Public domain: Introduction events' accounts (50 / 5528)
| Species |
Recipient region |
Date of the first record |
|
| 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 | |
| Vallicula multiformis | Portugal / Madeira | To 1998 | |
| Vanderhorstia mertensi | Greece / Eastern Mediterranean | 2019 | |
| Vanderhorstia mertensi | Israel | 2012 | |
| Varicopeza pauxilla | Israel | 2016 | |
| Varicorbula erythraeensis | Israel | 2009 | |
| Varicorbula gibba | Australia / Bass strait | 1987 | |
