Sea squirts are tunicates, marine filter feeders that collect food by pulling water through an incurrent and excurrent siphon. There are many difference types, with different life histories, but most are fouling organisms that can be introduced by boats.
Tunicates are distant relatives of vertebrates; their tadpole larvae have a notochord, the precursor of a backbone. They also have muscles arranged along their sides similar to fish. Adult Rough Sea Squirts are 3 cm long and egg-shaped with a smooth reddish-brown outer layer.
They are so widely distributed across temperate and tropical coastal waters that their native region is unknown. They were described from the Red Sea in but are found on both sides of the North Atlantic, the northwest Pacific, the tropical Indo-Pacific, and Australia.
They were seen for the first time in the Chesapeake Region in when two specimens were found at Cape Charles VA; other specimens have since been collected in the lower Bay. Styela canopus Rough Sea Squirt is now widely distributed in temperate and tropical coastal waters of the world. It was described from the Red Sea in , and was later found on both sides of the North Atlantic, Ascension Island in the South Atlantic, the northwest Pacific, the tropical Indo-Pacfic, and temperate waters of Australia.
Kott In the Atlantic, it was first reported as Cynthia partita from Boston Harbor in Stimpson and then from the English Channel as Styela variabilis in , and from the Mediterranean as S. In the northwest Pacific, where it is a recent introduction, S. James Carlton considers Styela canopus to be a native of the Indo-West Pacific Carlton personal communication , introduced to the Atlantic possibly a century or more before its description , a judgment which we have adopted here.
