Invasion History

First Non-native North American Tidal Record: 1897
First Non-native West Coast Tidal Record: 1897
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Ciona robusta was formerly considered to be Ciona intestinalis. Morphological, ecological, and genomic data indicated that populations of C. intestinalis from the Mediterranean and the Pacific Ocean ('Sp. A') were similar to each other, but differed from the typical C. intestinalis ('Sp. B') from the coast of Northern Europe and the East Coast of North America (Dybern 1965; Boffelli et al. 2004; Suzuki et al. 2005; Caputi et al. 2007; Nydam and Harrison 2007; Nydam and Harrison 2010). Genetic analyses indicate that the two species have been largely isolated for 3-5 million years (Nydam and Harrison 2007; Roux et al. 2013). Brunetti et al. (2015) used morphological and genetic data to identify 'Sp. A' as C. robusta described by Hoshino and Tokioka (1967) from Japan.

Tentatively, we assign the Northwest Pacific as the native region of C. robusta (Gretchen Lambert, personal communication). Ciona robusta was collected in Yokohama, Japan, in 1902 (Hoshino and Nishikawa 1985), and has been regarded as an introduced species in Japan and Korea (Asakura 1992; Lee and Shin 2014; Pyo et al. 2012). It was collected very early in the Mediterranean (Savigny 1816, Heller 1875, Traustedt 1882, Roule 1884, all cited by Hoshino and Nishikawa 1985), but that may reflect the early development of oceanic trade between Europe and Asia. Further genomic studies may revise our ideas of C. robusta's origin and invasion history.

Ciona robusta was first collected in Australia in 1878 (Kott 1990), followed by the West Coast of North America in 1897 (San Diego, Wheeler 1897, cited by Carlton 1979), Hawaii in 1933 (Edmondson 1933, cited by Carlton and Eldredge 2009), Atlantic South America in 1945 (Argentina, Orensanz et al. 2002), New Zealand in 1950 (Cranfield et al. 1998), South Africa in 1955 (Millar 1955, cited by Monniot et al. 2001), and Pacific South America in 2002 (Castilla et al. 2005). Ciona robusta is a widespread and abundant fouling organism in harbors in the warmer parts of the world, while C. intestinalis seems better adapted to cooler regions (Dybern 1967; Marin et al. 1987; Caputi et al. 2007; Zhan et al. 2010).

North American Invasion History:

Invasion History on the West Coast:

Molecular identifications of C. robusta as 'C. intestinalis sp. A' have been made on specimens from Half Moon Bay, Sausalito (in San Francisco Bay; Nydam and Harrison 2007), and Santa Barbara Harbor (Caputi et al. 2007; Zhan et al. 2010), California. We assume, provisionally, that all the established West Coast populations are C. robusta. However, additional genetic sampling is desirable. Ciona robusta (up to now, reported as C. intestinalis) was first reported by Wheeler 1897 (cited by Carlton 1979) from San Diego Bay, 'growing in masses on pilings at Coronado' (Carlton 1979). It was subsequently found in San Diego by many other authors (Morgan 1905; Ritter and Forsyth 1917; Morgan 1941; Farmer 1964, all cited by Carlton 1979; Lambert and Lambert 1998; Lambert and Lambert 2003). This tunicate seems to have spread first to harbors with more shipping or boat traffic, including: San Francisco Bay (in 1932, Rodholm 1932, cited by Carlton 1979); Los Angeles-Long Beach (Barnard 1958); and Newport Bay (MacGinitie 1939, cited by Carlton 1979). Then it spread to smaller, more isolated harbors, including: Mission Bay (Farmer 1964, cited by Carlton 1979); Morro Bay (in 1968, Needles 2007); Santa Barbara Harbor, King Harbor (in 1970, Fay and Johnson 1971, cited by Carlton 1979); and Monterey Harborf (in 1974, Haderlie and Donat 1978). By 2000-2010, C. robusta was recorded in every sampled mainland harbor from San Diego to Bodega Bay, although its appearance was sporadic in some (Lambert and Lambert 1998; Fairey et al. 2002; Lambert and Lambert 2003; de Rivera et al. 2005a). In San Francisco Bay, it has been found in Lake Merritt, Central bay, and South Bay (Carlton 1979; Nydam and Harrison 2007; Chang 2009; Foss 2009), but we have not found reports from San Pablo Bay.

