Invasion History

First Non-native North American Tidal Record: 1983
First Non-native West Coast Tidal Record: 2018
First Non-native East/Gulf Coast Tidal Record: 1983

General Invasion History:

Ascidiella aspersa was described from the Adriatic Sea in 1776. Its native range extends from southern Norway and Denmark, through the English Channel and Irish Sea to the Mediterranean (Kott 1998). Ascidiella aspersa has been widely introduced around the world, including the northwest Atlantic from Connecticut to Maine, the southwest Atlantic (Argentina), the southeast Atlantic (South Africa), the Indian Ocean (India), and the southwest Pacific (Australia, New Zealand).

North American Invasion History:

Invasion History on the West Coast:

In 2019, Ascidiella aspersa was collected from fouling plates in San Pedro Bay (ruiz et al. unpublished data, Nydam et al. 2022). In subsequent surveys, it was found to have a wider distribution in southern California from Ventrua Harbor to San Diego Bay (Nydam et al. 2022).

Invasion History on the East Coast:

In 1983, Ascidiella aspersa was collected in the Cape Cod Canal (Richard Whittaker, personal communication to James T. Carlton) and in 1985, in Long Island Sound, probably near Avery Point, Connecticut. It now ranges from Long Island Sound to Mahone Bay, Nova Scotia (Whitlach and Osman 2000; MIT Sea Grant 2006; Moore et al. 2014). We have no records of this species between Long Island Sound and Chesapeake Bay, but we know of no recent studies of fouling organisms in this region. In the summer of 2002, tunics of A. aspersa were found on fouling plates in Chesapeake Bay, at Gloucester Point, in the York River (Ruiz et al., unpublished data), but live animals were not seen. Further sampling is needed to determine whether this tunicate is established in Chesapeake Bay. In 2012, the range of A. aspersa was extended north to Lunenburg Harbor, Nova Scotia, where extensive populations occurred in the inner harbor (Moore et al. 2014).

Invasion History Elsewhere in the World:

Ascidiella aspersa is abundant in parts of southern Australia, where it was probably introduced before 1899 (Kott 1985; Kott 1998; Keough and Ross 1999). In New Zealand, it was first collected in the early 1900s (Cranfield et al. 1998). It was recorded in India in 1976 from Madras on the Bay of Bengal (Nagabhushanam and Krishnamoorthy 1991). In 2010, A. aspersa was discovered in ports on the west, south, and east coasts of South Korea (Pyo et al. 2012). In 2012, it was found on the west coast of Hokkiado in northern Japan (Lutaenko et al. 2013). On the southern coast of South Africa, it occurs from Saldanha Bay to Port Elizabeth, but its date of introduction is unknown (Monniot et al. 2001). Across the Atlantic, in Argentina, it was first collected in several locations in 1962, and is now established in several harbors covering more than 5 degrees of latitude, from Chubut to Puerto Deseado (U.S. Museum of Natural History 2006; Tatián et al. 2010).

Description

Ascidiella aspersa is a solitary tunicate. It is oval-shaped, wider near the base and narrower at the top where the two siphons protrude, the oral siphon extends off the top and the atrial siphon extends off the side about a third of the way down the body. It grows up to 130 mm long and is usually attached on the posterior left side. The siphons are short and conical (cone-shaped) and ridged with 8-10 branchial lobes and six atrial lobes. Papillae are scattered over the body surface, especially on the right side and near the apertures. The test (outer covering) is firm but thin, rough and gristly, gray, black or brownish in color, and often with attached debris (Kott 1985, MarLin 2006).

