Styela clava

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Styela clava
Styela clava.JPG
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Subphylum: Tunicata
Class: Ascidiacea
Order: Stolidobranchia
Family: Styelidae
Genus: Styela
Species:
S. clava
Binomial name
Styela clava
Herdman, 1881

Styela clava is a solitary, subtidal ascidian tunicate. [1] It has a variety of common names such as the stalked sea squirt, clubbed tunicate, Asian tunicate, leathery sea squirt, or rough sea squirt. As its common names suggest, S. clava is club-shaped with an elongated oval body and a long peduncle for attaching to a substrate. [1] Although native to the northwestern waters of the Pacific Ocean, since the 1900s, S. clava has become an increasingly successful invasive species outside of its native range. [2] [3] It is edible.

Contents

Morphology

S. clava is a solitary tunicate. Including both the club-shaped body and peduncle, larger specimen of S. clava can have a maximum length of around 130 mm (5.1 in) and smaller specimen only reaching 30 mm (1.2 in) in length. [1] Smaller specimen tend to have no distinct peduncle. As described by some of its common names, S. clava has a tough, wrinkled or irregularly grooved skin and comes in two variations of color dependent on size. Larger specimen have a light brown body and a darker brown peduncle while smaller specimen are yellow-brown. [1]

Habitat

S. clava is a marine invertebrate animal. Adults are entirely sessile, growing attached to hard subtidal substrata as deep as 25 meters (82 ft). They can be found on virtually any hard surface such as rocks, buoys, pilings and shells of mussels. S. clava is predominant in the littoral zone, preferring sheltered localities free of strong wave action and floating objects, making artificial surfaces in harbors and marinas exceptional habitat. [1] [4] [5]

It is a hardy species that can live in a wide range of temperatures from -2 °C to 27 °C and can tolerate high salinity waters (26% - 28% salinity) that would be lethal to other tunicate species. [1]

Reproduction

Like most tunicates, S. clava is hermaphroditic and produces short-lived pelagic lecithotrophic larvae. [1] [2] [5] They reproduce externally via broadcast spawning, and the reproductive period is highly dependent on sea surface temperatures reaching a critical temperature threshold, between 16 °C and 20°C. [5] [2] The reproductive period can vary from 4 to 10 months depending on location. Along the Californian coast in the United States, the reproduction period occurs for 4 months from June to September, while in Denmark and England, the reproduction period is also 4 months but occurs from July to October. [5]

Native Range

S. clava is native to the northwestern waters of the Pacific, particularly the seas and coasts of Japan and Korea, to Siberia, and as far south as the coasts off Shanghai, China. [2] [3] [6]

Invasions

Outside of its native range, S. clava has proven to be an increasingly successful invasive species due to physiological adaptations and environmental tolerances. S. clava's thick tunic, relative to native tunicates, provides better protection from possible predators and helps prevent desiccation. [1] It can withstand subzero to 23 °C sea temperatures and high salinity water, giving it strong tolerance to environmental changes in water. [1] [7] The lack of a natural predator already gives S. clava an advantage over native tunicates, but their large size as well allows them to outcompete other filter-feeding species such as oysters or mussels for food and substrate space. [1]

Range

Since the mid-1900s, S. clava has been unintentionally introduced globally to temperate coastal waters outside of its native range. It has successfully established stable populations on both coasts of North America, Europe, New Zealand, Australia, and Argentina.

The earliest sighting of S. clava outside of its natural range was on the United States’ west coast in Californian coastal waters in the early-1900s. [8] [4] Since then, the invasive tunicate has spread as far south as Baja, Mexico and as far north as Vancouver Island, Canada. S. clava populations in North America’s Atlantic waters is believed to have been introduced around the 1970s. [7]

In the mid-1900s, the next sighting of S. clava was recorded in European waters in Britain. In the span of 25 years, S. clava populations have expanded their range in the coastal waters of the United Kingdom and to mainland Europe. The current European countries with established S. clava populations are England, Ireland, Belgium, Netherlands, Denmark, France, Portugal and Spain. [3] [9] [7]