The occurrence of C. robusta north of Bodega Bay is uncertain. In Humboldt Bay, Boyd et al. reported only C. intestinalis, while Fairey et al. reported both C. intestinalis and C. savignyi. (Boyd et al. 2002; Fairey et al. 2002). However, it has not been found on SERC fouling plates in Humboldt Bay (Ruiz et al., unpublished data). There are old records from Haida Gwaii (Queen Charlotte Islands) and Vancouver Island, British Columbia and the San Juan Archipelago, Washington (Huntsman 1912, Fraser 1932, all cited by Carlton 1979). These records are historical and the current northern range edge of this species is unknown (Carlton 1979; Gretchen Lambert, personal communication).

Invasion History in Hawaii:

Ciona robusta (then identified as C. intestinalis) was recorded from Pearl and Honolulu harbors, Oahu by 1933 (Edmondson 1933, cited by Carlton and Eldredge 2009). It was found on the hull of a ship (USS Dobin) in Pearl Harbor in 1940 (Abbott 1941, cited by Carlton and Eldredge 2009) and has also been found in Kaneohe Bay (Abbott 1997, cited by Carlton and Eldredge 2009). It should be noted, that to our knowledge, molecular identifications have not been made.

Invasion History Elsewhere in the World:

As noted above, we are considering Ciona robusta native to the Northwest Pacific and introduced in European waters. This tunicate was collected in Egyptian waters as early as 1816, and was widespread in the Mediterranean Sea by the late 1800s, based on the synonyms listed by Hoshino and Nishikawa (1985). Its occurrence in the Black Sea is uncertain, since the only specimens in a molecular analysis were assigned to the cryptic 'Species D' (Zhan et al. 2010). On the Atlantic Coast of Europe, C. robusta co-occurs with C. intestinalis in Plymouth Harbor, England and Brittany, France (Caputi et al. 2007; Zhan et al. 2010; Nydam and Harrison 2011; Sato et al. 2012). Ciona robusta's distribution in this region is highly localized, and more sporadic, while the range of C. intestinalis is more continuous. In 2007, purebred individuals were found at 3 locations each in southwest England and Brittany, but by 2009 only hybrids were found, and at only two locations each (Nydam and Harrison 2011). Nydam and Harrison (2011) suggested that shipping or Pacific Oyster (Crassostrea gigas) introductions were possible vectors for these introductions.

'C. intestinalis' was reported from Durbin, South Africa on the Indian Ocean in 1955 (Millar 1955, cited by Monniot et al. 2001), from Saldanha Bay on the Atlantic side in 1962, and at many South African ports by 2001 (Monniot et al. 2001; Mead et al. 2011b; Rius et al. 2014). Populations from Cape Town have been identified as C. robusta (Zhan et al. 2010). In the Southwest Atlantic, 'C. intestinalis' was first collected in 1945 in Mar del Plata, Argentina (Orensanz et al. 2002) and was found in San Antonio Este and Puerto Madryn in 2005 (Schwindt et al. 2014). It was collected in Santos, Brazil by 1958 (Millar 1958), and has been found sporadically between Santos and Rio de Janeiro (de Oliveira Marins et al. 2009; da Rocha and Bonnet 2009). We presume that these records refer to C. robusta, but molecular confirmations are needed.

In Australia, the first record of 'C. intestinalis' is from Port Jackson, Sydney, New South Wales in 1878 (Kott 1990; Keough and Ross 1999). It was subsequently found at many ports around the southern coast of Australia, including: Fremantle and Albany in Western Australia (Hartmeyer and Michaelsen 1928, cited by Kott 1990); Port Adelaide, South Australia; Hobart, Tasmania (Kott 1952, cited by Kott 1990); and Port Philip Bay, New South Wales (in 1958, Millar 1966, cited by Keough and Ross 1999). Specimens from Port Lincoln, South Australia have been identified as C. robusta ('Species A.', Zhan et al. 2010). In New Zealand, 'Ciona intestinalis' was first reported in 1950 (Brewin 1950) in Lyttleton Harbour. It is known from the harbors of Lyttleton, Napier and Nelson (Cranfield et al. 1998; Inglis et al. 2006c; Inglis et al. 2006f). Specimens from Nelson were identified as C. robusta by molecular methods (Species A.', Smith et al. 2010).

On the other side of the Pacific, ‘C. intestinalis' was reported, very early, from the Straits of Magellan, Chile (Traustedt 1885, cited by Dybern 1965; Castilla et al. 2005). Experiments suggest that C. intestinalis is unlikely to become established in the Magellan region (Madariaga et al. 2014). However, since 2002, populations have become established in bays from the Peruvian border to central Chile (14-40°S, Castilla et al. 2005; Sanamyan and Schories 2005; Madariaga et al. 2014). Chilean populations are presumed to be C. robusta, but have not been identified by molecular methods.


