shipworm

Shipworm is the common name for a group of wood-boring marine bivalve mollusks in the family Teredinidae. Despite the name, they are not true worms; their worm-like bodies and wood-boring habit earned the label. They bore into submerged wood such as ship hulls, docks, pilings, and wrecks, often weakening wooden structures over time.

Anatomy and biology: Shipworms have elongated, soft bodies with two calcareous shells at the anterior end and long siphons used for feeding and respiration. They live inside a burrow they carve in wood and extend their bodies through the tunnel. A key adaptation is a symbiotic relationship with bacteria housed in their gills, which digest cellulose from wood, enabling the mollusks to extract nutrients from timber.

Distribution and habitat: They are found in coastal and estuarine waters worldwide, particularly in warm to temperate regions, and can tolerate brackish conditions where submerged wood is available. They commonly colonize ship timbers, piers, pilings, and submerged wrecks.

Life cycle and impact: Reproduction is sexual, with free-swimming larvae that settle on suitable wood and metamorphose into adults. Their boring activity can compromise wooden structures, making them an ongoing concern for older ships, historic wrecks, and underwater infrastructure. Control measures historically included copper sheathing and anti-biofouling coatings.

Significant species include Teredo navalis (the common shipworm), as well as other teredinids in the genera Lyrodus and Bankia. They exemplify marine wood-borers that rely on symbiotic digestion to exploit timber in the sea.