Vectors

For each region there are multiple pathways by which S. clava could have been introduced. Although not definitive, S. clava's new population distribution is most likely due to anthropogenic vectors. [6] [7] The introduction of S. clava was most likely the result of direct introduction from Japan through shellfish transfers or ship fouling. [8] [4] In Europe, the source of introduction is believed to be from the hulls of military ships returning from the Korean War. [8] [3] As waters are becoming warmer due to climate change, there is concern of habitat expansion into previously unoccupied waters. [9]

Effects

Successful introduction and establishment of populations outside of its natural range can cause dramatic changes in the structure and composition of benthic communities. [4] It is dominating fouling communities, leading to population declines in other filter-feeding species, leading to lower biodiversity. [2] [1] [4] S. clava is a solitary species, but with optimal conditions can reach high densities, up to 500 - 1,000 individuals, fouling man-made substrates resulting in boat and fishing gear difficulties. [7]

They also pose a threat to aquaculture, which is being seen in European waters. In Bassin de Thau, France (Étang de Thau), S. clava is becoming a management problem as they pose a threat to oyster and mussel farming by outcompeting the shellfish for food and substrate space. [3]

Related Research Articles

<span class="mw-page-title-main">Tunicate</span> Marine animals, subphylum of chordates

A tunicate is an exclusively marine invertebrate animal, a member of the subphylum Tunicata. This grouping is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords. The subphylum was at one time called Urochordata, and the term urochordates is still sometimes used for these animals. They are the only chordates that have lost their myomeric segmentation, with the possible exception of the seriation of the gill slits. However, doliolids still display segmentation of the muscle bands.

<span class="mw-page-title-main">Ascidiacea</span> Paraphyletic group of tunicates comprising sea squirts

Ascidiacea, commonly known as the ascidians or sea squirts, is a paraphyletic class in the subphylum Tunicata of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic" made of a polysaccharide.

<i>Ciona intestinalis</i> Species of ascidian

Ciona intestinalis is an ascidian, a tunicate with very soft tunic. Its Latin name literally means "pillar of intestines", referring to the fact that its body is a soft, translucent column-like structure, resembling a mass of intestines sprouting from a rock. It is a globally distributed cosmopolitan species. Since Linnaeus described the species, Ciona intestinalis has been used as a model invertebrate chordate in developmental biology and genomics. Studies conducted between 2005 and 2010 have shown that there are at least two, possibly four, sister species. More recently it has been shown that one of these species has already been described as Ciona robusta. By anthropogenic means, the species has invaded various parts of the world and is known as an invasive species.

<i>Styela</i> Genus of tunicates

Styela is a genus of tunicates. Styela clava, an edible species, is known as an invasive species in some areas.

<i>Botrylloides violaceus</i> Species of sea squirt

Botrylloides violaceus is a colonial ascidian. It is commonly known as the chain tunicate, but has also been called several other common names, including: lined colonial tunicate, orange sheath tunicate, orange tunicate, and violet tunicate. Its native range is in the northwest Pacific from southern China to Japan and Siberia. Colonies grow on solid substrates and consist of individuals arranged in twisting rows. Outside its native range, it is considered an invasive species and is becoming more common in coastal waters of North America and other waters around the world, likely being spread by shipping industries.

<span class="mw-page-title-main">Aquatic invasive species in Canada</span>

Canadian aquatic invasive species are all forms of life that traditionally has not been native to Canada's waterways. In Eastern Canada, non-native plant and animal species are a concern to biologists. Bringing non-native species such as invasive fishes into Canada can damage the environment and ecosystem by repressing native species due to food competition or preying. Invasive fishes enter the fresh waters of Canada in several ways including drifting, deliberate introduction, accidental release, experimental purposes and, most commonly, through the attachment on international boat hulls. Invasive species are the second biggest threat to fish and other marine life in Canada behind loss of habitat and degradation. The threat to native species is primarily caused by impacts on the food web; however, invasive species also bring dangerous pathogens and physically interfere with existing aquatic life. Invasive species include sea lampreys, zebra mussels, smallmouth bass, European green crab, vase tunicate, and sea squirts.

