Species Information

Star tunicate (Botryllus schlosseri) Star tunicate (Botryllus schlosseri)
A. Pappal
Star tunicate (Botryllus schlosseri)
A. Pappal
Star tunicate
Botryllus schlosseri

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  • Individual animals (zooids) live in colonies up to 3-4 in (7.5-10 cm) wide
  • Zooids arranged in conspicuous starlike patterns
  • Yellow, olive, greenish, tan, brown, purple, or black; individuals outlined in yellow or white
  • Colonies begin as soft, flat patches and mature into loose bloblike rolls and lobes

  • Grows on rocks, shells, seaweeds, pilings, eelgrass, and other solid surfaces
  • Along open shores and in brackish estuaries (to 18 ppt or less)
  • Near low-tide line and below, to depths of 60 ft (18 m)

Known Distribution in the Northeast
  • Newfoundland to Florida
  • Native to Europe

  • Competition with native species (invertebrates and algae) for living space
  • Often grows on mussels and oysters, interfering with their feeding and other behaviors food and resources

Star tunicate (Botryllus schlosseri)
MIT Sea Grant College Program
Star tunicate (Botryllus schlosseri)
N. Balcom, CT Sea Grant

Protecting the marine and freshwater resources of the Northeast from invasive aquatic nuisance species