AquaNISInformation system on aquatic non-indigenous and cryptogenic species |
Species | Styela clava [WoRMS] | |
Authority | Herdman, 1881 | |
Family | Styelidae | |
Order | Stolidobranchia | |
Class | Ascidiacea | |
Phylum | Chordata | |
Synonym (?) | Clubbed Tunicate | |
Sub-species level (?) | Not entered |
Native origin (?) | Ocean: Pacific --> Ocean region: NW Pacific References: Hewitt, C. L., Campbell, M. L., Thresher, R. E., Martin, R. B., Boyd, S., Cohen, B. F., ... & Lockett, M. M. (2004). Introduced and cryptogenic species in port Phillip bay, Victoria, Australia. Marine biology, 144(1), 183-202. Comments: Styela clava is a fouling organism native to the Pacific Coast of Asia. Because of its hardy nature and ability to withstand salinity and temperature fluctuations, Styela clava easily establishes wherever it is introduced. |
Life form / Life stage (?) |
References (not structured): Lützen J (1998) Styela clava Herdman (Urochordata, Ascidiacea), a successful immigrant to North West Europe: ecology, propagation and chronology of spread. Helgoländer Meeresuntersuchungen, Volume 52 Issue 3-4, 383 – 391pp Comments: S. clava is the second largest ascidian in NW Europe. The body is club-shaped and consists of an elongated oval body proper and a long tapering peduncle terminating in a discoid holdfast. Maximum length including the pe- duncle is 125 mm. The surface of the tunic on the peduncle and posterior part of the body is folded longitudinally, and on all other parts transversely wrinkled or irregularly grooved. |
Sociability / Life stage (?) |
References (not structured): Fuller P (2005) Styela clava. USGS-NAS (Nonindigenous Aquatic Species Database, Gainesville, FL.). http://nas.er.usgs.gov/queries/FactSheet.asp?SpeciesID=1292 Comments: Styela clava is a large, club-shaped solitary ascidian with a tough leathery body wall with conspicuous bumps, growing up to 160mm long. |
Reproductive frequency (?) | Iteroparous References (not structured): Lützen, J. (1998). Styela clava Herdman (Urochordata, Ascidiacea), a successful immigrant to North West Europe: ecology, propagation and chronology of spread. Helgoländer Meeresuntersuchungen, 52(3-4), 383-391. |
Reproductive type (?) | Sexual References: Dupont L, Viard F, Dowell M J, Wood C, Bishop JDD (2009) Fine- and regional-scale genetic structure of the exotic ascidian Styela clava (Tunicata) in southwest England, 50 years after its introduction. Molecular Ecology, Volume 18: 3, 442-453 pp Comments: Styela clava is hermaphroditic but male and female gonads mature at different times, hence they are not self-fertile. S. clava is hermaphroditic and oviparous with a pelagic lecithotrophic larval life of 24-28 h at 20°C. Styla clava produces larvae that can swim a few millimetres in short bursts of activity and settle on hard substrata after approximately 12 hour to develop into sessile juveniles. |
Developmental trait (?) | Lecithotrophy Spawning References: Dupont L, Viard F, Dowell M J, Wood C, Bishop JDD (2009) Fine- and regional-scale genetic structure of the exotic ascidian Styela clava (Tunicata) in southwest England, 50 years after its introduction. Molecular Ecology, Volume 18: 3, 442-453 pp Lützen, J. (1998). Styela clava Herdman (Urochordata, Ascidiacea), a successful immigrant to North West Europe: ecology, propagation and chronology of spread. Helgoländer Meeresuntersuchungen, 52(3-4), 383-391. Comments: Lecitotrophic larval life of 24-28 h. The gonads are closely applied to the visceral surface of the body wall. It reproduces sexually, is oviparous and larval development is usually of one day duration. Spawning in S. clava is temperature dependant and it is believed to only be able to spawn in waters above 15°C. Fertilisation is external and eggs and larvae planktonic for between one to three days, after which they settle and metamorphose into the sessile adult. Reproduction occurs throughout all but the coldest periods. S. clava can live 2-3 years and reach maturity around 10 months. Since S. clava eggs hatch 12–15 hour after spawning/fertilization, the total pelagic dispersal time for the developing egg/embryo and larva is between 24 and 43 hour |
