Freshwater and Marine Ectoprocts or Bryozoans: Ectoprocta

Physical characteristics: Sea mats form star-shaped or wide sheets of calcified crusts on seaweeds, rocks, and shells. The zooids are longer than they are wide and are sometimes egg-shaped. They have four to twelve spines, giving the colony a "hairy" look.

Geographic range: They are found all around the world in oceans with waters that are not too cold or warm.

Habitat: Sea mats live in shallow marine waters down to approximately 164 feet (5 meters). Their colonies are attached to small species of marine algae (AL-jee) and on the shells of mussels and other mollusks.

Diet: They eat bits of algae floating in the water.

Behavior and reproduction: Very little is known about the behavior of sea mats.

Sea mats form star-shaped or wide sheets of calcified crusts on seaweeds, rocks, and shells. (Fred Bavendam/Peter Arnold, Inc.)

They reproduce asexually by budding. Sexual reproduction involves fertilized eggs released into the water where they hatch into larvae.

Sea mats and people: This species does not impact people or their activities.

Conservation status: Sea mats are not considered threatened or endangered. ∎