Description

Ciona 'intestinalis' ws formerly considered to be widely distributed in the Atlantic, Mediterranean, and North and South Pacific (Van Name 1912; Van Name 1945; Dybern 1965; Carlton 1979; Hoshino and Nishikawa 1985; Nishikawa 1991). Recent morphological and genomic work has shown that ‘'Ciona intestinalis'’, which was described from Sweden by Linneaus in 1767, is a complex of species (Caputi et al. 2007; Brunetti et al. 2015; Pennati et al. 2015). Genomic studies revealed genetic differences between European populations, with Mediterranean populations showing strong affinities with US West Coast and most Asian populations, while diverging from Northern European and East Coast populations (Boffelli et al. 2004; Suzuki et al. 2005; Caputi et al. 2007; Nydam and Harrison 2007; Nydam and Harrison 2010). Caputi et al. (2007) identified the Mediterranean-Pacific form as 'Ciona intestinalis sp. A', and noted that it was more genetically homogeneous than the North Atlantic 'Ciona intestinalis sp. B', which was more geographically structured. Hybrids of the two species were asymmetrically infertile. C. intestinalis can be fertilized by C. robusta sperm, but the reverse cross had very low fertility (Caputi et al. 2007; Malfant et al. 2017). Hybrids are rare in the wild (Bouchemousse et al. 2016b; Malfant et al. 2017). Populations of the two species were found to overlap in Plymouth Harbour, England, and could be separated by morphology (tubercles on the tunic near the siphon, in species B) and coloration (Sato et al. 2012). These tubercles had been described previously in a Japanese form, given the name Ciona robusta (Hoshino and Tokioka 1967), but later synonymized with C. intestinalis (Hoshino and Nishikawa 1985). Brunetti et al. (2015) found that the tubercles could be detected over the whole tunic, in 'species A', using appropriate lighting, histology, and 3-D reconstruction, in combination with genetic information. They identified 'species A' as C. robusta. However pigmentation and tubercles alone were insufficient to separate the two species. Morphometric features of larvae are the most decisive morphological feature for separating the two species (Pennati et al. 2015).

Ciona robusta has a transparent or translucent tunic. Much of the tunic is soft, flexible, and gelatinous, except for the posterior end where it can be tough, mostly opaque, white or yellowish-white. The muscle bands and organs are often visible beneath the tunic. The body is white or off-white. The siphons are short and directed forward, with the oral siphon larger than the atrial siphon. The oral siphon has 8 lobes, while the atrial siphon has 6 lobes. Both siphons lack bright pigment, although a pale white or yellow tinge is sometimes visible. Tubercles on the tunic are usually most visible near the siphons, but are scattered over the surface, though lighting, histological sectioning, and 3-D imaging may be needed to see all of them. There are 5-7 conspicuous longitudinal muscle bands on each side that extend nearly the entire length of the body (Hoshino and Tokioka 1967; Sato et al. 2012; Brunetti et al. 2015). Ciona robusta can reach a length of 210 mm long, but a more typical maximum is 100-120 mm (Hoshino and Tokioka 1967; Hoshino and Nishikawa 1985, specimens from Naples).

Ciona robusta is very similar in appearance to C. savignyi, but there are a few notable morphological differences. Ciona robusta never has white pigmented flecks or spots in its body wall while C. savignyi always has these spots. The number of tentacles around the oral siphon is variable in both species but generally C. robusta has more (n>50) tentacles than C. savignyi (Hoshino and Nishikawa 1985). Ciona robusta has an endostylar appendage while C. savignyi does not (Hoshino and Nishikawa 1985). The pair of pharyngeo-epicardiac openings in C. robusta is usually very small and located near its base while in C. savignyi these openings are located close to the esophageal opening (Hoshino and Nishikawa 1985).

Sato et al. (2012) found C. robusta (at that time it was known as C. intestinalis species 'A') and C. intestinalis ('species B') living sympatrically in Plymouth Harbor, England, as indicated by genetic analysis. Ciona robusta specimens had little pigment on the margins of the oral siphons, while most C. intestinalis tunicates had strong yellow pigmentation on the margins. Most C. robusta had small tubercles on the tunic, while most C. intestinalis specimens lacked them. The two species also tended to differ in the color of papillae on the gonoducts, with more intense coloration in most C. intestinalis specimens. These differences were heritable in culture, and intermediate in hybrids (Sato et al. 2012). As larvae, C. robusta have a shorter pre-oral lobe, a shorter and wider body, and a long ocellus-tail distance, compared to C. intestinalis (Pennati et al. 2015). Additional sampling will be needed to determine whether these differences are consistent over regions and seasons (Pennati et al. 2015).


