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Gould’s Shipworm

Bankia gouldi

Shipworm tunnels are often seen in pieces of driftwood that wash ashore. (alaskanent/Flickr)
Shipworm tunnels are often seen in pieces of driftwood that wash ashore. (alaskanent/Flickr)

Gould’s shipworm is a bivalve with a long, worm-like body. It lives within untreated wood, such as pilings and driftwood, in the middle and lower Chesapeake Bay.

Appearance:

  • Long, worm-like body
  • Two small shells with toothed ridges at one end of the body
  • Two small siphons and two hard, segmented pallets at the other end of the body. The pallets look like stacks of tiny ice cream cones.
  • Grows several inches long

Habitat:

  • Lives within calcified tunnels in untreated wood. The tunnels protect the shipworm’s soft body.
  • Uses its boring shells to scrape away pieces of wood to form a tunnel
  • The end of each tunnel has a pinhole-sized entryway to the water. The shipworm’s siphons stick out into the water through this hole.
  • Each shipworm’s tunnel never intersects with another tunnel, even if there are multiple tunnels in a single piece of wood

Range:

  • Found throughout the lower Chesapeake Bay
  • Ranges into the brackish waters of the middle Bay

Feeding:

  • Feeds mainly on wood
  • May also eat planktonic particles brought in through the incurrent siphon

Reproduction and Life Cycle:

  • Releases eggs into the water column. Free-swimming larvae eventually hatch from the eggs.
  • Larvae remain in the water for 2-3 weeks before settling on any submerged untreated wood surface, such as pilings, ship planking, and tree trunks or branches
  • Larvae use a small foot to move around on the wood’s surface. Once they find a suitable place, they anchor themselves using thin threads secreted from a gland on the foot.
  • Larvae use their tiny boring shells to drill and burrow into the wood, where they develop into adults

Other Facts:

  • Although they look like worms, shipworms are actually mollusks. They are closely related to boring clams.
  • As early as 412 B.C., mariners tried to protect their ships’ hulls from shipworms using chemicals such as sulphur and arsenic
  • White shipworm tunnels are often seen in pieces of driftwood that wash ashore. The tunnels are about the width of a pencil and follow the wood’s grain.

Sources and Additional Information:




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