Virginia Institute of Marine Science
Journal of Shellfish Research
Single spat oysters Crassostrea virginica of four size classes (3.4-24.6 mm mean shell heights [SH]) were offered to six size classes of blue crabs Ca/linectes sapidus (9.3-85.5 mm mean carapace width [CW]) and five size classes of mud crabs Panopeus herbstii (7.1-34.4 mm mean CW) for 48 hr. Predation rate, recorded as the number of dead oyster spat/crab/day, was directly proportional to crab size and inversely proportional to oyster size. Mud crabs of 34.4 mm CW and blue crabs of 85 .5 mm CW had predation rates of 22.5 and 16.7 spat/crab/day on oyster spat of 24.6 and 24.4 mm SH, respectively. Larger sized spat could be more readily preyed upon by mud crabs than by blue crabs of similar size. Mud crabs of 7.1 and 25.2 mm CW caused significant mortalities to oyster spat of 8.1 and 24.6 mm SH, respectively. Blue crabs of 9.3, 24.5 and 85.5 mm CW caused significant mortalities to oyster spat of 3.4, 13.9 and 24.6 mm SH, respectively.
Predation, single spat oysters, Crassostrea virginica, crabs, Callinectes sapidus, Panopeus zerbstii
Bisker, Robert and Castagna, Michael, Predation On Single Spat Oysters Crassostrea Virginica (Gmelin) By Blue Crabs Callinectes sapidus Rathbun And Mud Crabs Panopeus herbstii Milne-Edwards (1987). Journal of Shellfish Research, 6(1), 37-40.