Pleated Sea Squirt (Styela plicata) — identification, habitat & look-alikes

The pleated sea squirt is a lumpy, stalkless sea squirt that crowds onto docks, pilings, and boat hulls in warm harbors around the world. In the US it lives along the southeastern Atlantic coast, in the Gulf of Mexico, and in Southern California harbors, where it was first recorded in 1915.

Appearance

Appearance: An oval, stalkless sea squirt up to about 3.5 in (9 cm) long, grayish or tan-white, with a thick, leathery covered in lumps and wrinkles. Its two short, four-lobed have red or purple stripes.

Look-alikes

Club tunicateStyela clava

The club tunicate is club-shaped and usually has a stalk (young ones may not). The pleated sea squirt is oval and stalkless, with more lumps.

Why they get mixed upSame genus, similar leathery, bumpy skin, and both foul harbors.

Long-stalked sea squirtStyela montereyensis

It is the only similar species that attaches by a stalk, a long one that blends gradually into the body; the pleated sea squirt has no stalk.

Rough sea squirtStyela canopus

It is much smaller (up to about 1.2 in, 3 cm), usually smooth-skinned and reddish brown, while the pleated sea squirt is whitish to tan and very lumpy.

Styela gibbsii

A native West Coast species that is also stalkless but smaller (up to about 1.5 in, 4 cm). In southern California it is usually found in deeper water rather than on harbor floats.

Where it lives

Typical habitats: Harbor floats and pilings
Docks and marinas
Oyster reefs
Rocky surfaces
Range: Found in warm seas worldwide, spread largely by hitching rides on ship hulls; its original home is still debated, with the northwest Pacific the leading idea. In the US it is abundant in the northern Gulf of Mexico. In California it occurs on harbor floats and pilings from Santa Barbara to San Diego, and it has been reported recently from South Carolina (2008) and the Delmarva coast of Maryland and Virginia (2023).
Preferred conditions: Lives in water from about 50 to 86°F (10–30°C), from the low tide line down to about 100 ft (30 m). It handles polluted and brackish water. Where it shares a bay with the club tunicate, it tends to sit farther from the mouth, in calmer water.

Behavior

Diet: A that strains tiny food particles from the water it pumps through its body.
Activity: Stays attached in one place and squirts water when disturbed.
Social life: Each animal is separate, but they often grow in dense clumps.

Life cycle

Reproduction: Reproduces only by eggs and sperm, not by budding. The tadpole-like larvae are about 1/16 in (1.3 mm) long before they settle.
Time to maturity: In lab studies, young reached maturity in about 2 months in summer and 5 months in winter.
Lifespan: Adults live about 3–4 months after maturing.

Conservation

IUCN Red List: NENot EvaluatedNot yet assessed

Culture and stories

Culture and stories: In Korea, where it is called omandungi, it is sometimes used as a cheaper stand-in for the closely related club tunicate in seafood stews and braised dishes.