Taxonomy

Taxonomic Tree

Kingdom:		Animalia
Phylum:		Chordata
Subphylum:		Tunicata
Class:		Ascidiacea
Order:		Phlebobranchia
Family:		Ascidiidae
Genus:		Ascidiella
Species:		aspersa

Synonyms

Ascidia aculeata (Alder, 1863)
Ascidia affinis (Hancock, 1870)
Ascidia albida (Alder and Hancock, 1848)
Ascidia cristata (Risso, 1826)
Ascidia expansa (Kiare, 1893)
Ascidia minuta (Kiare, 1893)
Ascidia normanni (Alder and Hancock, 1870)
Ascidia opalina (MacGillivray, 1843)
Ascidia patula (Müeller, 1776)
Ascidia pedunculata (Hoffman, 1829)
Ascidia pellucida (Alder and Hancock, 1848)
Ascidia scabra (Müeller, 1776)
Ascidia sordida (Alder and Hancock, 1848)
Ascidia truncata (Herdman, 1881)
Ascidia aspersa (Müeller, 1776)
Phallusia aspersa (Trausted, 1883)
Ascidiella cristata (Roule, 1884)
Ascidia elliptica (Alder and Hancock, 1848)
Ascidia pustulosa (Alder, 1863)
Ascidia triangularis (Herdman, 1881)

Potentially Misidentified Species

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. The eggs of A. ascidiacea are unusual, because they float in seawater of 30-35 PSU (Berrill 1928, cited by Mackenzie 2011). 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). The life cycle is annual, with animals becoming senescent within 18 months after settlement (Millar 1954, cited by Makenzie 2011).

Food:

Phytoplankton

Consumers:

fish, crabs

Trophic Status:

Suspension Feeder

SusFed

Habitats

General Habitat	Coarse Woody Debris	None
General Habitat	Marinas & Docks	None
General Habitat	Rocky	None
General Habitat	Vessel Hull	None
General Habitat	Unstructured Bottom	None
General Habitat	Grass Bed	None
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Vertical Habitat	Epibenthic	None

Life History

Tolerances and Life History Parameters

Maximum Temperature (ºC)	26	Animals from Madras, India- Nagabhushanam and Krishnamoorthy 1992
Minimum Salinity (‰)	18	Typical Black Sea salinity, Field, Norway (Dybern 1969(
Maximum Salinity (‰)	36	Animals from Madras, India- Nagabhushanam and Krishnamoorthy 1992
Minimum Duration	1	Animals from Germany, Egg + Larva- Niermann-Kerkenberg and Hofman 1989
Maximum Duration	1.5	Animals from Madras, India- Egg + Larva- Nagabhushanam and Krishnamoorthy 1992
Minimum Length (mm)	60	Kott 1985; Nagabhushanam and Krishnamoorthy 1991
Maximum Length (mm)	130	MarLin 2006
Broad Temperature Range	None	Cold temperate-Tropical
Broad Salinity Range	None	Polyhaline-Euhaline

General Impacts

Economic Impacts

Ascidiella aspersa can foul aquaculture gear (Carman et al. 2010).

Ecological Impacts

Ascidiella aspersa can compete with native species for space and may impact the recruitment success of other species (Osman and Whitlach 2000).

Regional Impacts

NA-ET3	Cape Cod to Cape Hatteras	Ecological Impact	Competition
In Long Island Sound, 'Ascidiella's primary effect was the reduction of available substrate on which other species could recruit successfully' (Osman and Whitlach 2000).
NA-ET3	Cape Cod to Cape Hatteras	Economic Impact	Fisheries
Ascidiella aspersa was found fouling aquaculture gear at eight sites, and cultured Bay Scallops (Argopecten irradians) at two sites, of 26 aquaculture sites surveyed on Marthas Vineyard (Carman et al. 2010).
N195	_CDA_N195 (Cape Cod)	Economic Impact	Fisheries
Ascidiella aspersa was found fouling aquaculture gear at eight sites, and cultured Bay Scallops (Argopecten irradians) at two sites, of 26 aquaculture sites surveyed on Marthas Vineyard (Carman et al. 2010).
M040	Long Island Sound	Ecological Impact	Competition
Long Island Sound, 'Ascidiella's primary effect was the reduction of available substrate on which other species could recruit successfully' (Osman and Whitlach 2000).
NWP-4b	None	Economic Impact	Fisheries
Ascidiella aspersa has damaged the the culture of the Japanese Weathervane Scallop (Mizuhopecten yessoensis) in hanging cages in Funka Bay, Hokkaido (Kanamori et al. 2017)
MA	Massachusetts	Economic Impact	Fisheries
Ascidiella aspersa was found fouling aquaculture gear at eight sites, and cultured Bay Scallops (Argopecten irradians) at two sites, of 26 aquaculture sites surveyed on Marthas Vineyard (Carman et al. 2010).

