Symplegma reptans

Invasion History

First Non-native North American Tidal Record: 1991
First Non-native West Coast Tidal Record: 1991
First Non-native East/Gulf Coast Tidal Record:

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General Invasion History:

Symplegma reptans is a colonial tunicate, native to the Indo-West Pacific, where it occurs from northern Japan to Hong Kong (Nishikawa 1991; Huang 2001), Mumbai, India (Swami and Chhapgar 2002) and Queensland, Australia (Kott 1985). It has been introduced to Southern California, being first reported from Los Angeles Harbor in 1991.

North American Invasion History:

Invasion History on the West Coast:

Symplegma reptans was first collected in the northeast Pacific in 1991, in Los Angeles Harbor, and in San Diego Bay in 1994, but was initially misidentified as S. brakenhielmi. In 1997, it was found in Mission Bay, Dana Point Harbor, and Long Beach Harbor (Lambert and Lambert 1998; Lambert and Lambert 2003). In 1997-1998, this tunicate underwent a population explosion, creating dense single-species colonies (Lambert and Lambert 2003).

Invasion History in Hawaii:

In 1996, Symplegma reptans was found in Pearl Harbor in fouling on the floating drydock USS 'Machinist', which had been towed from the Philippines (Coles et al. 1999a; Coles et al. 1999b; Carlton and Eldredge, 2009). Its establishment in the Islands is uncertain.

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Description

Symplegma reptans is a colonial tunicate with flattened zooids embedded within a thin, but tough, and nearly transparent tunic. Colonies grow in a flat mat which can be up to 2-3 mm thick, and 300+ mm diameter. Individual zooids are oblong in shape and randomly arranged within the common tunic. The color of the zooids varies from pink (Australia) or grayish to pinkish purple (Japan) with large triangular white patches, around the oral apertures. When the colonies are large and the zooids very densely packed, they form lobes and the pinkish color is much more noticeable. The zooids are usually arranged more randomly than in the photo (above). Each zooid has its own oral and atrial siphon that opens at the surface of the tunic. Both siphons are short, with frilled openings (Kott 1985; Nishikawa 1991; Gretchen Lambert 2012, personal communication).

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Taxonomy

Ecology

General:

A colonial (or compound) tunicate consists of many zooids, bearing most or all of the organs of a solitary tunicate, but modified to varying degrees for colonial life. Colonial ascidians of the genera Symplegma have small, flattened, ovate zooids, but these are not arranged in systems. The zooids are embedded in a mass of tunic material. Each zooid has an oral and atrial siphon. Water is pumped into the oral siphon, through finely meshed ciliated gills on the pharynx, where phytoplankton and detritus is filtered, and passed on mucus strings to the stomach and intestines. Excess waste is expelled in the outgoing atrial water (Van Name 1945; Barnes 1983).

Colonial ascidians reproduce both asexually, by budding, and sexually, from fertilized eggs developing into larvae. Buds can form from the body wall of the zooid. Colonies vary in size, and can range from small clusters of zooids to huge spreading masses. The zooids are hermaphroditic, with eggs and sperm being released to the atrial chamber. Eggs may be self-fertilized or fertilized by sperm from nearby animals, but some species have a partial block to self-fertilization. Eggs are brooded in the atrial chamber, and hatch into tadpole larvae, with a muscular tail and a notochord, eyespots, and a set of adhesive papillae. The lecithotrophic (non-feeding, yolk-dependent) larvae are expelled on hatching, and swim briefly before settlement. Swimming periods are usually less than a day, and some larvae can settle immediately after release, but the larval period can be longer at lower temperatures. On settlement, the tail is absorbed, the gill basket expands, and the tunicate begins to feed by filtering (Van Name 1945; Barnes 1983).

Food:

Phytoplankton, detritus

Trophic Status:

Suspension Feeder

SusFed

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Habitats

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

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Tolerances and Life History Parameters

Broad Temperature Range	None	Warm temperate-Tropical
Broad Salinity Range	None	Polyhaline-Euhaline

General Impacts

Ecological Impacts-

Competition- Symplegma reptans created extensive areas of 100% cover at sites in San Diego and Mission Bays in 1998, suggestive of competition (Lambert and Lambert 2003).

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Regional Impacts

P020	San Diego Bay		Ecological Impact	Competition
Symplegma reptans created extensive areas of 100% cover at sites in San Diego and Mission Bays in 1998, suggestive of competition (Lambert and Lambert 2003).
P030	Mission Bay		Ecological Impact	Competition
Symplegma reptans created extensive areas of 100% cover at sites in San Diego and Mission Bays in 1998, suggestive of competition (Lambert and Lambert 2003).
NEP-VI	Pt. Conception to Southern Baja California		Ecological Impact	Competition
Symplegma reptans created extensive areas of 100% cover at sites in San Diego and Mission Bays in 1998, suggestive of competition (Lambert and Lambert 2003).
CA	California		Ecological Impact	Competition
Symplegma reptans created extensive areas of 100% cover at sites in San Diego and Mission Bays in 1998, suggestive of competition (Lambert and Lambert 2003).

References

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

Bastida-Zavala, Rolando; de León-González, Jesús Ángel; Carballo Cenizo, José Luis; Moreno-Dávila, Betzabé (2014) [Aquatic Invasive Species in Mexico], Comisión Nacional para el Conocimiento y Uso de la Biodiversidad, <missing place>. Pp. 317-336

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

Coles S. L., DeFelice R. C., Eldredge, L. G. (1999a) Nonindigenous marine species introductions in the harbors of the south and west shores of Oahu, Hawaii., Bishop Museum Technical Report 15: 1-212

Coles, S. L.; DeFelice, R. C.; Eldredge, L. G.; Carlton, J. T. (1999b) Historical and recent introductions of non-indigenous marine species into Pearl Harbor, Oahu, Hawaiian Islands., Marine Biology 135(1): 147-158

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>

Huang, Zongguo (Ed.), Junda Lin (Translator) (2001) Marine Species and Their Distributions in China's Seas, Krieger, Malabar, FL. Pp. <missing location>

Kott, P. (1998) Tunicata, Zoological Catalogue of Australia 34: 51-252

Kott, Patricia (1985) The Australian Ascidiacea Part 1, Phlebobranchia and Stolidobranchia., Memoirs of the Queensland Museum 23: 1-440

Lambert, C. C.; Lambert, G. (1998) Non-indigenous ascidians in southern California harbors and marinas., Marine Biology 130: 675-688

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

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>

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

Swami, B. S.; Chapgar, B. F. (2002) Settlement pattern of ascidians in harbor waters of Mumbai, West Coast of India., Indian Journal of Marine Science 31(3): 207-212

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

Van Name, Willard G. (1945) The North and South American ascidians, Bulletin of the American Museum of Natural History 84: 1-462

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