Ascidia zara

Invasion History

First Non-native North American Tidal Record: 0
First Non-native West Coast Tidal Record: 0
First Non-native East/Gulf Coast Tidal Record:

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General Invasion History:

Ascidia zara is native to the Northwest Pacific, ranging from Hokkaido, Japan (Nishikawa 1991) to the southern tip of Korea (Cheju Island; Rho et al. 2000). On the Pacific coast of North America, it has been collected in California and Bahia San Quintin, Mexico. It was first recognized in southern California in 1996; however, a preserved specimen from Los Angeles-Long Beach Harbor in 1984 was identified as A. zara (Lambert and Lambert 1998). This suggests that A. zara arrived prior to 1996, but went unnoticed because of its similarity to the native tunicate A. ceratodes. 

North American Invasion History:

Invasion History on the West Coast:

Ascidia zara was first recognized in southern California in 1996; however, a preserved specimen from Los Angeles-Long Beach Harbor in 1984 was identified as A. zara (Lambert and Lambert 1998). This suggests that A. zara arrived prior to 1996, but went unnoticed because of its similarity to the native tunicate A. ceratodes. It was collected in San Francisco Bay in 2000 (Ruiz et al. unpublished) and Elkhorn Slough and Bodega Harbor in 2001 and 2003 (Fairey et al. 2002; de Rivera et al. 2005). It is now widespread in San Francisco Bay (Cohen et al. 2005; Ruiz et al., unpublished data). In sampling throughout Southern California, Ascidia zara was abundant and widespread from 1995 to 2000 (Lambert and Lambert 1998; Lambert and Lambert 2003), but in 2011, was scarce. The native Ascidia ceratodes, which had become rare, was again common (Gretchen Lambert 2012, personal communication).

Invasion History Elsewhere in the World:

In 2005, Ascidia zara was collected in Bahia San Quintin, Mexico (Rodriguez and Ibarra-Obando 2008), but may have been overlooked in previous surveys there.

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Description

Ascidia zara is a solitary tunicate with an oval, flattened body. Its tunic is thin, translucent, and tears easily (Gretchen Lambert, personal communication). The tunic is covered with papillae, 100-500 µm in length, and variable in distribution and number. Both siphons are usually within the anterior third of the body and this species has around 30 large oral tentacles (Abbott et al., in Carlton 2007). Adults grow up to 57 mm long (Nishikawa 1991) and produce eggs that are brick red in color (Lambert and Lambert 1998).

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Taxonomy

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

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Habitats

General Habitat	Rocky	None
General Habitat	Marinas & Docks	None
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Tidal Range	Low Intertidal	None
Vertical Habitat	Epibenthic	None

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Tolerances and Life History Parameters

Minimum Salinity (‰)	20	Experimental, Chang 2009
Maximum Length (mm)	57	Nishikawa 1991
Broad Temperature Range	None	Warm temperate-Tropical
Broad Salinity Range	None	Polyhaline-Euhaline

General Impacts

Ascidia zara is a common component of fouling communities on the California coast. Its range spans from Bahia San Quintin, Baja California, Mexico (Rodriguez and Ibarra-Obando 2008) to San Francisco Bay (Lambert and Lambert 1998; Lambert and Lambert 2003). Records from 1917 indicate that the most abundant native tunicates in Southern California were Ascidia ceratodes and Pyura haustor (Ritter & Forsyth 1917, cited by Lambert and Lambert 1998). During sampling in this area in 1995-2000 it appeared that A. ceratodes was rare having been replaced by A. zara (Lambert and Lambert 2003). However, sampling in southern California during 2011 showed that A. zara was scarce, and A. ceratodes was again abundant (Gretchen Lambert 2012, personal communication).

