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Sea Squirt

Molgula manhattensis

The sea squirt has a rounded, leathery body and two short siphons. (Arjan Gittenberger)
The sea squirt has a rounded, leathery body and two short siphons. (Arjan Gittenberger)

The sea squirt is a tunicate with a rounded, leathery body and two short siphons. It lives on reefs, pilings and other hard surfaces in the shallow waters of the middle and lower Chesapeake Bay.

Appearance:

  • Round, leathery, yellowish- or greenish-brown body
  • Two short siphons projecting from the top of the body
  • Grows to a maximum of 2 inches

Habitat:

  • Lives in clumps on reefs, pilings, jetties and other hard surfaces in shallow waters

Range:

  • Found throughout the middle and lower Chesapeake Bay

Feeding:

  • Feeds by drawing water into the body through one of its siphons
  • Food particles are filtered through the pharynx and digestive tract
  • Waste products are ejected from the body through the other siphon

Reproduction and Life Cycle:

  • Spawns by releasing eggs and sperm into the water
  • After about three days, eggs develop into free-swimming, tadpole-like larvae. Larvae are fairly sophisticated: they have long tails, a primitive eye and backbone (called a notochord), a slender nerve cord, and a hollow, enlarged brain.
  • Larvae eventually settle and attach to a hard surface using an adhesive mechanism on the head
  • In about 3-4 days, the tail, nerve cord and notochord are absorbed, leaving only a small mass of nerve tissue. The body and siphons, as well as digestive, reproductive and circulatory organs, soon develop.

Other Facts:

  • Also called sea grapes because bunches of sea squirts look like bunches of grapes
  • When prodded, sea squirts will eject a jet of water from one of their siphons
  • Very tolerant of polluted water

Sources and Additional Information:


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