Stalked Tunicate, Styela montereyensis

The Stalked Tunicate (Styela montereyensis), also known as the Monterey Stalked Tunicate or the Long-stalked Sea Squirt, is a species of solitary ascidian tunicate that occurs from Vancouver Island to Baja California in the Pacific Ocean and some inland waters.

It lives in the low intertidal zone up to 120 feet deep. It is fairly common within its range, and can be found firmly attached to substrate, pilings, jetties and subtidal reefs, in waters ranging from calm to extremely turbulent. Specimens in the Pacific Northwest rarely occur in inland waters, but are normally found in the outer straits and open coast.

This tunicate is yellow to dark red-brown in color. It is mainly solitary, but will often grow in loose groups. It is 3.15 to 6 inches long in exposed sites, but can grow larger, up to 10 inches in much calmer habitats. The body is elongated and cylindrical, and is attached to a thinner stalk approximately the same length as the body. Its siphons are close together at the distal end, with its oral siphon pointing to the side or downward. The atrial siphon points straight upward. It has a leathery tunic displaying noticeable longitudinal grooves and ridges that extend down the entire length of the body.

This species is commonly corrupted with foreign matter and small organisms such as algae and hydroids when occurring in harbors, but remains clean in wave-swept habitats.

Image Caption: Sea Squirt Ascidiacea,Styela montereyensis with Ostrich plume hydroid, colonial cnidarians Aglaophenia in California. Credit: Brocken Inaglory/Wikipedia(CC BY-SA 3.0)