Taxonomy

Taxonomic Tree

Kingdom:   Animalia
Phylum:   Chordata
Subphylum:   Tunicata
Class:   Ascidiacea
Order:   Phlebobranchia
Family:   Cionidae
Genus:   Ciona
Species:   robusta

Synonyms

Ciona intestinalis species A (None, None)
Ascidia intestinalis ( Linnaeus, 1767)
Ascidia canina (Mueller, 1776)

Potentially Misidentified Species

Ciona intestinalis
Ciona intestinalis is native to the North Atlantic, and distinguishable from C. robusta by genetics, and to varying degrees by pigmentation, the presence of tubercles on the tunic, and larval morphology (Caputi et al. 2007; Nydam and Harrison 2007; Zhan et al. 2010; Sato et al. 2012; Brunetti et al. 2015; Pennati et al. 2015). It has been introduced to the Yellow and Bohai Seas (Zhan et al. 2010) and to Iceland (Svavarsson and Dungal 2008, cited by Thorarinsdottir et al. 2014).

Ciona savignyii
Ciona savignyii is a Northwest Pacific native, introduced to the West Coast (Lambert and Lambert 1998; Lambert 2003) and New Zealand (Smith et al. 2010).

Ciona Species C
Ciona Species C is an undescribed species identified by molecular means from the Mediterranean (Zhan et al. 2010).

Ciona Species D
Ciona Species D is an undescribed species identified by molecular means from the Black Sea (Zhan et al. 2010).

Ecology

General:

Life History – Ciona robusta is a vase-shaped, solitary tunicate, attached at its base to a substrate. It has two openings or siphons, an oral and an atrial siphon. Water is pumped in through the oral siphon, where phytoplankton and detritus is filtered by the gills and passed on mucus strings to the stomach and intestines. Waste is then expelled in the outgoing atrial water.

Solitary ascidians are hermaphroditic, meaning that both eggs and sperm are released to the atrial chamber. Eggs may be self-fertilized or fertilized by sperm from nearby animals, but many species have a partial block to self-fertilization. In C. robusta from the Tyrrhenian Sea, Italy, both self- and non-self-fertilization took place (Caputi et al. 2015). Depending on the species, eggs may be externally or internally fertilized. In external fertilizers, such as C. robusta, eggs and sperm are released through the atrial siphon into the surrounding water column where fertilization takes place. Fertilized eggs hatch into a tadpole larva with a muscular tail, notochord, eyespots, and a set of adhesive papillae. The lecithotrophic (non-feeding, yolk-dependent) larva swims briefly before settlement. Swimming periods are usually less than a day and some larvae settle immediately after release. Once settled, the tail is absorbed, the gill basket expands, and the tunicate begins to feed by filtering (Barnes 1983).

Ciona robusta is an abundant fouling organism on pilings, buoys, aquaculture facilities, and rocky shores (Haderlie et al. 1978; Hoshino and Nishikawa 1985; Castillo et al. 2005; Dumont et al. 2011). Ciona robusta appears to differ from its cryptic congener C. intestinalis in its temperature and salinity tolerance, with C. robusta associated with Mediterranean and subtropical climates and higher salinities, while C. intestinalis tolerates more boreal climates and extends into lower salinities, including the Baltic Sea and Norwegian estuaries (Dybern 1965; Marin et al. 1987; Madariaga et al. 2014). The lowest average winter temperature tolerated by C. robusta was ~3°C in the Lagoon of Venice (Dybern 1965), while the lowest salinity tolerated was 21-25 PSU (Marin et al. 1987; Madariaga et al. 2014). By contrast, C. intestinalis survived temperatures below 0°C and salinities as low as 9 PSU (Dybern 1965; Dybern 1967). Ciona robusta is frequently rare or absent in natural rocky habitats, but very abundant on artificial structures. In Chile, this was apparently the result of predation by fishes and crabs – C. robusta became abundant in rocky habitat when predators were excluded (Dumont et al. 2011).

