Effects of an Urban Estuary on Blue Crabs and Blue Crab Diet

Overview

Increasing development and urbanization greatly affect ecosystem dynamics in marine estuaries, yet these effects have gone underexplored. The blue crab Callinectes sapidus is a keystone species in the Chesapeake Bay, an estuary facing increased urbanization. Comparing data on blue crab diet to existing data on the prey community of the urbanized area can allow for a comprehensive picture of the interaction between blue crabs and the larger ecosystem. Data on the biodiversity of the Baltimore Inner Harbor were previously collected from biodisks, small disks placed in the harbor and allowed to accumulate a community of organisms. The resulting biomass represents the prey available to blue crabs, with barnacles, dark false mussels, oyster flatworms and clam worms composing the majority of biomass. DNA metabarcoding was used to compare these results to the stomach contents of blue crabs caught in the harbor, which resulted in an overamplification of blue crab DNA and underrepresentation of prey species, demonstrating the need for a blocking primer to suppress predator DNA. Future work will utilize a designed blocking primer to amplify prey species. The data may inform future research into the ecosystem dynamics of urban areas and provide insight into these marginal yet increasingly common communities.