NEMESIS Bioregion Distribution:


Native  Introduced  Cryptogenic  Failed


First Non-native North American Marine/Estuarine Record: 1983
First Non-native East/Gulf Coast Marine/Estuarine 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 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of A. aspersa were found on fouling plates in Chesapeake Bay, at Gloucester Point, in the York River (Ruiz et al., unpublished data), but live animals were not seen.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).