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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:

The sea squirt has a round, leathery, yellowish- or greenish-brown body with two short siphons projecting from the top. It grows to a maximum of two inches in length.

Habitat:

Live in clumps on reefs, pilings, jetties and other hard surfaces in shallow waters.

Range:

Found throughout the middle and lower Chesapeake Bay.

Feeding:

The sea squirt feeds by drawing water into the body through one of its siphons. Food particles are filtered through the pharynx and digestive tract, and waste products are ejected from the body through the other siphon.

Reproduction and Life Cycle:

The sea squirt 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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