The Potential of the Bull Chub (Nocomis raneyi) as a Predator of the Zebra Mussel (Dreissena polymorpha) in Mid-Atlantic Coastal Rivers

-The feeding ecology and pharyngeal teeth of the bull chub (Nocomis raneyi) were investigated to determine whether the species could potentially crush and ingest zebra mussels (Dreissena polymorpha), should this mollusk become established in coastal rivers of the mid-Atlantic United States. We hypothesized that if bull chubs could crush mollusks similar in size and shell thickness to zebra mussels, bull chubs could successfully prey upon zebra mussels. The introduced Asiatic clam (Corbicula fiuminea) was used as a surrogate for the zebra mussel. Gut content analysis of larger (TL = 126 mm+) bull chubs from the James River, Virginia, revealed that mollusks were a dominant prey item, and Asiatic clams were ingested by bull chubs >125 mm TL. Shell thicknesses of zebra mussels and Asiatic clams of equivalent shell lengths were compared, and Asiatic clam shells were significantly thicker (P < 0.001) than zebra mussel shells. Because bull chubs ingest and crush the thicker-shelled Asiatic clam, the fish could successfully prey upon the zebra mussel if it becomes established in coastal rivers of the mid-Atlantic United States.