| Species |
Recipient region |
Date of the first record |
|
| Abra segmentum | Russia / Caspian Sea | 1955 |  |
| Abudefduf sexfasciatus | Greece / Eastern Mediterranean | 2017 | |
| Abudefduf vaigiensis | France / Western Mediterranean | 2000 | |
| Abudefduf vaigiensis | Israel | 1997 | |
| Abudefduf vaigiensis | Italy / Western Mediterranean | 1957 | |
| Acanthogobius flavimanus | Australia / Bass strait | 1990 | |
| Acanthophora nayadiformis | France / Western Mediterranean | To 1977 | |
| Acanthophora nayadiformis | Greece / Central Mediterranean | 1987 | |
| Acanthophora nayadiformis | Greece / Eastern Mediterranean | 1861 | |
| Acanthophora nayadiformis | Israel | 1949 | |
| Acanthosiphonia echinata | Italy / Adriatic Sea | 2018 | |
| Acanthurus chirurgus | Italy / Western Mediterranean | 2012 | |
| Acanthurus coeruleus | Israel | 2014 | |
| Acanthurus monroviae | Portugal / Iberian Coastal | 2007 | |
| Acanthurus sohal | Greece / Eastern Mediterranean | 2017 | |
| Acar plicata | Israel | 1978 | |
| Acartia (Acanthacartia) tonsa | Belgium | 1956 | |
| Acartia (Acanthacartia) tonsa | Bulgaria | 2000 | |
| Acartia (Acanthacartia) tonsa | Denmark / Baltic Sea | 1921 - 1925 | |
| Acartia (Acanthacartia) tonsa | Denmark / North Sea | 1921 | |
| Acartia (Acanthacartia) tonsa | Estonia | 1924 | |
| Acartia (Acanthacartia) tonsa | Finland | 1930 | |
| Acartia (Acanthacartia) tonsa | France / Biscay Gulf | 1927 | |
| Acartia (Acanthacartia) tonsa | France / English Channel | 1927 | |
| Acartia (Acanthacartia) tonsa | France / Western Mediterranean | 1966 | |
| Acartia (Acanthacartia) tonsa | Georgia | 2002 | |
| Acartia (Acanthacartia) tonsa | Germany / Baltic Sea | 1981 | |
| Acartia (Acanthacartia) tonsa | Germany / North Sea | 1930 | |
| Acartia (Acanthacartia) tonsa | Greece / Central Mediterranean | 2005 | |
| Acartia (Acanthacartia) tonsa | Iran / Caspian Sea | From 1981 | |
| Acartia (Acanthacartia) tonsa | Ireland | 2019 | |
| Acartia (Acanthacartia) tonsa | Italy / Adriatic Sea | 1987 - 1988 | |
| Acartia (Acanthacartia) tonsa | Italy / Western Mediterranean | 1986 | |
| Acartia (Acanthacartia) tonsa | Latvia | 1924 | |
| Acartia (Acanthacartia) tonsa | Lithuania | 1920 - 1930 | |
| Acartia (Acanthacartia) tonsa | Netherlands | 1913 - 1915 | |
| Acartia (Acanthacartia) tonsa | Norway / North Sea | 1980 - 2012 | |
| Acartia (Acanthacartia) tonsa | Poland | 1925 | |
| Acartia (Acanthacartia) tonsa | Portugal / Iberian Coastal | To 1985 | |
| Acartia (Acanthacartia) tonsa | Russia / Baltic Sea / Kaliningrad area | 1930 - 1950 | |
| Acartia (Acanthacartia) tonsa | Russia / Baltic Sea / St. Petersburg area | 1934 | |
| Acartia (Acanthacartia) tonsa | Spain / Iberian Coastal | 2001 | |
| Acartia (Acanthacartia) tonsa | Sweden / Baltic Sea | 1934 | |
| Acartia (Acanthacartia) tonsa | Sweden / North Sea | 1920 - 1930 | |
| Acartia (Acanthacartia) tonsa | Turkey / Black Sea | 1996 | |
| Acartia (Acanthacartia) tonsa | Ukraine / Black Sea | From 1976 | |
| Acartia (Acanthacartia) tonsa | United Kingdom (Britain) / English Channel | 1956 | |
| Acartia (Acanthacartia) tonsa | United Kingdom (Britain) / North Sea | 1956 - 1986 | |
| Acartia (Acartiura) clausi | Russia / Caspian Sea | 1981 | |
| Acartia (Acartiura) omorii | France / English Channel | 2004 | |
| Acartia (Acartiura) omorii | France / North Sea | 2004 | |
| Acartia (Odontacartia) centrura | Israel | 1968 | |
| Acentrogobius pflaumii | Australia / Bass strait | 1996 | |
| Achelia sawayai | Italy / Central Mediterranean | 2016 | |
| Achnanthes pseudogroenlandica | Bulgaria | 1984 | |
| Achnanthes pseudogroenlandica | Romania | 1984 | |
| Achnanthes pseudogroenlandica | Ukraine / Black Sea | From 1984 | |
| Acinetospora crinita | Australia / Bass strait | 1971 | |
