Whelks are marine gastropods that inhabit oceans worldwide. These creatures, often recognized by their distinctive spiral shells, have captivated both scientists and enthusiasts for their unique characteristics and ecological roles. Exploring the world of whelks reveals their diverse forms, their place in marine ecosystems, and their interactions with human societies.
Defining Whelks
Whelks belong to the class Gastropoda within the phylum Mollusca. The family Buccinidae is commonly referred to as “true whelks,” though the term “whelk” can also apply to species in other families like Melongenidae and Busyconidae. There are over 1,500 known species of whelks globally, varying significantly in size and appearance. Their shells typically exhibit a spiral shape, ranging from less than an inch to over two feet in length, such as the trumpet whelk.
A whelk’s shell often features an aperture, the opening from which the soft-bodied animal extends. Attached to its muscular foot is a hard plate called an operculum, functioning as a protective door that seals the shell when the snail retracts. Whelks also possess a siphon, a tube-like organ that draws in oxygenated water, enabling them to breathe even when partially buried in sediment. On their head, whelks have tentacles for sensing their environment and a proboscis, a tube-like feeding organ with a radula, a rasping structure used for feeding.
Whelks are found in diverse marine environments, from the intertidal zone to depths of 1,200 meters or more, inhabiting temperate, tropical, and polar regions. They can be found on various substrates, including muddy sand, gravel, and rock, and some species can burrow into softer sediments. The common northern whelk (Buccinum undatum), for instance, is abundant in North Atlantic waters, including British coasts, and can live down to 1,200 meters.
Whelks in Their Environment
Whelks are carnivorous predators and active scavengers. Their diet consists of other mollusks, such as clams, oysters, and mussels, as well as crustaceans and marine worms. Whelks use chemosensors to detect food in the water, extending their siphon to funnel water over a sensory organ.
To access prey, whelks employ various feeding strategies. Some species use their radula to bore a hole into the shells of bivalves, injecting digestive enzymes to soften the tissue before consuming it. Other whelks may use the lip of their own shell and their strong muscular foot to chip away at a clam’s shell, prying open the valves to insert their proboscis and feed. Whelks are preyed upon by various marine animals, including crabs, sea stars, sea turtles, urchins, and fish such as cod.
Whelks and People
Whelks have a significant relationship with humans as a food source in many cultures around the world. The muscular foot of the whelk is commonly consumed, with an example being the Italian dish “scungilli.” These marine snails are prepared in various culinary traditions and are valued for their meat.
Commercial fisheries target whelks, recognizing their economic importance. In 2020, the whelk fishery was valued at £19.8 million in England, making it the fourth most valuable fishery in the region. Whelks are caught using baited pots, which are weighted containers placed on the seafloor to attract the snails, then hauled up every one to three days. Whelks can also be caught as bycatch in other fishing gear, such as lobster traps.
Beyond food, whelks are collected for their shells in the seashell trade, and their egg cases have historically been used as a type of “fishermen’s soap.” Some whelk species, like the knobbed whelk, hold cultural significance, serving as state shells for regions such as New Jersey and Georgia.