Regional Distribution Map

Bioregion	Region Name	Year	Invasion Status	Population Status
NEA-II	None	0	Native	Estab
NEA-III	None	0	Native	Estab
AR-V	None	0	Native	Estab
MED-II	None	0	Native	Estab
WA-I	None	1995	Def	Estab
CIO-II	None	1976	Def	Estab
AUS-IV	None	1962	Def	Estab
AUS-V	None	1952	Def	Estab
AUS-VII	None	1952	Def	Estab
AUS-VIII	None	1899	Def	Estab
AUS-IX	None	1952	Def	Estab
NZ-IV	None	1946	Def	Estab
NZ-VI	None	1946	Def	Estab
NA-ET3	Cape Cod to Cape Hatteras	1983	Def	Estab
MED-VII	None	0	Native	Estab
SA-I	None	1962	Def	Estab
NEA-V	None	0	Native	Estab
MED-IX	None	0	Native	Estab
MED-VIII	None	0	Native	Estab
MED-VI	None	0	Native	Estab
MED-V	None	0	Native	Estab
MED-IV	None	0	Native	Estab
MED-III	None	0	Native	Estab
MED-I	None	0	Native	Estab
NEA-IV	None	0	Native	Estab
NA-ET2	Bay of Fundy to Cape Cod	2000	Def	Estab
WA-IV	None	2001	Def	Estab
WA-V	None	2001	Def	Estab
M040	Long Island Sound	1985	Def	Estab
M010	Buzzards Bay	1983	Def	Estab
M020	Narragansett Bay	1997	Def	Estab
M130	Chesapeake Bay	2002	Def	Unk
N180	Cape Cod Bay	2000	Def	Estab
N170	Massachusetts Bay	2000	Def	Estab
N100	Casco Bay	2003	Def	Estab
B-I	None	0	Native	Estab
N130	Great Bay	2006	Def	Estab
N195	_CDA_N195 (Cape Cod)	2007	Def	Estab
N140	Hampton Harbor	2007	Def	Estab
RS-3	None	2003	Def	Estab
M023	_CDA_M023 (Narragansett)	2009	Def	Estab
NWP-4a	None	2010	Def	Estab
NWP-3a	None	2010	Def	Estab
NWP-4b	None	2012	Def	Estab
NA-ET1	Gulf of St. Lawrence to Bay of Fundy	2012	Def	Estab
AR-IV	None	2018	Def	Estab
NEP-VI	Pt. Conception to Southern Baja California	2018	Def	Estab
P050	San Pedro Bay	2018	Def	Estab
P064	_CDA_P064 (Ventura)	2021	Def	Estab
P040	Newport Bay	2021	Def	Estab
P020	San Diego Bay	2021	Def	Estab
P040	Newport Bay	2019	Def	Estab

