Whelks are several species of large, edible marine gastropods mollusks found in temperate, tropical waters around the world. They have hard shells built from calcium carbonate extracted from sea water. They are scavengers and carnivores as well as a popular food item for people throughout the world. While whelk is the name commonly used to refer to these sea snails, they are not all closely related.
The scientific name Buccinum undatum refers to the true whelk found in the Northern Atlantic waters near Europe. They can be found alive at low tide in the shallow waters of the British Isles, Belgium, and the Netherlands. The snail is approximately 4 inches (about 10 cm) in height and 2 inches (about 6 cm) wide, and it has a hard, pale-colored shell that is covered in a yellowish-brown thin skin known as the periostracum. Europeans claim that these large, edible snails taste best when boiled in sea water.
In the United States, the term whelk refers to another large, edible species known as Busycotypus, and it is much larger than those found in Europe. They can grow to 16 inches (about 40 cm) in height and have a solid cream, tan, or light gray shell. The snails are scavengers with large, muscular feet capable of boring through the shells of clams, crabs, and lobsters. Several species enjoy eating the Busycotypus, including sharks, seagulls, crabs, and humans.
The periwinkle is found along the rocky Scottish shorelines in the Northern Atlantic. The term periwinkle is interchangeable with what the people of Scotland refer to as whelks. This small gastropod with gills has a dark shell and feeds on algae or small invertebrates much like whelk found in other parts of the world. A popular food item with people worldwide, Scotland exports about 2,000 tons of periwinkles per year—it is considered an important export.
Another large variety of edible whelk not closely related to the species found in the United States or Europe is called the Cittarium pica. It lives on the shores of the West Indies and is a popular food item in the Caribbean, where it is also know as a wilk. These whelks are often boiled and eaten in numerous recipes on the islands. They are found living under rocks in shallow coastal waters of the Caribbean, Mexico, and other Latin American shores. The wilk has a large, black top shell with white stripes, is 5 inches (about 13 cm) in diameter, and feeds on algae.