| Species |
Recipient region |
Date of the first record |
|
| Agarophyton vermiculophyllum | Italy / Adriatic Sea | 2008 |  |
| Agarophyton vermiculophyllum | Mexico / California Current | 1979 | |
| Agarophyton vermiculophyllum | Netherlands | 1994 | |
| Agarophyton vermiculophyllum | Norway / North Sea | 2012 | |
| Agarophyton vermiculophyllum | Portugal / Iberian Coastal | From 1989 | |
| Agarophyton vermiculophyllum | Spain / Iberian Coastal | To 2003 | |
| Agarophyton vermiculophyllum | Sweden / North Sea | 2003 | |
| Agarophyton vermiculophyllum | United Kingdom (Britain) / Celtic seas | 2008 - 2013 | |
| Agarophyton vermiculophyllum | United Kingdom (Britain) / English Channel | 2015 | |
| Agarophyton vermiculophyllum | USA / California Current | 1994 | |
| Agarophyton vermiculophyllum | USA / Gulf of Alaska | 2017 | |
| Agarophyton vermiculophyllum | USA / Hudson river | 2000 | |
| Agarophyton vermiculophyllum | USA / Mid-Atlantic Bight | To 1998 | |
| Aglaothamnion cordatum | Portugal / Azores | 2005 - 2007 | |
| Aglaothamnion feldmanniae | France / Western Mediterranean | 1979 | |
| Aglaothamnion feldmanniae | Italy / Adriatic Sea | 2003 | |
| Aglaothamnion feldmanniae | Italy / Western Mediterranean | 1975 | |
| Aglaothamnion feldmanniae | United Kingdom (Britain) / English Channel | | |
| Aglaothamnion halliae | Denmark / Baltic Sea | 2003 | |
| Aglaothamnion halliae | Denmark / North Sea | 2003 | |
| Aglaothamnion halliae | Germany / North Sea | 1960 | |
| Aglaothamnion halliae | Italy / Adriatic Sea | 2016 | |
| Aglaothamnion halliae | Norway / North Sea | 1980 - 1989 | |
| Aglaothamnion halliae | Sweden / North Sea | 2003 | |
| Ahnfeltiopsis flabelliformis | France / Western Mediterranean | 1995 | |
| Ahnfeltiopsis furcellata | Turkey / Black Sea | 1990 - 1999 | |
| Aiptasia diaphana | Portugal / Madeira | 1994 | |
| Aiptasia pulchella | France / Biscay Gulf | 1973 | |
| Aiptasia pulchella | France / Celtic seas | 1974 | |
| Akashiwo sanguinea | Denmark / Baltic Sea | 1983 | |
| Akashiwo sanguinea | Denmark / North Sea | 1982 | |
| Alectryonella plicatula | Israel | 2005 | |
| Alepes djedaba | Greece / Central Mediterranean | 1987 | |
| Alepes djedaba | Greece / Eastern Mediterranean | 1960 | |
| Alepes djedaba | Israel | 1924 - 1925 | |
| Alexandrium acatenella | Ukraine / Black Sea | From 2001 | |
| Alexandrium affine | France / Biscay Gulf | 1987 | |
| Alexandrium affine | France / English Channel | 1988 | |
| Alexandrium affine | Ukraine / Black Sea | From 2001 | |
| Alexandrium catenella | Australia / Bass strait | 1988 | |
| Alexandrium catenella | France / Western Mediterranean | To 1998 | |
| Alexandrium leei | Denmark / Baltic Sea | 2006 | |
| Alexandrium leei | Denmark / North Sea | 2006 | |
| Alexandrium leei | France / Biscay Gulf | 1993 | |
| Alexandrium leei | France / Celtic seas | 1995 | |
| Alexandrium leei | France / English Channel | 1993 | |
| Alexandrium leei | Netherlands | 1991 | |
| Alexandrium margalefii | Denmark / Baltic Sea | 2006 | |
| Alexandrium margalefii | Denmark / North Sea | 2006 | |
| Alexandrium minutum | Bulgaria | 2008 | |
