Ciona robusta

Ciona robusta is a marine invertebrate characterized by its translucent tunic and off-white body, often adorned with orange to red dots along the scalloped edges of its siphons. This species can be distinguished from similar tunicates such as Ciona savignyi by the absence of white pigmented flecks and its more robust tunic. The body is elongated and vase-shaped, typically reaching a size of up to 210 mm, though it usually does not exceed 100–120 mm. The siphons are short and directed forward, with the oral siphon being larger than the atrial siphon. Ciona robusta is primarily found in subtidal zones but can occasionally inhabit low intertidal areas, preferring salinities of 11 to 50 ppt. It has been recorded at depths shallower than 40 meters and is often found in harbors and on natural substrates like docks and rocks.  As a filter feeder, Ciona robusta consumes phytoplankton, bacteria, and detritus by drawing water through its oral siphon and expelling it through the atrial siphon. This species has shown significant invasive tendencies, spreading to various regions worldwide, including the Pacific Northwest and parts of South America, Africa, and Europe. Its presence can negatively impact aquaculture due to fouling of equipment and competition with cultured species.