Invasion History

First Non-native North American Tidal Record: 1985
First Non-native West Coast Tidal Record: 1985
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Ciona savignyi appears to be native to Japan and possibly northern Asia. In Japan, it can be found from Mutsu Bay (north end of Honshu) to the Seto Inland Sea (south end of Honshu), both on the Pacific and Sea of Japan coasts (Hoshino and Nishikawa 1980; Nishikawa 1991). In 2004, it was first collected as an introduced species in the most northern reaches of the Sea of Japan, in Peter the Great Bay, Russia (Zvyagintsev et al. 2007). In the northeast Pacific, there are two puzzling records from southeastern Alaska (Inside Passage: Loring, in Behm Canal) and northern British Columbia (Stuart Island, in Queen Charlotte Strait) (AK in 1903, USNM 5633, U.S. National Museum of Natural History 2003; BC in 1937, Lambert 2003). These could represent a cryptic species, a very early introduction, or a relict population. There are also disjunct records from Argentina (Hoshino and Nishikawa 1985) and Spain (Perez et al. 1957) which for the purposes of this database, we consider unverified. However, C. savignyi has recently invaded shallow coastal waters of central and southern California and Puget Sound (Cohen and Carlton 1995; Lambert and Lambert 1998; Lambert 2003; Cohen et al. 2005; Blum et al. 2007).

North American Invasion History:

Invasion History on the West Coast:

The first record of Ciona savignyi in continental US waters was in 1985 in Long Beach Harbor, southern CA (Lambert and Lambert 1998). In 1993, it was collected in central California, San Francisco Bay (Cohen and Carlton 1995). By 1994 the southern California population ranged from San Diego Bay to Santa Barbara Harbor, CA (Lambert and Lambert 1998; Lambert and Lambert 2003). The central California population soon included specimens collected in 1998 Elkhorn Slough surveys (Wasson et al. 2001) and in 2003 Monterey and Moss Landing Harbors samples (deRivera et al. 2005). As of 2005, C. savignyi has been collected in the central and southern sections of San Francisco Bay, but not the more northern San Pablo Bay (Cohen et al. 2005; Ruiz et al. unpublished data). North of San Francisco Bay, C. savignyi has been found in samples collected from Tomales Bay (in 2001, Fairey et al. 2002), Bodega Harbor (deRivera et al. 2005), and Humboldt Bay, CA (in 2001, Fairey et al. 2002; Ruiz et al. unpublished data).

In Washington, C. savignyi has spread throughout Puget Sound. It was first discovered in 1998 in the Des Moines Marina near Seattle and by 1999 it had spread north to the Brownsville and Edmonds Marinas. In 2001, it was found near the Tacoma Yacht Club in Tacoma, WA (Lambert 2003). Subsequently, scuba divers discovered extensive populations in several other parts of Puget Sound, including Hood Canal in the western portion of Puget sound (in 2005, USGS Nonindigenous Aquatic Species Program 2003-2012) and in more northern reaches of the San Juan Islands (USGS Nonindigenous Aquatic Species Program 2003-2012).


Description

Ciona savignyi is a solitary tunicate with a smooth, elongated, cylindrical or vase-shaped body which can reach a length of 150 mm long. It is widest near the permanently attached posterior end and tapers toward the anterior end, compressed laterally. The tunic is transparent, translucent, and white or yellowish-green in color. Much of the tunic is soft, flexible and gelatinous. The muscle bands and organs are often visible beneath the tunic surface. Its siphons are on short, forwardly directed (not divergent) and the oral siphon is larger than the atrial siphon. The oral siphon has 8 lobes, each with a yellow margin containing 8 reddish-orange spots. The atrial siphon has 6 lobes, each with a yellow margin containing 6 reddish-orange spots. There are 5-7 conspicuous longitudinal muscle bands on each side of the body that extend nearly the entire length of the body (Van Name 1945; Kott 1985; Lambert and Lambert 1998).

Ciona savignyi is very similar in appearance to C. intestinalis, but there are a few notable morphological differences. Ciona savignyi always has white pigmented flecks, or spots, in its body wall while C. intestinalis lacks these. Additionally, C. savignyi has orange pigmentation around the siphon while C. intestinalis has yellow pigmentation (Smith et al. 2010). The number of tentacles around the oral siphon is variable in both species, but generally C. savignyi have fewer (n<50) tentacles than C. intestinalis (Hoshino and Nishikawa 1985). Ciona savignyi does not have an endostylar appendage while C. intestinalis has endostyles. Additionally, the pharyngeo-epicardiac openings in C. savignyi are located close to the oesophageal opening while in C. intestinalis these openings are usually very small and located near its base (Hoshino and Nishikawa 1985). Lastly, the color of the enlarged end of the vas deferens is always white in C. savignyi and red in the West Coast C. intestinalis (Lambert and Lambert 1998).