Food:

Phytoplankton, Bacteria, detritus

Consumers:

fish, crabs

Trophic Status:

Suspension Feeder

SusFed

Habitats

General HabitatMarinas & DocksNone
General HabitatRockyNone
General HabitatOyster ReefNone
General HabitatCoarse Woody DebrisNone
General HabitatVessel HullNone
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Vertical HabitatEndobenthicNone


Tolerances and Life History Parameters

Minimum Temperature (ºC)3Field, Venice, average minimum winter temperature (Dybern 1965)
Maximum Temperature (ºC)30Experimental, 36% survival after 15 days, of animals from Venice Lagoon, acclimated at 19 C and 30 ppt (Marin et al. 1987)
Minimum Salinity (‰)21Experimental, adult animals from Venice Lagoon (Marin et al. 1987)
Maximum Salinity (‰)50Experimental, 48% survival after 15 days; animals from Venice Lagoon, acclimated at 19 C and 30 ppt (Marin et al. 1987)
Minimum Reproductive Temperature12Experimental, Venice Lagoon (Marin et al. 1987)
Maximum Reproductive Temperature28Experimental, Venice Lagoon (Marin et al. 1987)
Minimum Reproductive Salinity29Experimental, egg hatching, Venice Lagoon (Marin et al. 1987)
Maximum Reproductive Salinity50Experimental, egg hatching, Venice Lagoon (Marin et al. 1987)
Minimum Duration0.5Egg development time (28 C, 37 PSU, Marin et al. 1987)
Maximum Height (mm)210A specimen from Naples. 100-120 mm is a more typical maximum size (Hoshino and Nishikawa 1985).

General Impacts

Economic Impacts

Shipping and Industry - Ciona robusta and C. intestinalis are widely known as fouling organisms of ships, docks (Visscher 1927; Woods Hole Oceanographic Institution 1951; Millar 1971), aquaculture operations (Rocha et al. 2009), and laboratory seawater systems (Fofonoff, pers. obs.).

Fisheries - The most serious economic impacts of C. robusta have been on shellfish aquaculture in Spain, Chile, Japan, South Africa, and New Zealand (Castilla et al. 2005; Robinson et al. 2005; Rocha et al. 2009). These aquaculture industries are likely affected economically as well. Another negative potential impact of C. robusta and other tunicates is that when they foul aquaculture gear and boats, they can retain and transport viable cells and cysts of toxic phytoplankton (Rosa et al. 2013).

Ecological Impacts

Competition - Ciona robusta is a formidable competitor since it can grow quickly and replace other species in fouling communities, both in its native and introduced ranges (Millar 1971; Lambert and Lambert 2003). Studies in San Francisco Bay, CA have found that it can strongly compete with other native and introduced fouling organisms (Blum et al. 2007). In a similar experiment, near Cape Town, South Africa, removal of C. robusta had no effect on species richness, diversity, or species composition. Impacts of C. robusta can vary with environmental conditions or the composition of the community (Robinson et al. 2017). On settlement panels on the coast of Brittany, C. robusta did not appear to replace or displace C. intestinalis, but was more sensitive to environmental changes, favored by higher temperatures (Bouchemousse et al. 2016).  Diversity within fouling communities was negatively correlated with C. robusta abundance, and experimental removal of C. robusta resulted in increased diversity (Blum et al. 2007). Since C. robusta is a strong competitor, fouling of C. robusta on cultured mussels and/or oysters in Spain, South Africa, Chile, Hong Kong, Japan, and New Zealand (Rocha et al. 2009), is likely damaging to shellfish industries. However, effects on wild mussel and other shellfish populations are less clear.

