Sea Squirts: Ascidiacea

Physical characteristics: Botryllus schlosseri sea squirts live in flat colonies on rocks or algae. The colonies reach a width of about 4 inches (10 centimeters). Systems of individual sea squirts are embedded in a soft, slimy dark brown sheet in circular patterns that look like daisies. The system's common opening looks like the center of the flower. The individual sea squirts have a white or yellow stripe on top.

Geographic range: Botryllus schlosseri (abbreviated to B. schlosseri) sea squirts live on both sides of the Atlantic Ocean.

Habitat: B. schlosseri sea squirts live in shallow water on rocks, shells, and algae.

Diet: B. schlosseri sea squirts eat nutrient particles they strain from the water flowing through them.

Botryllus schlosseri eat nutrient particles they strain from the water flowing through them. (Illustration by Emily Damstra. Reproduced by permission.)

Behavior and reproduction: B. schlosseri sea squirts attach themselves to the surface on which they live. Fertilization and the development of larvae take place within the colony.

Botryllus schlosseri and people: B. schlosseri sea squirts have no known importance to people.

Conservation status: B. schlosseri sea squirts are not considered threatened or endangered. ∎