bury one head sand

Knobbed whelk

The knobbed whelk, Busycon carica, is a species of very large predatory sea snail, or in the USA, a whelk, a marine gastropod mollusk in the family Melongenidae, the busycon whelks and crown conches.

The knobbed whelk is the second largest species of busycon whelk, ranging in size up to 12 in (305 mm).


Knobbed whelks are native to the North Atlantic coast of North America from Cape Cod, Massachusetts to northern Florida. This species is common along the Georgia coast. It is the state shell of New Jersey and Georgia.

Shell description

The shell of the knobbed whelk is dextral, meaning that it is right-handed. If you hold the shell in front of you, with the spiral end up and the opening facing you, the opening will be on the right side. The aperture of the shell (the inside of the opening) is orange.

External anatomy of the soft parts

The soft body comprises the head, the visceral mass, and the foot (which is small). The knobbed whelk has two pairs of tentacles on the head. The larger pair each have a light-sensitive eyespot. The smaller pair of tentacles is used for the sense of smell and the sense of touch.

Life habits

The knobbed whelk lives subtidally and is migratory, alternating between deep or shallow water, depending on the time of year.

During the weather extremes of the summer and winter months, these sea snails live in deep water, at depths of up to 48 m. In the milder weather of the spring and fall they live in shallow water, on near-shore or intertidal mud flats and sand flats.

On the shallow-water mud flats whelk prey on oysters, clams, and other marine bivalves. They wedge a bivalve open by inserting the edge of their shell, and insert their long proboscis to eat the flesh of their victim. They rasp at the flesh using their radula, a rough tongue-like organ that has thousands of tiny denticles (tooth-like protrusions).


Mating and egg laying occur during the spring and fall migration. Internally fertilized eggs are surrounded by a transparent mass of albumen, a gel-like material, and are laid in protective flat, rounded egg capsules joined to form a paper-like chain of egg cases, commonly called a "Mermaid's Necklace". On average each capsule contains 0-99 eggs, with most strings having 40-160 capsules. After laying their egg cases, female knobbed whelk will bury one end of the egg case into the substrate, thus providing an anchor for the developing fertilized eggs and preventing the string of egg cases from washing ashore where it would dehydrate. Fertilized eggs emerge as juvenile knobbed whelks approximately 4 mm in length.

Human use

As with conchs, the knobbed whelk is used by humans as food in such dishes as salads (raw), burgers, fritters, and chowders.

As is also true of conch shells, the shell of the knobbed whelk can be made into a natural bugle by cutting off the tip of the spire in order to form a mouthpiece.


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