gribble

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gribble

crustacean

Also known as: Limnoria

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Related Topics:: Limnoria tripunctata; Limnoria saseboensis; Limnoria pfefferi; Limnoria lignorum

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gribble, any of the approximately 20 species of wood-boring, marine crustaceans constituting the genus Limnoria, in the order Isopoda. They feed on algae, driftwood, and the submerged wood of docks and wharves and sometimes attack the nonwoody insulation of submarine cables.

Limnoria lignorum, which occurs throughout the seas of the Northern Hemisphere, grows to 5 mm (0.2 inch) in length and has a gray body consisting of 14 clearly defined segments. It burrows about 12 mm into wood. L. tripunctata occurs in the Atlantic Ocean from New England (U.S.) to Venezuela and in the Pacific Ocean from California to Mexico. It even penetrates wood that has been impregnated with creosote, an offensive chemical that repels most wood-boring invertebrates. L. pfefferi is found in the Pacific and Indian oceans; L. saseboensis is found on the Atlantic coast of the southeastern United States and on the coast of Japan.

This article was most recently revised and updated by Amy Tikkanen.

shipworm

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shipworm

mollusk

Also known as: Teredidae, Teredinidae, pileworm

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Also called:: pileworm

Related Topics:: Bankia; common shipworm; wood borer; Myoida; Teredo

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shipworm, any of the approximately 65 species of marine bivalve mollusks of the family Teredidae (Teredinidae). Shipworms are common in most oceans and seas and are important because of the destruction they cause in wooden ship hulls, wharves, and other submerged wooden structures.

Only a small part of the anterior end of the shipworm is covered by a shell; the remainder is a long tubelike structure that, in some species, may be 180 cm (6 feet) long. The white shell, often marked with closely set lines, is used for burrowing into wood. File-like ridges on the shell cut into the wood at a rate of about 8 to 12 rasping motions a minute. Shipworms secrete lime to line the inside of the burrow. The tubelike portion of the animal, which extends back to the burrow opening, ingests food particles and oxygen from the water and discharges wastes and reproductive cells. A certain amount of wood is also ingested as food by most species.

The most economically important shipworms, i.e., those causing the most damage, are members of the genus Teredo, which includes about 15 species. Other genera are Bankia, Xylotrya, and Xylophaga. Teredo norvegica, of the coasts of Europe, has a tube about 30 cm (1 foot) long. The common shipworm, T. navalis (20 to 45 cm [8 to 18 inches] long), has a worldwide distribution but is especially destructive on the Baltic Sea coast.

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This article was most recently revised and updated by Amy Tikkanen.