| Species |
Recipient region |
Date of the first record |
|
| Ulva australis | France / Biscay Gulf | 2005 - 2007 |  |
| Ulva australis | France / English Channel | 1994 | |
| Ulva australis | France / Western Mediterranean | 1984 | |
| Ulva australis | Germany / North Sea | To 2014 | |
| Ulva australis | Italy / Adriatic Sea | 2010 | |
| Ulva australis | Netherlands | 1993 | |
| Ulva californica | Germany / North Sea | 2007 - 2008 | |
| Ulva californica | Ireland | 2006 | |
| Ulva californica | Italy / Adriatic Sea | 2011 | |
| Ulva chaugulii | Israel | 2015 | |
| Ulva compressa | Australia / Bass strait | 1977 | |
| Ulva gigantea | Germany / North Sea | 2015 | |
| Ulva intestinalis | Australia / Bass strait | 1981 | |
| Ulva lactuca | Australia / Bass strait | 1978 | |
| Ulva lactuca | France / Biscay Gulf | 1993 | |
| Ulva lactuca | France / Western Mediterranean | 1993 | |
| Ulva lactuca | Portugal / Azores | 2005 - 2007 | |
| Ulva lactuca | Romania | 1948 | |
| Ulva lactuca | Turkey / Black Sea | 1988 | |
| Ulva ohnoi | France / English Channel | 2015 | |
| Ulva ohnoi | Israel | 2002 | |
| Ulva ohnoi | Italy / Central Mediterranean | 2011 - 2013 | |
| Ulva pertusa | France / Western Mediterranean | 1984 | |
| Ulva pertusa | Netherlands | 1993 | |
| Ulva pertusa | Portugal / Iberian Coastal | From 2007 | |
| Ulva pertusa | Spain / Iberian Coastal | To 2009 | |
| Ulva rigida | Australia / Bass strait | 1983 | |
| Ulva rigida | Iceland | 1972 | |
| Ulva stenophylla | Australia / Bass strait | 1988 | |
| Ulva tepida | Israel | 2002 | |
| Ulvaria obscura | France / Western Mediterranean | 1985 | |
| Ulvaria obscura | Italy / Adriatic Sea | 2000 | |
| Ulvaria splendens | Netherlands | 2018 | |
| Umbraulva dangeardii | Germany / North Sea | 2014 | |
| Umbraulva olivascens | United Kingdom (Britain) / English Channel | 1960 | |
| Undaria pinnatifida | Australia / Bass strait | 1996 | |
| Undaria pinnatifida | Belgium | 1999 | |
| Undaria pinnatifida | France / Biscay Gulf | 1983 | |
| Undaria pinnatifida | France / Celtic seas | 1983 | |
| Undaria pinnatifida | France / English Channel | 1983 | |
| Undaria pinnatifida | France / North Sea | 1986 | |
| Undaria pinnatifida | France / Western Mediterranean | 1971 | |
| Undaria pinnatifida | Germany / North Sea | 2016 | |
| Undaria pinnatifida | Ireland | 2012 | |
| Undaria pinnatifida | Italy / Adriatic Sea | 1992 | |
| Undaria pinnatifida | Italy / Central Mediterranean | 1998 | |
| Undaria pinnatifida | Netherlands | 1999 | |
| Undaria pinnatifida | New Zealand / New Zealand Shelf / North Island | To 1987 | |
| Undaria pinnatifida | New Zealand / New Zealand Shelf / South Island | To 1990 | |
| Undaria pinnatifida | Portugal / Iberian Coastal | To 2007 | |
| Undaria pinnatifida | Spain / Iberian Coastal | 1988 | |
| Undaria pinnatifida | United Kingdom (Britain) / Celtic seas / Channel Islands | 1990 - 1999 | |
| Undaria pinnatifida | United Kingdom (Britain) / English Channel | 1994 | |
| Undaria pinnatifida | United Kingdom (Britain) / North Sea | 2009 | |
| Undatella quadrata | Ukraine / Black Sea | From 1985 | |
| Upeneus moluccensis | Greece / Central Mediterranean | 1976 | |
| Upeneus moluccensis | Greece / Eastern Mediterranean | 1947 | |
| Upeneus moluccensis | Israel | 1946 | |
| Upeneus pori | Greece / Central Mediterranean | 2014 | |
| Upeneus pori | Greece / Eastern Mediterranean | 2003 | |
| Upeneus pori | Israel | 1953 | |
| Upeneus pori | Italy / Central Mediterranean | 2012 | |
| Urnatella gracilis | Romania | 1950 | |
| Urnatella gracilis | Russia / Black Sea | 1950 | |
| Urnatella gracilis | Ukraine / Black Sea | From 1954 | |
| Urocaridella pulchella | Israel | 2016 | |
| Uronema marinum | Italy / Adriatic Sea | From 2008 | |
| Urosalpinx cinerea | France / Biscay Gulf | 1960 | |
| Urosalpinx cinerea | France / Celtic seas | 1969 | |
| Urosalpinx cinerea | France / English Channel | 1970 | |
| Urosalpinx cinerea | France / North Sea | 1960 | |
| Urosalpinx cinerea | Netherlands | 2007 | |
| Urosalpinx cinerea | United Kingdom (Britain) / North Sea | To 1928 | |