<i>Styela plicata</i> Species of sea squirt

Styela plicata, commonly known as pleated sea squirt, is a species of tunicate in the family Styelidae. This sessile filter feeder can expel water when threatened.

<i>Styela montereyensis</i> Species of tunicate

Styela montereyensis, also called the stalked tunicate, Monterey stalked tunicate, and the long-stalked sea squirt is a solitary ascidian tunicate. It has a cylindrical, yellow to dark reddish-brown body and a thin trunk that anchors it to rocks. It is found in subtidal areas of the western coast of North America from Vancouver Island to Baja California.

<i>Ecteinascidia turbinata</i> Species of sea squirt

Ecteinascidia turbinata, commonly known as the mangrove tunicate, is a species of tunicate in the family Perophoridae. It was described to science in 1880 by William Abbott Herdman. The cancer drug trabectedin can be isolated from this species.

<i>Didemnum molle</i> Species of sea squirt

Didemnum molle is a species of colonial tunicate in the family Didemnidae. It is commonly known as the tall urn ascidian, the green barrel sea squirt or the green reef sea-squirt. It is native to the Red Sea and the tropical waters of the Indo-Pacific region.

<i>Didemnum vexillum</i> Species of sea squirt

Didemnum vexillum is a species of colonial tunicate in the family Didemnidae. It is commonly called sea vomit, marine vomit, pancake batter tunicate, or carpet sea squirt. It is thought to be native to Japan, but it has been reported as an invasive species in a number of places in Europe, North America and New Zealand. It is sometimes given the nickname "D. vex" because of the vexing way in which it dominates marine ecosystems when introduced into new locations; however, the species epithet vexillum actually derives from the Latin word for flag, and the species was so named because of the way colonies' long tendrils appear to wave in the water like a flag.

<i>Ciona savignyi</i> Species of sea squirt

Ciona savignyi is a marine animal sometimes known as the Pacific transparent sea squirt or solitary sea squirt. It is a species of tunicates in the family Cionidae. It is found in shallow waters around Japan and has spread to the west coast of North America where it is regarded as an invasive species.

<i>Pyura pachydermatina</i> Species of sea squirt

Pyura pachydermatina is a sea tulip, a solitary species of tunicate in the suborder Stolidobranchia. It is native to shallow waters around New Zealand.

<i>Styela angularis</i> Species of sea squirt

Styela angularis is a solitary, hermaphroditic ascidian tunicate that is found along the coast of Southern Africa from Lüderitz Bay in Namibia to the Eastern Cape.

Polyandrocarpa is a genus of ascidian tunicates within the family Styelidae.

<i>Molgula manhattensis</i> Species of sea squirt

Molgula manhattensis, commonly known as "sea grapes", is a species of ascidian commonly found along the East Coast and Gulf Coast region of the United States. Although it is native to this region, it has been introduced to other areas of Europe, Australia, and the West Coast.

<i>Ciona robusta</i> Species of sea squirt

Ciona robusta is a species of marine invertebrate in the genus Ciona of the family Cionidae. The holotype was collected on the northeastern coast of Honshu Island, Japan. Populations of Ciona intestinalis known as Ciona intestinalis type A found in the Mediterranean Sea, the Pacific Ocean, east coast of North America, and the Atlantic coasts of South Africa have been shown to be Ciona robusta.

<i>Cnemidocarpa finmarkiensis</i> Species of sea squirt

Cnemidocarpa finmarkiensis is a species of solitary ascidian tunicate in the family Styelidae. Common names include broad base sea squirt, orange sea squirt, red sea squirt, shiny orange sea squirt, shiny red tunicate and Finmark's tunicate. It is native to shallow waters in the northern and northeastern Pacific Ocean.