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Regional Impacts

NEP-VI	Pt. Conception to Southern Baja California		Ecological Impact	Competition
Ascidia zara has largely replaced the native Ascidia ceratodes in Ventura Harbor (Lambert and Lambert 2003). Ritter & Forsyth (1917) reported that Ascidia ceratodes and Pyura haustor, both native, were the most numerous solitary ascidians in South California in 1917. In 1995-2000, A. ceratodes was rare having been replaced by A. zara. In 2011 sampling, A. zara had become scarce, and A. ceratodes was again abundant (Gretchen Lambert 2012, personal communication).
P020	San Diego Bay		Ecological Impact	Competition
Ascidia zara has largely replaced the native Ascidia ceratodes in San Diego Bay (Lambert and Lambert 2003;). Ritter & Forsyth (1917) reported that Ascidia ceratodes and Pyura haustor, both native, were the most numerous solitary ascidians in South California in 1917. In 1995-2000, A. ceratodes was rare having been replaced by A. zara.
P050	San Pedro Bay		Ecological Impact	Competition
Ascidia zara has largely replaced the native Ascidia ceratodes in San Diego Bay (Lambert and Lambert 2003;). Ritter & Forsyth (1917) reported that Ascidia ceratodes and Pyura haustor, both native, were the most numerous solitary ascidians in South California in 1917. In 1995-2000, A. ceratodes was rare having been replaced by A. zara.
P064	_CDA_P064 (Ventura)		Ecological Impact	Competition
Ascidia zara has largely replaced the native Ascidia ceratodes in San Diego Bay (Lambert and Lambert 2003;). Ritter & Forsyth (1917) reported that Ascidia ceratodes and Pyura haustor, both native, were the most numerous solitary ascidians in South California in 1917. In 1995-2000, A. ceratodes was rare having been replaced by A. zara.
CA	California		Ecological Impact	Competition
Ascidia zara has largely replaced the native Ascidia ceratodes in San Diego Bay (Lambert and Lambert 2003;). Ritter & Forsyth (1917) reported that Ascidia ceratodes and Pyura haustor, both native, were the most numerous solitary ascidians in South California in 1917. In 1995-2000, A. ceratodes was rare having been replaced by A. zara., Ascidia zara has largely replaced the native Ascidia ceratodes in San Diego Bay (Lambert and Lambert 2003;). Ritter & Forsyth (1917) reported that Ascidia ceratodes and Pyura haustor, both native, were the most numerous solitary ascidians in South California in 1917. In 1995-2000, A. ceratodes was rare having been replaced by A. zara., Ascidia zara has largely replaced the native Ascidia ceratodes in San Diego Bay (Lambert and Lambert 2003;). Ritter & Forsyth (1917) reported that Ascidia ceratodes and Pyura haustor, both native, were the most numerous solitary ascidians in South California in 1917. In 1995-2000, A. ceratodes was rare having been replaced by A. zara.

References

Abbott, Donald P.; Lambert, Charles C.; Lambert, Gretchen; Newberry, A. Todd (2007) The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon (4th Edtion), University of California Press, Berkeley, CA. Pp. 949-964

Barnes, Robert D. (1983) Invertebrate Zoology, Saunders, Philadelphia. Pp. 883

Beshai, Ryan A.; Truong, Danny A.; Henry, Amy K. Sorte, Cascade J. B. (2022) Biotic resistance or invasional meltdown? Diversity reduces invasibility but not exotic dominance in southern California epibenthic communities, Biological Invasions 25(2): 533-549
https://doi.org/10.1007/s10530-022-02932-1

California Department of Fish and Wildlife (2014) Introduced Aquatic Species in California Bays and Harbors, 2011 Survey, California Department of Fish and Wildlife, Sacramento CA. Pp. 1-36

Carlton, James T. (Ed.) (2007) The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon Fourth Edition, Completely Revised and Expanded, University of California Press, Berkeley. Pp. <missing location>

Chang, Andrew Louis (2009) <missing title>, University of California at Davis, Davis CA. Pp. <missing location>

Cohen, Andrew N. and 10 authors (2005) <missing title>, San Francisco Estuary Institute, Oakland CA. Pp. <missing location>

Cohen, Andrew N. and 12 authors (2002) Project report for the Southern California exotics expedition 2000: a rapid assessment survey of exotic species in sheltered coastal waters., In: (Eds.) . , Sacramento CA. Pp. 1-23

