Food
Blue crabs are classified as general scavengers, bottom carnivores (eats other animals), detritivores (eats decaying organic matter), and omnivores (eats either other animals or plants). At various stages in the life cycle, blue crabs serve as both prey and as consumers of plankton, benthic macroinvertebrates, fish, plants, mollusks, crustaceans (including other blue crabs), and organic debris. Food is located by a combination of chemoreception (chemical sense) and taction (touch). Blue crabs may play a significant role in the control of benthic populations.
Macroinvertebrates are organisms without backbones (e.g., insect larvae, annelids (leeches), oligochaetes (worms), crustaceans (crabs, crayfish and shrimp), mollusks (clams, oysters and mussels), and gastropods (snails)) and inhabit bottom substrates (e.g., sediments, debris, logs, macrophytes, and filamentous algae.)
Adult Food
Adult blue crabs prefer mollusks such as oysters and hard clams as their primary food sources. The crab uses the tips of its front-most walking legs to probe the bottom for buried bivalves and to manipulate them after they are located. Some other common food items include dead and live fish, crabs (including other blue crabs), shrimp, benthic macroinvertebrates, organic debris, and aquatic plants and associated fauna such as roots, shoots and leaves of sea lettuce, eelgrass, ditch grass, and salt marsh grass. It will also prey on oyster spat, newly set oysters and clams, or young oysters and quahogs if other food is unavailable.
Juvenile Food
Juvenile blue crabs feed mostly on benthic macroinvertebrates, small fish, dead organisms, aquatic vegetation and associated fauna.
Larval Food
Zoeae are phytoplanktivorous and readily consume algae, phytoplankton and zooplankton. Megalope are considered general scavengers, bottom carnivores, detritivores, and omnivores. Megalope are more omnivorous than zoeae and prey upon fish larvae, small shellfish, and aquatic plants.