Occurrence Map

OCC_ID	Author	Year	Date	Locality	Status	Latitude	Longitude
4420	Berger and Whitlach 1997	1985	1985-01-01	Avery Point, Groton	Def	41.3154	-72.0634
4421	Whitlach and Osman 2000	1997	1997-01-01	Jamestown	Def	41.4971	-71.3673
4422	MIT Sea Grant 2003	2000	2000-08-11	Fall River	Def	41.7062	-71.1620
4423	MIT Sea Grant 2003	2000	2000-08-15	Colt State Park, Bristol	Def	41.6698	-71.3009
4424	MIT Sea Grant 2003	2000	2000-08-15	Roger Williams University dock	Def	41.6484	-71.2609
4425	MIT Sea Grant 2003	2000	2000-08-17	Potters Cove, Prudence Island	Def	41.6423	-71.3414
4426	MIT Sea Grant 2003	2000	2000-08-16	North Kingstown	Def	41.6237	-71.4126
4427	MIT Sea Grant 2003	2000	2000-08-17	Prudence Island T-Wharf, Bay Islands Park	Def	41.5882	-71.3245
4428	MIT Sea Grant 2003	2000	2000-08-15	Wickford Marina, Wickford	Def	41.5754	-71.4423
4429	MIT Sea Grant 2003	2000	2000-08-06	Newport Shipyard, Newport	Def	41.4901	-71.3217
4430	MIT Sea Grant 2003	2000	2000-08-06	Coasters Harbor, Newport	Def	41.5107	-71.3270
4431	MIT Sea Grant 2003	2000	2000-08-10	Woods Hole	Def	41.5254	-70.6725
4433	MIT Sea Grant 2003	2000	2000-08-10	Sandwich Marina	Def	41.7704	-70.5036
4434	MIT Sea Grant 2003	2000	2000-08-07	Deer Island, Boston	Def	42.3518	-70.9606
4435	MIT Sea Grant 2003	2000	2000-08-07	Rowes Wharf, Boston	Def	42.3570	-71.0409
4436	MIT Sea Grant 2003	2000	2000-08-08	Hawthorne Cove Marina, Salem	Def	42.5220	-70.8823
4437	MIT Sea Grant 2003	2000	2000-08-08	Tucks Point Marina, Beverly	Def	42.5676	-70.7787
4438	MIT Sea Grant 2003	2000	2000-08-08	Gloucester State Pier	Def	42.6158	-70.6625
4439	MIT Sea Grant 2003	2003	2003-08-04	ort Harbor Marine, South Portland	Def	43.6414	-70.2414
4440	MIT Sea Grant 2003	2003	2003-08-04	Portland Yacht Services	Def	43.6651	-70.2401
6041	Carman et al. 2009	2007	2007-06-01	Martha's Vineyard	Def	41.4579	-70.5866
6823	MIT Sea Grant 2011	2009	2009-09-16	Mystic Marine Fuel, Mystic	Def	41.3334	-71.9759
6824	MIT Sea Grant 2011	2009	2009-07-16	Point Judith Marina, Matunuck	Def	41.3788	-71.5169
7344	Kott 1998	None	9999-01-01	Provence	Native	43.0000	6.0000
7345	Mueller 1776, cited by Kott 1985	None	9999-01-01	Adriatic Sea	Native	43.0000	14.0000
7346	Mueller 1776, cited by Kott 1998	None	9999-01-01	Oslofjord	Native	59.3500	10.5833
7347	Hoffman 1829, cited by Kott 1998	None	9999-01-01	Helgoland	Native	54.1825	7.8853
7348	Macgillivray 1843, cited by Kott 1998	None	9999-01-01	Aberdeen	Native	57.1526	2.1100
7349	Alder and Hancock 1848, cited by Kott 1998	None	9999-01-01	Cullercoats	Native	55.0333	-1.4333
7350	Kott 1998	None	9999-01-01	Lamlash Bay	Native	55.5373	5.1235
7351	Alder 1849, cited by Kott 1998	None	9999-01-01	Bantry Bay	Native	51.6500	-9.7167
7352	Alder 1863, cited by Kott 1998	None	9999-01-01	Fowey Harbour	Native	50.3343	4.6329
7353	Hancock 1870, cited by Kott 1998	None	9999-01-01	Roach River	Native	51.5833	0.8000
7354	Kiaer, 1893, cited by Kott 1998	None	9999-01-01	Aure	Native	63.2686	8.6078
7355	Kiaer, 1893, cited by Kott 1998	None	9999-01-01	Bergen	Native	60.3894	5.3330