Regional Impacts

P090San Francisco BayEcological ImpactCompetition
In San Francisco Bay, this tunicate appears to strongly compete with other fouling organisms, both native and introduced (Blum et al. 2007). Fouling community diversity was negatively correlated with C. robusta's abundance, and experimental removal of this tunicate resulted in increased diversity (Blum et al. 2007).
P090San Francisco BayEcological ImpactHabitat Change
The tunics of C. robusta provided a poor substrate for settlement of other organisms when this organism dominated fouling plates (Blum et al. 2007).
NEP-VNorthern California to Mid Channel IslandsEcological ImpactCompetition
In San Francisco Bay, this tunicate appears to strongly compete with other fouling organisms, both native and introduced (Blum et al. 2007). Fouling community diversity was negatively correlated with C. robusta abundance, and experimental removal of this tunicate resulted in increased diversity (Blum et al. 2007).
NEP-VNorthern California to Mid Channel IslandsEcological ImpactHabitat Change
The tunics of C. intestinalis provided a poor substrate for settlement of other organisms when this organism dominated fouling plates (Blum et al. 2007).
P064_CDA_P064 (Ventura)Ecological ImpactCompetition
Ciona robusta and other introduced ascidians have replaced the native species Pyura haustor and Ascidia ceratodes in southern California harbors (Lambert and Lambert 1998).
NEP-VIPt. Conception to Southern Baja CaliforniaEcological ImpactCompetition
Ciona robusta formed large monospecific patches in San Diego Bay, Mission Bay, Newport Bay, Los Angeles-Long Beach Harbors, King Harbor and Santa Barbara Harbor, indicating strong competition (Lambert and Lambert 2003). It and other introduced ascidians have replaced the native species Pyura haustor and Ascidia ceratodes from southern California harbors (Lambert and Lambert 1998).
P062_CDA_P062 (Calleguas)Ecological ImpactCompetition
Ciona robusta and other introduced ascidians have replaced the native species Pyura haustor and Ascidia ceratodes in southern California harbors (Lambert and Lambert 1998).
P065_CDA_P065 (Santa Barbara Channel)Ecological ImpactCompetition
Ciona robusta formed large monospecific patches in Santa Barbara Harbor, indicating strong competition (Lambert and Lambert 2003). It and other introduced ascidians have replaced the native species Pyura haustor and Ascidia ceratodes from southern California harbors (Lambert and Lambert 1998).
P060Santa Monica BayEcological ImpactCompetition
Ciona robusta formed large monospecific patches in King Harbor, indicating strong competition (Lambert and Lambert 2003).
NWP-2NoneEcological ImpactCompetition
Fouling of cultured shellfish by C. robusta has been reported in Hong Kong (Huang 2003, cited by da Rocha et al. 2009).
NWP-2NoneEconomic ImpactFisheries
Fouling of cultured shellfish by C. robusta has been reported in Hong Kong (Huang 2003, cited by da Rocha et al. 2009).
P050San Pedro BayEcological ImpactCompetition
Ciona robusta formed large monospecific patches in Los Angeles-Long Beach Harbors, indicating strong competition (Lambert and Lambert 2003). It and other introduced ascidians have replaced the native species Pyura haustor and Ascidia ceratodes in southern California harbors (Lambert and Lambert 1998).
P040Newport BayEcological ImpactCompetition
Ciona robusta formed large monospecific patches in Newport Bay, indicating strong competition (Lambert and Lambert 2003). It and other introduced ascidians have replaced the native species Pyura haustor and Ascidia ceratodes in southern California harbors (Lambert and Lambert 1998).
