Channeled Whelk

(Busycotypus canaliculatus)

Overview

Channeled whelks are a type of marine snail found from the coastal waters of Massachusetts southward through Florida. After the animals die, their pear-shaped shells occasionally wash up and can be easily identified by the deep groove or channel running between the whorls atop the shell's spire.

Like their close relatives the knobbed whelks, these snails rely on their shells for protection. The shell grows with the snail, as the animal secretes minerals and proteins that harden in layers. When threatened, the snail retreats inside; the operculum, a hard shield attached to the snail's muscular foot, acts as a stopper or door at the shell opening.

Channeled whelks themselves are soft-bodied. When they are active, you can see the head and foot emerging from within the shell. Their heads have two narrow tentacles near the front, where eye spots are located, and a proboscis that they can retract. The proboscis is a tube-like structure with rasping teeth used for eating hard-shelled prey. Whelks move using their foot, which produces a slimy mucus that helps them glide along the sand.

Quick Facts

Learn more about channeled whelks! Did you know channeled whelks, along with all their snail, slug and limpet relatives, undergo torsion early in their lives? Torsion is when part of their body permanently twists 180 degrees within the shell. This allows the animal to pull its head into its shell before its foot, better protecting it.

Channeled whelks, like knobbed whelks, are found along the North Atlantic coast from Massachusetts to Florida.

A small channeled whelk population has established itself in San Francisco Bay, California, having been introduced there sometime in the 20th century. The Bay's temperature is warm enough, but the water outside is too cold for the snails to tolerate. This, coupled with the species developing within eggs rather than having a free-swimming larval phase, keeps the population from spreading.

Channeled whelks are predatory, preferring to eat bivalves like oysters and mussels. They will wedge the lip of their shell in between a bivalve's two shells to pry them open. Channeled whelks are also known to scavenge for food; fisheries often use pieces of horseshoe crabs as bait to lure the whelks into pots and bags.

Channeled whelks hatch from egg cases as miniature versions of their adult forms, usually with shell lengths of less than a tenth of an inch. Adults reach 5 to 8 inches, sometimes growing even larger. Whelks grow slowly and typically increase in size in short bursts rather than gradually. Often, they can go multiple seasons or years without getting bigger.

Few studies of the channeled whelk population exist. Despite being an important fishery along the eastern seaboard, individual states placed different limits on the size and number of channeled whelks that could be caught each year. Some areas report that channeled whelks are overfished, while others have not seen the same drop in numbers.

Young channeled whelks are eaten by a variety of crabs. As adults, they are preyed upon by large crabs and sea turtles.

The channeled whelk is sought after by people, too. Whelk fisheries in the U.S. have existed since the mid-20th century, as whelk meat is used in dishes from fritters to salads.

Meet the Expert Jay Bradley

As curator of Blue Wonders: Reefs to Rainforests, Jay Bradley oversees the care of all animals in Blacktip Reef, Living Seashore, Shark Alley and more.

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