7356	US National Museum of Natural History 2012	None	9999-01-01	Spain	Native	45.5000	-13.5300
7358	US National Museum of Natural History 2012	None	9999-01-01	Naples, Zoological Station	Native	40.8450	14.2583
7359	Mastrototaro and Dappiano 2005	None	9999-01-01	Taranto, Mar Piccolo	Native	40.4667	17.2333
7360	Monniot and Monniot 1994	None	9999-01-01	Cap Vert	Native	14.7447	-17.5203
7361	Naranjo et al. 1996	None	9999-01-01	Algeceiras	Native	36.1311	-5.3960
7362	Koukouros et al. 1996	None	9999-01-01	Aegean Sea	Native	39.0000	23.0000
7363	Koukouros et al. 1996	None	9999-01-01	Black Sea	Native	44.6133	33.5300
7364	Chebbi et al. 2010	None	9999-01-01	Bizerte Lagoon	Native	37.2667	9.8667
7369	Dinçaslan et al. 2007	None	9999-01-01	Izmir Bay	Native	38.4220	27.1290
7370	Koukouros et al. 1996	None	9999-01-01	Levantine Basin, Mediterranean S	Native	34.0000	35.5000
7371	Gemarec and Monniot 1966	None	9999-01-01	south coast, Britann	Native	47.6600	-3.5000
7372	El Nagar et al. 2010	2009	2009-01-01	Muros	Native	42.7760	-9.0580
7373	OBIS, in Appeltans et al. 2012	None	9999-01-01	Morocco	Native	32.5000	-8.0000
7374	Tatian et al. 2010	1962	1962-01-18	Punta Pardelas	Def	-42.6167	-64.2667
7375	U.S. National Museum of Natural History 2006	1978	1978-07-18	Nintas Point, Chubut	Def	-42.8833	-64.7000
7376	Tatian et al. 2010	1962	1962-02-12	Puerto Madryn	Def	-42.7667	-65.0500
7377	Tatian et al. 2010	2007	2007-05-22	Puerto Deseado	Def	-47.7500	-65.9167
7378	Monniot et al. 2001	2001	2001-01-01	Saldanha Bay Harbour	Def	-33.0347	18.0097
7379	Monniot et al. 2001	2001	2001-01-01	Cape Town Harbour	Def	-33.9253	18.4239
7380	Monniot et al. 2001	2001	2001-01-01	Port Elizabeth	Def	-33.9581	24.6000
7381	Emara and Belal 2004	2003	2003-01-01	Lake Timsah and Bitter Lakes, Suez Canal	Def	30.3333	32.3833
7382	Nagabhushanam and Krishnamoorthy 1992	1976	1976-01-01	Chennai (Madras)	Def	13.0839	80.2700
7383	Rajagopal et al. 1997	1990	1990-01-01	Kalpakkam	Def	12.5576	80.1754
7384	Kott 1985	1985	1985-01-01	Swan River estuary	Def	-31.9472	115.9161
7385	Kott 1985	1985	1985-01-01	Bunbury	Def	-33.3400	115.6419
7386	Kott 1985; Huisman et al. 2008	1952	1952-01-01	Albany	Def	-35.0228	117.8814
7387	Kott 1985, Huisman et al. 2008	1985	1985-01-01	Esperance	Def	-33.8611	121.8814
7388	Wiltshire et al. 2010	2001	2010-01-01	Port Adelaide	Def	-34.8461	138.5031
7389	Wiltshire et al. 2010	1996	1996-01-01	Port Lincoln	Def	-34.7322	135.8586
7390	Kott 1985	1899	1989-01-01	Port Phillip Bay	Def	-38.1500	144.8667
7391	Kott 1985	1952	1952-01-01	Entrecasteaux Channel	Def	-43.2167	147.2833
7392	Kott 1985	1985	1985-01-01	Spring Bay, Tasman Sea	Def	-42.2600	147.9700
7393	Kott 1985	1946	1946-01-01	Otago Harbour	Def	-45.8167	170.6500
7394	Cranfield et al. 1998	1998	1998-01-01	Lyttleton Harbour	Def	-43.6167	172.7333
7395	Cranfield et al. 1998	1998	1998-01-01	Portobello	Def	-45.8398	170.6509
7396	Cranfield 1998	1998	1998-01-01	Halfmoon Bay	Def	-46.9000	168.1333

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Ascidiella aspersa

Tunicates