P027_CDA_P027 (Aliso-San Onofre)Ecological ImpactCompetition
Ciona robusta and other introduced ascidians have replaced the native species Pyura haustor and Ascidia ceratodes in southern California harbors (Lambert and Lambert 1998).
P030Mission BayEcological ImpactCompetition
Ciona robusta formed large monospecific patches in Mission Bay, indicating strong competition (Lambert and Lambert 2003). It and other introduced ascidians have replaced the native species Pyura haustor and Ascidia ceratodes in southern California harbors (Lambert and Lambert 1998).
P020San Diego BayEcological ImpactCompetition
Ciona robusta formed large monospecific patches in San Diego Bay, indicating strong competition (Lambert and Lambert 2003). It and other introduced ascidians have replaced the native species Pyura haustor and Ascidia ceratodes in southern California harbors (Lambert and Lambert 1998).
SEP-CNoneEconomic ImpactFisheries
Ciona robusta has become an abundant fouling organism on cultured scallops in aquaculture operations off Chile (Castillo et al. 2005; Dumont et al. 2011).
NWP-3bNoneEconomic ImpactFisheries
Fouling of cultured shellfish by C. robusta has been reported in Japan (Arakawa, cited by da Rocha et al. 2009).
NWP-3bNoneEcological ImpactCompetition
Fouling of cultured shellfish by C. robusta has been reported in Japan (Arakawa, cited by da Rocha et al. 2009).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
NEP-III Alaskan panhandle to N. of Puget Sound 1912 Def Unk
NEP-IV Puget Sound to Northern California 2000 Def Unk
NEP-V Northern California to Mid Channel Islands 1932 Def Estab
P112 _CDA_P112 (Bodega Bay) 2004 Def Estab
P110 Tomales Bay 2001 Def Estab
P090 San Francisco Bay 1932 Def Estab
P086 _CDA_P086 (San Francisco Coastal South) 2007 Def Estab
P080 Monterey Bay 1974 Def Estab
P070 Morro Bay 1968 Def Estab
NEP-VI Pt. Conception to Southern Baja California 1897 Def Estab
P065 _CDA_P065 (Santa Barbara Channel) 1970 Def Estab
P064 _CDA_P064 (Ventura) 1994 Def Estab
P062 _CDA_P062 (Calleguas) 1994 Def Estab
P060 Santa Monica Bay 1970 Def Estab
NEA-III None 2003 Def Estab
MED-VII None 1875 Def Estab
MED-III None 1882 Def Estab
MED-III None 0 Def Estab
MED-IV None 0 Def Estab
MED-V None 1816 Def Estab
NEA-IV None 0 Def Estab
MED-II None 1884 Def Estab
NWP-3b None 0 Native Estab
NWP-4b None 1967 Native Estab
NWP-3a None 0 Native Estab
MED-VI None 0 Def Estab
NWP-2 None 1975 Crypto Estab
NWP-4a None 0 Native Estab
P040 Newport Bay 1939 Def Estab
WA-IV None 1962 Def Estab
WA-V None 1955 Def Estab
AUS-VII None 1952 Def Estab
NEA-V None 2007 Def Unk
AUS-VIII None 1958 Def Estab
AUS-X None 1878 Def Estab
AUS-IX None 1952 Def Estab
AUS-V None 1928 Def Estab
AUS-IV None 1928 Def Estab
NZ-IV None 1950 Def Estab
P050 San Pedro Bay 1955 Def Estab
P027 _CDA_P027 (Aliso-San Onofre) 1996 Def Estab
P023 _CDA_P023 (San Louis Rey-Escondido) 2001 Def Estab
P030 Mission Bay 1964 Def Estab
P020 San Diego Bay 1897 Def Estab
SP-XXI None 1933 Def Estab
WA-I None 1949 Def Unk
WA-VI None 1994 Def Unk
SA-II None 1914 Def Estab
SA-I None 1945 Def Estab
SEP-C None 2002 Def Estab
SEP-A' None 1885 Def Unk
RS-3 None 2003 Def Estab
MED-I None 0 Def Estab
NEA-II None 2012 Def Estab
P130 Humboldt Bay 0 Def Failed
RS-1 None 2015 Def Estab
EAS-I None 1985 Crypto Unk
AUS-I None 2001 Def Estab
EAS-III None 1980 Crypto Estab
AR-IV None 2018 Def Unk