Characteristic feeding method / Life stage (?) |
Comments: Styela clava is a suspension feeder that consumes matter such as phytoplankton, zooplankton, oyster larvae and other suspended organic materials. |
Mobility / Life stage (?) |
References (not structured): Dupont L, Viard F, Dowell M J, Wood C, Bishop JDD (2009) Fine- and regional-scale genetic structure of the exotic ascidian Styela clava (Tunicata) in southwest England, 50 years after its introduction. Molecular Ecology, Volume 18: 3, 442-453 pp Comments: They are poor swimmers and normally settle near to parent populations. It can attach itself to concrete and cement, wood, vessel hulls and reefs. S. clava has also frequently been found on permanently submerged floating surfaces, such as buoys and pontoons. |
Salinity tolerance range (?) | Venice system: 6. Polymixohaline [18-30psu] References: Paavola M, Olenin S, Leppäkoski E (2005) Are invasive species most successful in habitats of low native species richness across European brackish water seas? Estuarine, Coastal and Shelf Science 64 (2005) 738-750 Leppakoski E, Olenin S (2000) Non-native species and rates of spread: lessons from the brackish Baltic Sea. Biological Invasions, 2: 151-163 |
Habitat modifying ability potential (?) | Autogenic ecosystem engineers Keystone species References: JNCC (Joint Nature Conservation Committee) (1997) Non-native marine species in British waters: a review and directory. Editors: N. Clare Eno, Robin A. Clark & William G. Sanderson. http://www.jncc.gov.uk/page-1722 Comments: When Styela clava populations explode they often out-compete many native species for food. S. clava can reach densities of 500-1500 individuals per square metre. These extreme densities can have negative impacts on native and aquaculture species through competition for space and food, as well as predation of larvae from the water column. It can also occur as fouling on vessels, aquaculture and fishing equipment and other artificial structures. Dense fouling on fishing equipment, moorings, ropes, etc. can be time consuming to remove and can result in tangling of fishing gear. Hull fouling increases drag on vessels, requires an increase in the frequency of hull cleaning, and increases fuel costs. In Japan it has been known to impact human health causing an asthmatic condition in oyster shuckers when hammering open Styela fouled oysters in poorly ventilated areas. Due to its considerable body length, even medium-sized specimens stand clear of almost all other sessile organisms on a surface. This not only makes it more competitive as a filtrator, but may also allow it to eliminate larvae of co-inhabiting species from the plankton. Since the introduction of S. clara to the south coast of England, the increase in its number seems to have been paralleled by a decline in the population of another ascidian, Ciona intestinalis. |
Toxicity / Life stage (?) | Not relevant References: Fuller, P (2005) Styela clava. USGS-NAS (Nonindigenous Aquatic Species Database, Gainesville, FL.). http://nas.er.usgs.gov/queries/FactSheet.asp?SpeciesID=1292 Comments: Styela clava is eaten as seafood in Korea. |
Bioaccumulation association (?) | Unknown Comments: Not available. |
Known human health impact? | Not known References: AquaNIS. Editorial Board, 2015. Information system on Aquatic Non-Indigenous and Cryptogenic Species. World Wide Web electronic publication. www.corpi.ku.lt/databases/aquanis. Version 2.36+. Accessed 2021-08-31. Clarke, C. L., & Therriault, T. W. (2007). Biological synopsis of the invasive tunicate Styela clava (Herdman 1881). Fisheries and Oceans Canada, Science Branch, Pacific Region, Pacific Biological Station. Davis, M. H., & Davis, M. E. (2010). The impact of the ascidian Styela clava Herdman on shellfish farming in the Bassin de Thau, France. Journal of Applied Ichthyology, 26, 12-18. DOI: 10.1111/j.1439-0426.2010.01496.x Fuller, P (2005) Styela clava. USGS-NAS (Nonindigenous Aquatic Species Database, Gainesville, FL.). http://nas.er.usgs.gov/queries/FactSheet.asp?SpeciesID=1292 Lützen J (1998) Styela clava Herdman (Urochordata, Ascidiacea), a successful immigrant to North West Europe: ecology, propagation and chronology of spread. Helgoländer Meeresuntersuchungen, Volume 52, Issue 3-4, 383 – 391 pp Comments: No (used as seafood) (Fuller et al., 2005). |