<i>Pyura haustor</i> Species of chordates

Pyura haustor is a species of sessile ascidian, or sea squirt, that lives in coastal waters in the north-eastern Pacific Ocean, attached to rocks or artificial structures. Common names for this species include the wrinkled seapump, the wrinkled sea squirt and the warty tunicate.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 Lützen, J. (1998-09-01). "Styela clava Herdman (Urochordata, Ascidiacea), a successful immigrant to North West Europe: ecology, propagation and chronology of spread". Helgoländer Meeresuntersuchungen. 52 (3): 383–391. doi: 10.1007/BF02908912 . ISSN   1438-3888.
  2. 1 2 3 4 5 Bourque, Daniel; Davidson, Jeffrey; MacNair, Neil G.; Arsenault, Garth; LeBlanc, Angeline R.; Landry, Thomas; Miron, Gilles (2007-03-26). "Reproduction and early life history of an invasive ascidian Styela clava Herdman in Prince Edward Island, Canada". Journal of Experimental Marine Biology and Ecology. Proceedings of the 1st International Invasive Sea Squirt Conference. 342 (1): 78–84. doi:10.1016/j.jembe.2006.10.017. ISSN   0022-0981.
  3. 1 2 3 4 5 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 (s2): 12–18. doi: 10.1111/j.1439-0426.2010.01496.x . ISSN   1439-0426.
  4. 1 2 3 4 5 Dupont, L.; Viard, F.; Davis, M. H.; Nishikawa, T.; Bishop, J. D. D. (2010-08-01). "Pathways of spread of the introduced ascidian Styela clava (Tunicata) in Northern Europe, as revealed by microsatellite markers". Biological Invasions. 12 (8): 2707–2721. doi:10.1007/s10530-009-9676-0. ISSN   1573-1464. S2CID   41427593.
  5. 1 2 3 4 Wong, Nicholas A.; McClary, Dan; Sewell, Mary A. (2011-12-01). "The reproductive ecology of the invasive ascidian, Styela clava, in Auckland Harbour, New Zealand". Marine Biology. 158 (12): 2775–2785. doi:10.1007/s00227-011-1776-6. ISSN   1432-1793. S2CID   84083301.
  6. 1 2 Goldstien, S. J.; Schiel, D. R.; Gemmell, N. J. (2010). "Regional connectivity and coastal expansion: differentiating pre-border and post-border vectors for the invasive tunicate Styela clava". Molecular Ecology. 19 (5): 874–885. doi:10.1111/j.1365-294X.2010.04527.x. ISSN   1365-294X. PMID   20149095. S2CID   29293465.
  7. 1 2 3 4 5 Locke, Andrea; Hanson, J. Mark; Ellis, Karla M.; Thompson, Jason; Rochette, Rémy (2007-03-26). "Invasion of the southern Gulf of St. Lawrence by the clubbed tunicate (Styela clava Herdman): Potential mechanisms for invasions of Prince Edward Island estuaries". Journal of Experimental Marine Biology and Ecology. Proceedings of the 1st International Invasive Sea Squirt Conference. 342 (1): 69–77. doi:10.1016/j.jembe.2006.10.016. ISSN   0022-0981.
  8. 1 2 3 Dupont, L.; Viard, F.; Dowell, M. J.; Wood, C.; Bishop, J. D. D. (2009). "Fine- and regional-scale genetic structure of the exotic ascidian Styela clava (Tunicata) in southwest England, 50 years after its introduction". Molecular Ecology. 18 (3): 442–453. doi:10.1111/j.1365-294X.2008.04045.x. ISSN   1365-294X. PMID   19161467. S2CID   33337021.
  9. 1 2 Turon, Xavier; Cañete, Juan; Sellanes, Javier; Rocha, Rosana; López-Legentil, Susanna (2016). "Too cold for invasions? Contrasting patterns of native and introduced ascidians in subantarctic and temperate Chile". Management of Biological Invasions. 7 (1): 77–86. doi: 10.3391/mbi.2016.7.1.10 . hdl: 10261/129514 .
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