Styela clava

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Styela clava
Styela clava.JPG
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Tunicata
Class: Ascidiacea
Order: Stolidobranchia
Family: Styelidae
Genus: Styela
Species: S. clava
Binomial name
Styela clava[1]
Herdman, 1881

The stalked sea squirt (Styela clava), also known as the club sea squirt, club tunicate, Asian tunicate, leathery sea squirt or rough sea squirt, is a solitary, hermaphroditic, ascidian tunicate that is native to the Pacific coast of Asia, ranging from the Sea of Okhotsk to Japan, Korea and northeast China.[2][3] It has been introduced widely around the world such as off Australia,[4] New Zealand,[5] both coasts of North America,[6] and Europe.[7] It is considered invasive outside the native range, as adults lack natural predators, can outcompete native animals, feed on their planktonic larvae, and foul fishing gear and boats.[2][3] In the most extreme cases, it can reach densities of up to 1,500 per square meter (140 per square foot).[2]

Styela clava is a hardy species that can live at temperatures between −2 and 27 °C (28–81 °F), but only breeds above 15 °C (59 °F). Additionally, adults can survive in both marine and brackish water at salinities down to 10 ppt, although breeding only occurs above 25 ppt.[3]

These sea squirts are characterized by their brown or yellow, rough and wrinkled surface. They typically have a length of 8–12 cm (3.1–4.7 in), but can reach up to 20 cm (7.9 in).[3] They can be found on virtually any hard surface (such as rocks, buoys, pilings and shells of mussels) and occasionally on seaweed.[3] It may have been carried to New England waters from Europe (where it arrived in the early 1950s) in ballast water or ship fouling.[8]

Styela clava is called mideodeok (미더덕) in Korea where it is eaten[3] and part of the local dish agujjim.

Behavior[edit]

Populations around Los Angeles, California grow 1–1.5 cm (0.4–0.6 in) per month in the first half year, reaching maturity and slowing growth at about 9 cm (3.5 in) in size. Broadcast spawning occurs late spring to early fall. They occur to a depth of at least 25 m (82 ft), and filter approximately 150 mL of water / minute / gram body weight.[9]

References[edit]

  1. ^ "Styela clava". Integrated Taxonomic Information System. Retrieved February 17, 2007. 
  2. ^ a b c Global Invasive Species Database: Styela clava. Retrieved 21 April 2016
  3. ^ a b c d e f The Exotic Guide: Styela clava. Retrieved 21 April 2016.
  4. ^ Hewitt, C.; et al. (1999). "Marine biological invasions of Port Phillip Bay, Victoria.". Centre for Research on Introduced Marine Pests CSIRO Technical Report (20): 344. 
  5. ^ Davis MH and Davis ME (2006). "Styela clava (Tunicata: Ascidacea) a new edition to the fauna of New Zealand.". Porcupine Marine Natural History Society Newsletter 20: 23–28. 
  6. ^ Wonham MJ and Carlton JT (2005). "Trends in marine biological invasions at local and regional scales: the Northeast Pacific Ocean as a model system.". Biological Invasions 7 (3): 369–392. doi:10.1007/s10530-004-2581-7. 
  7. ^ Davis MH and Davis ME (2005). "Styela clava (Tunicata: Ascidacea) a new edition to the fauna of the Portuguese coast". Journal of the Marine Biological Association of the United Kingdom 85 (2): 403–404. doi:10.1017/S002531540501132Xh. 
  8. ^ RH Morris, DP Abbott & EC Haderlie. 1980. Intertidal Invertebrates of California. Stanford University Press: Stanford, CA. p. 207-208.

External links[edit]