Studies of the Distribution and Feeding Habits of Some Oyster Predators in Alligator Harbor, Florida

Observations were made on the distribution in Alligator Harbor and ability to kill oysters of Busycon contrarium Conrad, Melongena corona Gmelin, Murex pomum Gmelin, Thais haemastoma Conrad, Pleuroploca gigantea Keiner, Menippe mercenaria Say and Callinectes sapidus Rathbun. B. contrarium were numerous and very destructive to oysters, killing them mainly by chipping the edges of the shell, also by forcing the oyster's valves apart. M. corona feed by inserting the proboscis in the relaxed and open oyster. They were sometimes locally abundant but were not established as a serious oyster predator. M. pomum were abundant, but only subtidally below the intertidal oyster reefs, and killed available oysters by drilling the shell. T. haemastoma were very scarce and of no importance as an oyster enemy in the area. P. gigantea, sporadic in occurrence, did not feed on oysters. M. mercenaria and other xanthid crabs were very abundant and destroyed many oysters by breaking the shells. C. sapidus were abundant. They kill healthy small oysters, but only weakened large oysters.