food web to higher trophic levels (i.e., bottom-up control) linking land, water, benthic resources, and fisheries.