Taxonomy

Taxonomic Tree

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

Synonyms

Ciona aspera (Herdman, 1886)

Potentially Misidentified Species

Ciona intestinalis
Ritter 1913, mis-identification of specimen from Loring, Alaska (Lambert 2003)

Ciona robusta
None

Ecology

General:

Life History- A solitary tunicate is ovoid, elongate or vase-like in shape, with two openings or siphons. Most solitary tunicates attach to substrates by their side or base, but some attach with a conspicuous stalk. They are sessile filter feeders with two 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. Depending on species, eggs may be externally or internally fertilized. In external fertilizers, eggs and sperm are released through the atrial siphon into the surrounding water column were fertilization takes place. In internal fertilizers, eggs are brooded and fertilized within the atrial chamber and then released into the water column upon hatching. 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, but the larval period can be longer at lower temperatures. Once settled, the tail is absorbed, the gill basket expands, and the tunicate begins to feed by filtering (Barnes 1983).

Food:

Phytoplankton

Trophic Status:

Suspension Feeder

SusFed

Habitats

General HabitatMarinas & DocksNone
General HabitatRockyNone
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Vertical HabitatEpibenthicNone

Life History


Tolerances and Life History Parameters

Maximum Temperature (ºC)26.7Field, US East & West Coast marinas (Lord et al. 2015)
Maximum Length (mm)94Hoshino and Nishikawa 1985
Broad Temperature RangeNoneCold temperate-Warm temperate
Broad Salinity RangeNonePolyhaline-Euhaline

General Impacts

Economic Impacts

Shipping and Industry: Ciona savignyi is now an abundant component of the fouling community in southern California and Puget Sound (Lambert and Lambert 2003). It is likely that fouling by C. savignyi affects shipping and harbor uses, but no impacts have been reported.


Ecological Impacts

Competition: Currently, little is known about species competition with C. savignyi despite the fact that it is an abundant component of the fouling community in southern California and Puget Sound (Lambert and Lambert 2003). In southern California, it has been speculated that species competition is possible with C. intestinalis. However, die-offs of both species, due to environmental changes, make it difficult to determine the extent of competition. Lambert and Lambert (2003) state that 'Perhaps C. savignyi would eventually replace C. intestinalis were it not that the frequently changing habitat apparently tends to stabilize their co-occurrence in nearly equal numbers.'


Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
NEP-VI Pt. Conception to Southern Baja California 1985 Def Estab
NEP-V Northern California to Mid Channel Islands 1993 Def Estab
NEP-III Alaskan panhandle to N. of Puget Sound 1903 Crypto Unk
NWP-4b None 0 Native Estab
NWP-3b None 1882 Native Estab
NWP-4a None 0 Native Estab
NEP-IV Puget Sound to Northern California 2001 Def Estab
AUS-V None 2002 Def Estab
P050 San Pedro Bay 1985 Def Estab
P130 Humboldt Bay 2001 Def Estab
P020 San Diego Bay 1994 Def Estab
P030 Mission Bay 1994 Def Estab
P023 _CDA_P023 (San Louis Rey-Escondido) 1998 Def Estab
P040 Newport Bay 1994 Def Estab
P060 Santa Monica Bay 1995 Def Estab
P062 _CDA_P062 (Calleguas) 1994 Def Estab
P064 _CDA_P064 (Ventura) 1996 Def Estab
P065 _CDA_P065 (Santa Barbara Channel) 1994 Def Estab
P080 Monterey Bay 2003 Def Estab
P090 San Francisco Bay 1993 Def Estab
P110 Tomales Bay 2001 Def Estab
P290 Puget Sound 1998 Def Estab
P292 _CDA_P292 (San Juan Islands) 2008 Def Estab
P112 _CDA_P112 (Bodega Bay) 2004 Def Estab
NZ-IV None 2010 Def Estab
NWP-3a None 0 Native Estab
P027 _CDA_P027 (Aliso-San Onofre) 2011 Def Estab
SA-I None 1962 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude
767444 Ruiz et al., 2015 2013 2013-07-23 Marina Village, Mission Bay, CA, California, USA Def 32.7605 -117.2364
767494 Ruiz et al., 2015 2013 2013-07-31 Campland on the Bay, Mission Bay, CA, California, USA Def 32.7936 -117.2234
767512 Ruiz et al., 2015 2013 2013-08-01 Hyatt Resort Marina, Mission Bay, CA, California, USA Def 32.7634 -117.2397
767556 Ruiz et al., 2015 2013 2013-08-02 The Dana Marina, Mission Bay, CA, California, USA Def 32.7671 -117.2363
767681 Ruiz et al., 2015 2013 2013-07-17 Naval Station San Diego, San Diego Bay, CA, California, USA Def 32.6867 -117.1333
767695 Ruiz et al., 2015 2013 2013-07-24 NAB ACU-1 Docks, San Diego Bay, CA, California, USA Def 32.6786 -117.1615
767719 Ruiz et al., 2015 2013 2013-07-21 Cabrillo Isle Marina, San Diego Bay, CA, California, USA Def 32.7272 -117.1995
767732 Ruiz et al., 2015 2013 2013-07-22 Coronado Cays Marina, San Diego Bay, CA, California, USA Def 32.6257 -117.1309
767747 Ruiz et al., 2015 2013 2013-07-18 NAB Fiddlers Cove, San Diego Bay, CA, California, USA Def 32.6524 -117.1486
767764 Ruiz et al., 2015 2013 2013-07-26 Pier 32 Marina, San Diego Bay, CA, California, USA Def 32.6516 -117.1077
767787 Ruiz et al., 2015 2013 2013-07-28 Marriott Marquis and Marina, San Diego Bay, CA, California, USA Def 32.7059 -117.1655
767804 Ruiz et al., 2015 2011 2011-09-15 Richmond Marina Bay Yacht Harbor, San Francisco Bay, CA, California, USA Def 37.9117 -122.3494
767858 Ruiz et al., 2015 2011 2011-09-13 Oyster Point Marina, San Francisco Bay, CA, California, USA Def 37.6725 -122.3864
767892 Ruiz et al., 2015 2011 2012-09-19 Sausalito Marine Harbor, San Francisco Bay, CA, California, USA Def 37.8609 -122.4853
767909 Ruiz et al., 2015 2011 2011-09-21 South Beach Harbor, San Francisco Bay, CA, California, USA Def 37.7797 -122.3871
767923 Ruiz et al., 2015 2011 2011-09-20 Jack London Square Marina, San Francisco Bay, CA, California, USA Def 37.7947 -122.2822
767934 Ruiz et al., 2015 2011 2011-09-22 Ballena Isle Marina, San Francisco Bay, CA, California, USA Def 37.7676 -122.2869
767953 Ruiz et al., 2015 2011 2011-09-12 Paradise Cay Yacht Harbor, San Francisco Bay, CA, California, USA Def 37.9156 -122.4769
767969 Ruiz et al., 2015 2011 2011-09-12 Corinthian Yacht Club, San Francisco Bay, CA, California, USA Def 37.8103 -122.3228
767989 Ruiz et al., 2015 2012 2012-08-24 Richmond Marina Bay Yacht Harbor, San Francisco Bay, CA, California, USA Def 37.9134 -122.3523
768008 Ruiz et al., 2015 2012 2012-08-23 Sausalito Marine Harbor, San Francisco Bay, CA, California, USA Def 37.8609 -122.4853
768023 Ruiz et al., 2015 2012 2012-08-28 San Francisco Marina, San Francisco Bay, CA, California, USA Def 37.8071 -122.4341
768042 Ruiz et al., 2015 2012 2012-08-27 Port of San Francisco Pier 31, San Francisco Bay, CA, California, USA Def 37.8078 -122.4060
768065 Ruiz et al., 2015 2012 2012-09-11 Ballena Isle Marina, San Francisco Bay, CA, California, USA Def 37.7676 -122.2869
768088 Ruiz et al., 2015 2012 2012-08-30 Oyster Point Marina, San Francisco Bay, CA, California, USA Def 37.6633 -122.3817
768112 Ruiz et al., 2015 2012 2012-08-29 Coyote Point Marina, San Francisco Bay, CA, California, USA Def 37.5877 -122.3174
768134 Ruiz et al., 2015 2012 2012-09-04 Redwood City Marina, San Francisco Bay, CA, California, USA Def 37.5023 -122.2130
768178 Ruiz et al., 2015 2012 2012-09-05 Port of Oakland, San Francisco Bay, CA, California, USA Def 37.7987 -122.3228
768198 Ruiz et al., 2015 2012 2012-09-07 Jack London Square Marina, San Francisco Bay, CA, California, USA Def 37.7940 -122.2787
768254 Ruiz et al., 2015 2012 2012-09-12 Emeryville, San Francisco Bay, CA, California, USA Def 37.8396 -122.3133
768280 Ruiz et al., 2015 2013 2013-08-15 Ballena Isle Marina, San Francisco Bay, CA, California, USA Def 37.7656 -122.2858
768300 Ruiz et al., 2015 2013 2013-08-20 Coyote Point Marina, San Francisco Bay, CA, California, USA Def 37.5877 -122.3163
768319 Ruiz et al., 2015 2013 2013-08-22 Jack London Square Marina, San Francisco Bay, CA, California, USA Def 37.7926 -122.2746
768341 Ruiz et al., 2015 2013 2013-08-23 Loch Lomond Marina, San Francisco Bay, CA, California, USA Def 37.9723 -122.4829
768360 Ruiz et al., 2015 2013 2013-08-13 Oyster Point Marina, San Francisco Bay, CA, California, USA Def 37.6639 -122.3821
768384 Ruiz et al., 2015 2013 2013-08-14 Redwood City Marina, San Francisco Bay, CA, California, USA Def 37.5024 -122.2134
768404 Ruiz et al., 2015 2013 2013-08-19 Richmond Marina Bay Yacht Harbor, San Francisco Bay, CA, California, USA Def 37.9138 -122.3522

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