Known economic impact? | Known References: AquaNIS. Editorial Board, 2015. Information system on Aquatic Non-Indigenous and Cryptogenic Species. World Wide Web electronic publication. www.corpi.ku.lt/databases/aquanis. Version 2.36+. Accessed 2021-08-31. Clarke, C. L., & Therriault, T. W. (2007). Biological synopsis of the invasive tunicate Styela clava (Herdman 1881). Fisheries and Oceans Canada, Science Branch, Pacific Region, Pacific Biological Station. Davis, M. H., & Davis, M. E. (2010). The impact of the ascidian Styela clava Herdman on shellfish farming in the Bassin de Thau, France. Journal of Applied Ichthyology, 26, 12-18. DOI: 10.1111/j.1439-0426.2010.01496.x Fuller, P (2005) Styela clava. USGS-NAS (Nonindigenous Aquatic Species Database, Gainesville, FL.). http://nas.er.usgs.gov/queries/FactSheet.asp?SpeciesID=1292 Lützen J (1998) Styela clava Herdman (Urochordata, Ascidiacea), a successful immigrant to North West Europe: ecology, propagation and chronology of spread. Helgoländer Meeresuntersuchungen, Volume 52, Issue 3-4, 383 – 391 pp Comments: Reducing oyster production in aquaculture (Davis et al., 2010). |
Known measurable environmental impact? | Known References: AquaNIS. Editorial Board, 2015. Information system on Aquatic Non-Indigenous and Cryptogenic Species. World Wide Web electronic publication. www.corpi.ku.lt/databases/aquanis. Version 2.36+. Accessed 2021-08-31. Clarke, C. L., & Therriault, T. W. (2007). Biological synopsis of the invasive tunicate Styela clava (Herdman 1881). Fisheries and Oceans Canada, Science Branch, Pacific Region, Pacific Biological Station. Davis, M. H., & Davis, M. E. (2010). The impact of the ascidian Styela clava Herdman on shellfish farming in the Bassin de Thau, France. Journal of Applied Ichthyology, 26, 12-18. DOI: 10.1111/j.1439-0426.2010.01496.x Fuller, P (2005) Styela clava. USGS-NAS (Nonindigenous Aquatic Species Database, Gainesville, FL.). http://nas.er.usgs.gov/queries/FactSheet.asp?SpeciesID=1292 Lützen J (1998) Styela clava Herdman (Urochordata, Ascidiacea), a successful immigrant to North West Europe: ecology, propagation and chronology of spread. Helgoländer Meeresuntersuchungen, Volume 52, Issue 3-4, 383 – 391 pp Comments: Impacts by competing for space and food with native species (Clarke et al., 2007). |
Included in the Target Species list? | Yes Comments: Assessed by the COMPLETE project experts (2021), included in target species list. |
Association with vessel vectors (?) | Ballast waters Biofouling References: Lützen J (1998) Styela clava Herdman (Urochordata, Ascidiacea), a successful immigrant to North West Europe: ecology, propagation and chronology of spread. Helgoländer Meeresuntersuchungen, Volume 52, Issue 3-4, 383 – 391 pp Comments: It can also occur as fouling on vessels, aquaculture and fishing equipment and other artificial structures. Dense fouling on fishing equipment, moorings, ropes, etc. can be time consuming to remove and can result in tangling of fishing gear. Hull fouling increases drag on vessels, requires an increase in the frequency of hull cleaning, and increases fuel costs. Probably introduced to Europe as fouling on warships arriving during the Korean War in 1952. Known to occur on ship and leisure craft hulls and may be spread with oyster stock movements. Local transmissions in ships' ballast water is possible (DAISIE). Movement of floating port structures and specimen from drifting Sargassum muticum may also result in spread |
Molecular information | Available Genbank: https://www.ncbi.nlm.nih.gov/nuccore/?term=Styela+clava; BOLD: http://www.boldsystems.org/index.php/Public_SearchTerms |
Last update by | Monika Pelėdienė, 2022-01-21 |