A conch (pronounced in the U.S.A. as "konk" or "konch", or /ˈkɒntʃ/) is one of a number of different species of medium-sized to large saltwater snails or their shells. True conchs are marine gastropod mollusks in the family Strombidae, and the genus Strombus.
The name "conch" however, is often quite loosely applied in English-speaking countries to several kinds of very large sea snail shells which are pointed at both ends, i.e. shells which have a high spire and a noticeable siphonal canal. These other species include the crown conch Melongena species; the horse conch Pleuroploca gigantea; and the chank shell, Turbinella species. None of these are true conchs; they are all in other taxonomic families.
The true conch species within the genus Strombus vary in size from fairly small to very large. Several of the larger species such as Strombus gigas, the pink conch or queen conch, are economically important as food sources. Strombus gigas is also capable of producing (very rarely) a pink, gem quality pearl.
At least 65 species of Strombidae are extinct, and a much larger number of species exist only in the fossil record. Of the living species, most are in the Indo-Pacific Oceans. Six species live in the greater Caribbean region, including the Queen Conch, Strombus gigas, and the West Indian Fighting Conch, Strombus pugilis.
Many species of conch, such as the Queen Conch, live on sandy bottoms among beds of sea grass in warm tropical waters.
Like almost all shelled gastropods, conches have spirally constructed shells. Again, as is normally the case in many gastropods, this spiral shell growth is usually right-handed, but on very rare occasions it can be left-handed.
True conchs have long eye stalks, with colorful ring-marked eyes. The shell has a long and narrow aperture, and a short siphonal canal, with another indentation near the anterior end called a stromboid notch. This notch is where one of the two eye stalks protrudes from the shell.
The true conch has a foot ending in a pointed, sickle-shaped, operculum which can be dug into the substrate as part of an unusual "leaping" locomotion.
True conchs grow a flared lip on their shells only upon reaching sexual maturity. Animals which are harvested by fishermen before they reach this stage are juveniles, and have not had a chance to reproduce.
Conchs lay eggs in long, gelatinous strands.
In El Salvador, live conch is served in a cocktail of onion, tomato, cilantro, and lemon juice. Lemon juice is squeezed onto the cocktail, causing the conch to squirm, and then the whole thing is slurped down whole, as in the manner of oysters.
Conch meat is also often confused with what in the US is known as "Scungilli", which is more accurately whelk meats.
Conch shell trumpets were historically used throughout the South Pacific, in countries such as Fiji. In resorts in Fiji they still blow the shell as a performance for the tourists. The Fijians also used the conch shell when the chief died: the chief's body would be brought down a special path and the conch would be played until the chief's body reached the end of the path. Only the chief's body could go down that path.
The American jazz trombonist Steve Turre also plays conches, notably with his group Sanctified Shells.
A partially echoplexed Indian conch was featured prominently as the primary instrument depicting the extraterrestrial environment of the derelict spaceship in Jerry Goldsmith's score for the film Alien. Director Ridley Scott was so impressed by the eerie effect that he requested its use throughout the rest of the score, including the Main Title.
Composer John Cage has used partially water-filled conch shells, which, when tilted slowly, create gurgling sounds beyond the player's control, which are then amplified. This sound effect was used by James Horner in the film Troy and by Annea Lockwood in her compositions.
In the story of Dhruva the divine conch plays a special part. The warriors of ancient India blew conch shells to announce battle, as is described in the beginning of the war of Kurukshetra, in the Mahabharata, the famous Hindu epic.
The god of Preservation, Vishnu, is said to hold a special conch, Panchajanya, that represents life, as it has come out of life-giving waters.
The famous Old English riddle Ic wæs be Sonde describes a conch: "I was by sound, near seawall, at ocean-stream; I dwelt alone in my first resting place. ... Little did I know that I, ere or since, ever should speak mouthless over mead-benches."
In popular folklore, it is believed that if one holds an open conch shell (or any other large marine snail shell) to the ear, the ocean can be heard. This phenomenon is caused by the resonant cavity of the shell producing a form of pink noise from the surrounding background ambiance. In reality, the person is hearing their blood flow in the capillaries of their ears; the sound enters the shell and reverberates through the chambers before coming back. This sound can also be heard (though rather poorly) by covering one's ear with one's hand. The rushing sound is the flow of blood.