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude
767368 Ruiz et al., 2015 2012 2012-08-22 Tomales-Marshall, Bodega Bay, California, USA Def 38.1514 -122.8888
767379 Ruiz et al., 2015 2012 2012-08-21 Tomales-Nick's Cove, Bodega Bay, California, USA Def 38.1980 -122.9222
767399 Ruiz et al., 2015 2012 2012-08-16 Tomales-SNPS, Bodega Bay, California, USA Def 38.1359 -122.8719
767411 Ruiz et al., 2015 2012 2012-08-17 Tomales- Shell Beach, Bodega Bay, California, USA Def 38.1163 -122.8713
767443 Ruiz et al., 2015 2013 2013-07-23 Marina Village, Mission Bay, CA, California, USA Def 32.7605 -117.2364
767460 Ruiz et al., 2015 2013 2013-07-29 Mission Bay Yacht Club, Mission Bay, CA, California, USA Def 32.7778 -117.2485
767480 Ruiz et al., 2015 2013 2013-08-04 Bahia Resort Marina, Mission Bay, CA, California, USA Def 32.7731 -117.2478
767493 Ruiz et al., 2015 2013 2013-07-31 Campland on the Bay, Mission Bay, CA, California, USA Def 32.7936 -117.2234
767511 Ruiz et al., 2015 2013 2013-08-01 Hyatt Resort Marina, Mission Bay, CA, California, USA Def 32.7634 -117.2397
767526 Ruiz et al., 2015 2013 2013-08-03 Mission Bay Sport Center, Mission Bay, CA, California, USA Def 32.7857 -117.2495
767540 Ruiz et al., 2015 2013 2013-07-30 Hilton Resort Docks, Mission Bay, CA, California, USA Def 32.7791 -117.2128
767555 Ruiz et al., 2015 2013 2013-08-02 The Dana Marina, Mission Bay, CA, California, USA Def 32.7671 -117.2363
767566 Ruiz et al., 2015 2013 2013-08-05 Paradise Point Resort, Mission Bay, CA, California, USA Def 32.7730 -117.2406
767668 Ruiz et al., 2015 2013 2013-07-16 Naval Base Point Loma, San Diego Bay, CA, California, USA Def 32.6886 -117.2343
767680 Ruiz et al., 2015 2013 2013-07-17 Naval Station San Diego, San Diego Bay, CA, California, USA Def 32.6867 -117.1333
767694 Ruiz et al., 2015 2013 2013-07-24 NAB ACU-1 Docks, San Diego Bay, CA, California, USA Def 32.6786 -117.1615
767707 Ruiz et al., 2015 2013 2013-07-25 Navy Ammo Dock, Pier Bravo, San Diego Bay, CA, California, USA Def 32.6939 -117.2276
767718 Ruiz et al., 2015 2013 2013-07-21 Cabrillo Isle Marina, San Diego Bay, CA, California, USA Def 32.7272 -117.1995
767746 Ruiz et al., 2015 2013 2013-07-18 NAB Fiddlers Cove, San Diego Bay, CA, California, USA Def 32.6524 -117.1486
767763 Ruiz et al., 2015 2013 2013-07-26 Pier 32 Marina, San Diego Bay, CA, California, USA Def 32.6516 -117.1077
767773 Ruiz et al., 2015 2013 2013-07-20 Chula Vista Marina, San Diego Bay, CA, California, USA Def 32.6252 -117.1036
767786 Ruiz et al., 2015 2013 2013-07-28 Marriott Marquis and Marina, San Diego Bay, CA, California, USA Def 32.7059 -117.1655
767922 Ruiz et al., 2015 2011 2011-09-20 Jack London Square Marina, San Francisco Bay, CA, California, USA Def 37.7947 -122.2822
767988 Ruiz et al., 2015 2012 2012-08-24 Richmond Marina Bay Yacht Harbor, San Francisco Bay, CA, California, USA Def 37.9134 -122.3523
768064 Ruiz et al., 2015 2012 2012-09-11 Ballena Isle Marina, San Francisco Bay, CA, California, USA Def 37.7676 -122.2869
768087 Ruiz et al., 2015 2012 2012-08-30 Oyster Point Marina, San Francisco Bay, CA, California, USA Def 37.6633 -122.3817
768111 Ruiz et al., 2015 2012 2012-08-29 Coyote Point Marina, San Francisco Bay, CA, California, USA Def 37.5877 -122.3174
768133 Ruiz et al., 2015 2012 2012-09-04 Redwood City Marina, San Francisco Bay, CA, California, USA Def 37.5023 -122.2130
768177 Ruiz et al., 2015 2012 2012-09-05 Port of Oakland, San Francisco Bay, CA, California, USA Def 37.7987 -122.3228
768197 Ruiz et al., 2015 2012 2012-09-07 Jack London Square Marina, San Francisco Bay, CA, California, USA Def 37.7940 -122.2787
768253 Ruiz et al., 2015 2012 2012-09-12 Emeryville, San Francisco Bay, CA, California, USA Def 37.8396 -122.3133
768279 Ruiz et al., 2015 2013 2013-08-15 Ballena Isle Marina, San Francisco Bay, CA, California, USA Def 37.7656 -122.2858
768299 Ruiz et al., 2015 2013 2013-08-20 Coyote Point Marina, San Francisco Bay, CA, California, USA Def 37.5877 -122.3163
768318 Ruiz et al., 2015 2013 2013-08-22 Jack London Square Marina, San Francisco Bay, CA, California, USA Def 37.7926 -122.2746
768359 Ruiz et al., 2015 2013 2013-08-13 Oyster Point Marina, San Francisco Bay, CA, California, USA Def 37.6639 -122.3821
768383 Ruiz et al., 2015 2013 2013-08-14 Redwood City Marina, San Francisco Bay, CA, California, USA Def 37.5024 -122.2134
768403 Ruiz et al., 2015 2013 2013-08-19 Richmond Marina Bay Yacht Harbor, San Francisco Bay, CA, California, USA Def 37.9138 -122.3522
768420 Ruiz et al., 2015 2013 2013-08-12 San Francisco Marina, San Francisco Bay, CA, California, USA Def 37.8078 -122.4354
768451 Ruiz et al., 2015 2013 2013-08-16 Sausalito Marine Harbor, San Francisco Bay, CA, California, USA Def 37.8611 -122.4851

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