Influences of an urban estuary on blue crabs and blue crab diet

Meredith Nishiura

Mentor: Dr. Eric Schott

Institute of Marine and Environmental Technology

Increasing development and urbanization are widespread and critical issues facing marine estuaries, which are productive ecosystems that are crucial both ecologically and economically. The blue crab Callinectes sapidus, which functions as a prevalent predator and prey species, is one of the most important organisms in the Chesapeake Bay. The effects of life in urban estuaries on blue crabs have gone underexplored in the past, particularly their role in the food web dynamics of these urban areas. Comparing data on blue crab diet to existing data on the prey community of the area can allow for a complete 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. Organisms were counted from the disks, and these counts were converted to approximate biomass using a model of each organism’s average mass. The resulting biomass better represents the prey available to blue crabs, with barnacles, dark false mussels, oyster flatworms and clam worms making up the majority of the biomass and thus being the most likely prey species. Future work will utilize the emerging technique of DNA metabarcoding to identify the species composition in the stomachs of blue crabs from the Baltimore Inner Harbor. The data may inform future research into the ecosystem dynamics of urban areas and provide insight into these precarious yet increasingly common communities.