NEMESIS Bioregion Distribution:


Native  Introduced  Cryptogenic  Failed


First Non-native North American Marine/Estuarine Record: 2000
First Non-native West Coast Marine/Estuarine Record: 2000



General Invasion History:

Polyclinum constellatum was described from Mauritius in 1816. It is widely reported from mangroves, dead corals, rocks, and from man-made structures, such as pilings, floats, buoys, etc. (da Rocha et al. 2010; Carlton and Eldredge 2009). Although its discovery in Mauritius suggests an Indian Ocean origin, native status in the tropical Atlantic cannot be excluded. By the end of the 19th century, it was reported from the Gulf of Mexico (in 1887, Florida), the Caribbean Sea (in 1883, Jamaica), Hawaii (in 1873), and Japan (in 1900) (US National Museum of Natural History 2002; Carlton and Eldredge 2009). We consider it cryptogenic in the western Atlantic, Indian Ocean, and the western Pacific. Polyclinum constellatum is considered introduced in Guam (Lambert 2002; Lambert 2003), Tahiti (Monniot and Monniot 1985), and the Hawaiian Islands (Carlton and Eldredge 2009). It was found at the western entrance to the Panama Canal in 2002-2009 (Ruiz et al., unpublished data; Carman et al. 2010) where Carman et al (2010) considered it cryptogenic. In 2008-2009, it was found in Pacific Mexico, near Mazatlan, at the mouth of the Gulf of California (Tovar-Hernandez et al. 2010). One specimen was identfied on fouling plates in San Diego Bay in 2000 (Ruiz et al., unpublished data).

North American Invasion History:

Invasion History on the West Coast:

In the summer of 2000, a single specimen of Polyclinum constellatum was identified on settlement plates from Navy Pier 14 in San Diego (Ruiz et al., unpublished data). The population status of this species in southern California is not known. In 2008-2009, it was discovered further south, in the Urias estuary, near the port of Mazatlan, Mexico, and in a nearby oyster farm (Tovar-Hernández et al. 2010).

Invasion History on the East Coast:

Van Name (1921; 1945) mentions the occurrence of Polyclinum constellatum on the west coast of Florida, but not on the east coast. However, Weiss (1948) found it on fouling plates in Biscayne Bay in 1944-1946. It was found in Bermuda before 1972 (Monniot 1972). Currently, it is known from waters off Georgia (in 1981, USNM 24319), the Indian River Lagoon (Mook 1983, Ruiz et al. unpublished), and Biscayne Bay (Weiss 1948; Ruiz et al., unpublished data).

Invasion History on the Gulf Coast:

The first collection of Polyclinum constellatum in US waters was in Cedar Key, Florida, in the Gulf of Mexico in 1887 (USNM 6975, US National Museum of Natural History 2010). It was collected in the Dry Tortugas in the 1880s ( USNM 7137, US National Museum of Natural History 2010, exact date unknown); Cedar Key, Florida in 1887; Tampa Bay (Gretchen Lambert 2003, personal communication); and South Padre Island, Texas in 2004 (Lambert et al. 2005). As noted above, we consider this tunicate cryptogenic in the western Atlantic.

Invasion History in Hawaii:

The first Hawaiian record for Polyclinum constellatum is from Oahu in 1873 (Carlton and Eldredge 2009). Subsequently it was reported from Pearl Harbor in 1920 (Coles et al. 1999b, Carlton and Eldredge 2009); Honolulu Harbor in 1997 (Coles et al. 1999a); Ala Wai Harbor in 1998 (Coles et al. 1999a); Kaneohe Bay in 1999 (Coles et al. 2002); and Waikiki in 2001 (Coles et al. 2002). In Hawaii, this tunicate occurs on floats and pilings, but also on dead coral, and under rocks at exposed locations (Carlton and Eldredge 2009).

Invasion History elsewhere in the World:

Polyclinum constellatum was described from Mauritius in 1816. Although its discovery in Mauritius suggests an Indian Ocean origin, native status in the tropical Atlantic cannot be excluded. Because of this uncertainty, it is considered to be cryptogenic throughout much of its global range. It was reported from Jamaica in 1883 and Japan in 1900 (US National Museum of Natural History 2002; Carlton and Eldredge 2009). Polyclinum constellatum is widely distributed throughout the Caribbean (Van Name 1945) and has also been reported from Tahiti (Monniot and Monniot 1985), New Caledonia (Monniot 1987), Tanzania (Monniot and Monniot 1997) and Brazil (da Rocha and Costa 2005). During 2009, P. constellatum was found on the Atlantic and Pacific sides of the Panama Canal (Carman et al. 2011), where Carman et al (2011) considered it to be cryptogenic.

In 1998, Polyclinum constellatum was collected on man-made substrates in Apra Harbor, Guam (USNM 25073, US National Museum of Natural History 2010; Lambert 2002; Lambert 2003) and we consider it introduced here. In 2016, it was collected from docks in two harbors on Santa Cruz Island, in the Galapagos, its first record there (Lambert 2009).