Evaluating Relative Predator Impacts on Juvenile Blue Crab Mortality in Chesapeake Bay

The blue crab (Callinectes sapidus) population in Chesapeake Bay experienced a significant decline in 2012-2013 despite low exploitation rates and high juvenile abundance in early 2012. Conversely, alleged finfish predators of juvenile blue crabs experienced a population increase in 2012-2013, alluding to an increase in juvenile mortality by predation; however, there is minimal scientific evidence to support the speculation that these predators have the potential to significantly contribute to juvenile blue crab mortality and effectively reduce recruitment. Our primary objective was to investigate the influence of predators on the juvenile blue crab population in Chesapeake Bay. Gut content analysis and recorded tethering experiments were conducted to: (1) identify predators in seagrass beds; and (2) evaluate the relative impacts of these predators on juvenile mortality. Juvenile blue crab mortality was 91% per day overall, suggesting high rates of predation. Adult blue crabs were identified as a key predator of juveniles in seagrass beds, in addition to striped bass (Morone saxatilis), Atlantic croaker (Micropogonias undulatus), striped burrfish (Chilomycterus schoepfi), and northern puffers (Sphoeroides maculatus). Therefore, cannibalistic adult crabs and various finfish species have the potential to influence juvenile blue crab mortality in Chesapeake Bay seagrass beds.