Styela plicata is a tropical to temperate tunicate that has invaded the Gulf of Mexico by hitching a ride on ships' hulls. This sessile filter feeder can expel water when threatened, leading to the name “sea squirt.” This species is rather hardy; “able to tolerate changes in seawater between 10°-30°C and salinites between 22%-34%” (Thiyagarajan & Qian, 2003) as well as pollution and brackish water. This species is difficult to manage because of the large amount of fluctuation in its population; a colony may be large one year and absent the next. Preventative measures include anti-fouling paints, wood preservation, and slime control containing tributyltin.