Knobbed Whelk (Busycon carica)
The empty shell of a knobbed whelk (Busycon carica) is sometimes used by oyster larva (free-swimming young) as hard substrate to permanently settle on. (Photo courtesy of Sara K. Saksewski)
The knobbed whelk, named for the knob-like projections on the upper, spiral part of its shell, is common in South Carolina estuaries (where rivers meet the sea). This snail lives on sandy and muddy bottoms in waters as deep as 60 feet. It moves through the sand and mud using a muscular foot. The knobbed whelk feeds mainly on bivalves, such as oysters and clams. The knobbed whelk can be harvested commercially or recreationally in South Carolina (albeit with restrictions).