Cohen, Andrew N.; Carlton, James T. (1995) Nonindigenous aquatic species in a United States estuary: a case study of the biological invasions of the San Francisco Bay and Delta, U.S. Fish and Wildlife Service and National Sea Grant College Program (Connecticut Sea Grant), Washington DC, Silver Spring MD.. Pp. <missing location>

de Rivera, Catherine, and 27 authors (2005) Broad-scale non-indigenous species monitoring along the West Coast in National Marine Sanctuaries and National Estuarine Research Reserves report to National Fish and Wildlife Foundation, National Fish and Wildlife Foundation, Washington, D.C.. Pp. <missing location>

Fairey, Russell; Dunn, Roslyn; Sigala, Marco; Oliver, John (2002) Introduced aquatic species in California's coastal waters: Final Report, California Department of Fish and Game, Sacramento. Pp. <missing location>

Fisheries and Oceans Canada 2018b Haplosporidium costale (SSO) of Oysters. https://www.dfo-mpo.gc.ca/science/aah-saa/diseases-maladies/hcoy-eng.html



Green, Stephanie J. and 7 authors (2021) Broad-scale acoustic telemetry reveals long-distance movements and large home ranges for invasive lionfish on Atlantic coral reefs, Marine Ecology Progress Series 673: 117-134

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Lambert, Charles C; Lambert, Gretchen (2003) Persistence and differential distribution of nonindigenous ascidians in harbors of the Southern California Bight., Marine Ecology Progress Series 259: 145-161

Low-Pfeng, Antonio; Recagno, Edward M. Peters (2012) <missing title>, Geomare, A. C., INESEMARNAT, Mexico. Pp. 236

Nishikawa, T. (1991) The ascidians of the Japan Sea. II., Publications of the Seto Marine Biological Laboratory 35: 25-170

Rajagopal, S.;Nair, K.V.K.; Van Der Velde, G.; Jenner, H.A. (1997) Seasonal settlement and succession of fouling communities in Kalpakkam, east coast of India., Netherlands Journal of Aquatic Ecology 30(4): 309-325

Rajogopal, Sanjeevi and 7 authors (2005) Thermal tolerance of the invasive oyster Crassostrea gigas: Feasibility of heat treatment as an antifouling option., Water Research 39: 4334-4342

Rho, Boon Jo; Choe, Byung Lae; Song, Jun-Im; Lee Young Ja (2000) Ascidians of Tangsa and its adjacent waters in Korea strait., Korean Journal of Systematic Zoology 16(1): 39-53

Ritter, W. E.; Forsyth, R. A. (1917) Ascidians form the littoral zone of southern California, University of California Publications in Zoology 16: 439-512

Rodriguez, Laura F.; Ibarra-Obando, Silvia E. (2008) Cover and colonization of commercial oyster (Crassostrea gigas) shells by fouling organisms in San Quintin Bay, Mexico, Journal of Shellfish Research 27(2): 337-343

Ruiz, Gregory M.; Geller, Jonathan (2018) Spatial and temporal analysis of marine invasions in California, Part II: Humboldt Bay, Marina del Re, Port Hueneme, and San Francisco Bay, Smithsonian Environmental Research Center & Moss Landing Laboratories, Edgewater MD, Moss Landing CA. Pp. <missing location>

Ruiz, Gregory; Geller, Jonathan (2021) Spatial and temporal analysis of marine invasions: supplemental studies to evaluate detection through quantitative and molecular methodologies, Marine Invasive Species Program, California Department of Fish and Wildlife, Sacramento CA. Pp. 153 ppl.

Simkanin, Christina; Fofonoff, Paul W.; Larson, Kriste; Lambert, Gretchen; Dijkstra, Jennifer A.; Ruiz, Gregory M. (2016) Spatial and temporal dynamics of ascidian invasions in the continental United States and Alaska, Marine Biology 163: Published online

Tracy, Brianna M.; Reyns, Nathalie B. (2014) Spatial and temporal patterns of native and invasive ascidian assemblages in a Southern California embayment, Aquatic Invasions 9: In press

Wasson, Kerstin; Zabin, C. J.; Bedinger, L.; Diaz, M. C.; Pearse J. S. (2001) Biological invasions of estuaries without international shipping: the importance of intraregional transport, Biological Conservation 102: 143-153

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