All about Tunicates & what they look like
Many tunicates look like exotic underwater plants, but they are actually a group of marine animals. Tunicates (also called sea squirts), are shaped like blobs or tubes, with two siphons on the top and an outer covering called a tunic. Tunicate species either live alone or in colonies. Solitary tunicates can get to six inches in length. Tunicates that live in colonies can spread over large areas ranging from a few square feet to acres.
What seems to be the problem?
Three species of non-native tunicates have the potential to harm important habitat in Puget Sound by crowding out ‘native species‘. Left unchecked, these invaders could cause serious economic damage to the critical habitat that forage and commercial species depend on. They could also affect important geoduck growing areas as well as other aquaculture operations.
Club Tunicates Transparent Ciona Tunicate Invasive Didemnum
Where are the Tunicates in the Puget Sound Region?
Club Tunicate – Two marinas in the Pacific Northwest have infestations to club tunicates.
Transparent Ciona Tunicate – First detected in March 2004, Ciona range throughout the lower portion of Hood Canal. These tunicates form dense mats and crowd out to other species. Extreme low dissolved oxygen events in September 2006 didn’t see, to adversely affect this tenacious tunicate.
Invasive Didemnum – Found in several locations around the Sound including Dabob Bay, Liberty Bay, Edmonds, Underwater Park, and the Shilshole and Des Moines marinas.
How did invasive tunicates get to Puget Sound?
Club Tunicate – Native to Asia. Probably introduced in discharged ballast water or as hitchhikers on ship hulls.
Transparent Ciona Tunicate – Native to Japan. Probably introduced in discharged ballast water or arrived as hitchhikers on hulls of ships.
Invasive Didemnum – Probably introduced with oysters or other shellfish stock and in discharged ballast water or arrived as hitchhikers on hulls of ships.
Fish and Wildlife hired commercial divers to remove infestations of club tunicates in 2006. Divers removed more than 90 pounds from almost all of the infested boats in four marinas. In addition, they surveyed about 30 000 square meters of docks in the infested marinas, cleaned about 33% of the area and removed about 2,000 pounds of invasive tunicates from the marina structure. The state needs to do more work to remove the remaining tunicates in these infested marinas.
Invasive Didemnum. Recreational divers under the guidance of the Edmonds Underwater Park docent look aggressive action to remove all known patches in the underwater park. They buried colonies, wrapped them in plastic and covered them in sheeting and introduced salt or chlorine tablets to get rid of them. The volunteers hauled out infested buoys and anchor lines onto the beach where the animals died.