Primarily carnivorous scavengers, feeding on bivalves, worms and detritus. From Artic cold water shells to the southern oceans. Mostly oceanic but some genera are from fresh water. Many whelks are capable of boring through the shell of bivalves, and because of this some species cause much harm in oyster farms. True whelks can even attack fish caught in a net extending their proboscis to twice the length of their own bodies.