Image ID 417003 Premium Services    Common Shipworm (Teredo navalis) (left - hand figure) and other marine invertebrates Hand-colored lithograph after "Mr. Sowerby" (probably George Brettingham Sowerby) From: John George Wood, The Common Objects of the Seashore: including hints for an aquarium (London, 1866) NYPL, General Research Division

Teredo navalis (left - hand figure), although wormlike in shape, is actually a wood-boring bivalve mollusk related to clams. One of the few animals that can actually digest cellulose, the shipworm destroys wood pilings and boats by riddling them with tunnels. Its depredations go back through history: in 1503, on his fourth voyage to the New World, Christopher Columbus lost two of his four ships to borers.

Ironically, these invasive marine pests were not a problem when local waters were heavily polluted. As the harbor and rivers gradually became cleaner under the impetus of the 1972 Federal Clean Water Act, many previously vanished species returned. Unfortunately, Teredo and another borer, the crustacean Limnoria lignorum, or Gribble, were among them. Various waterfront construction technologies, all costly, have been employed to shore up weakened structures and prevent new
destruction: the Sanitation Department spent more than $5.5 million in 1998 to combat borer damages at its waterside plants.