| Acipenser baeri | Denmark / Baltic Sea | 2005 | |
| Acipenser baeri | Estonia | 1962 | |
| Acipenser baeri | Finland | 1960 - 1970 | |
| Acipenser baeri | France / Biscay Gulf | 1999 | |
| Acipenser baeri | France / Celtic seas | 1999 | |
| Acipenser baeri | Germany / Baltic Sea | 1980 - 1989 | |
| Acipenser baeri | Germany / North Sea | 1980 - 1989 | |
| Acipenser baeri | Latvia | 1962 | |
| Acipenser baeri | Lithuania | 1962 | |
| Acipenser baeri | Netherlands | To 1990 | |
| Acipenser baeri | Poland | 1985 | |
| Acipenser baeri | Russia / Baltic Sea / Kaliningrad area | 1960 - 1969 | |
| Acipenser baeri | Russia / Baltic Sea / St. Petersburg area | 1964 - 1967 | |
| Acipenser gueldenstaedtii | Denmark / Baltic Sea | 1995 | |
| Acipenser gueldenstaedtii | Denmark / North Sea | 2010 | |
| Acipenser gueldenstaedtii | Estonia | 1962 - 1969 | |
| Acipenser gueldenstaedtii | Finland | 2000 | |
| Acipenser gueldenstaedtii | Germany / Baltic Sea | 1990 - 1999 | |
| Acipenser gueldenstaedtii | Latvia | 1962 | |
| Acipenser gueldenstaedtii | Netherlands | To 1990 | |
| Acipenser gueldenstaedtii | Poland | 1985 | |
| Acipenser gueldenstaedtii | Russia / Baltic Sea / St. Petersburg area | 1964 - 1966 | |
| Acipenser gueldenstaedtii | Sweden / Baltic Sea | 1966 | |
| Acipenser ruthenus | Finland | 1958 | |
| Acipenser ruthenus | Latvia | 1888 | |
| Acipenser ruthenus | Lithuania | 1885 | |
| Acipenser ruthenus | Netherlands | To 1990 | |
| Acipenser ruthenus | Poland | 1937 | |
| Acipenser ruthenus | Russia / Baltic Sea / Kaliningrad area | 1885 | |
| Acipenser ruthenus | Russia / Baltic Sea / St. Petersburg area | 1763 | |
| Acipenser ruthenus | Sweden / Baltic Sea | 1887 | |
| Acipenser stellatus | Denmark / Baltic Sea | 2010 | |
| Acipenser stellatus | Finland | 1999 | |
| Acipenser stellatus | Germany / Baltic Sea | To 2006 | |
| Acipenser transmontanus | Germany / North Sea | To 1999 | |
| Acorus calamus | India / Eastern Arabian | 2005 | |
| Acrochaetium catenulatum | Netherlands | 1967 | |
| Acrochaetium kylinii | Turkey / Black Sea | 2000 - 2009 | |
| Acrochaetium leptonema | Bulgaria | 2000 - 2009 | |
| Acrochaetium leptonema | Turkey / Black Sea | 2000 - 2009 | |
| Acrochaetium mahumetanum | Romania | 1938 | |
| Acrochaetium mahumetanum | Turkey / Black Sea | 2000 - 2009 | |
| Acrochaetium mediterraneum | Turkey / Black Sea | 2000 - 2009 | |
| Acrochaetium microscopicum | Turkey / Black Sea | 2000 - 2009 | |
| Acrochaetium moniliforme | Turkey / Black Sea | 2000 - 2009 | |
| Acrochaetium pacificum | Australia / Bass strait | 1981 | |
| Acrochaetium rosulatum | Bulgaria | 1990 - 1999 | |
| Acrochaetium rosulatum | Turkey / Black Sea | 2000 - 2009 | |
| Acrochaetium savianum | Netherlands | 1960 - 1969 | |
| Acrochaetium subpinnatum | Turkey / Black Sea | 2000 - 2009 | |
| Acromegalomma claparedei | Italy / Adriatic Sea | 1987 | |
| Acrothamnion preissii | France / Western Mediterranean | 1981 | |
| Acrothamnion preissii | Italy / Adriatic Sea | 2007 | |
| Acrothamnion preissii | Italy / Central Mediterranean | 1996 | |
| Acrothamnion preissii | Italy / Western Mediterranean | 1969 | |
| Acrothrix gracilis | France / Western Mediterranean | 1993 | |
| Actaea savignyii | Israel | 2010 | |
| Actaeodes tomentosus | Greece / Eastern Mediterranean | 2013 | |
| Acteocina mucronata | Greece / Eastern Mediterranean | 1991 | |
| Acteocina mucronata | Israel | 1986 | |
| Adelosina carinatastriata | France / Biscay Gulf | To 2007 | |
| Aeolidiella indica | Italy / Western Mediterranean | 1968 | |
| Aequorea macrodactyla | Israel | 2013 | |
| Aerococcus viridans | Ireland | 1961 | |
| Aerococcus viridans | United Kingdom (Britain) / Celtic seas | 1985 | |
| Aeromonas salmonicida salmonicida | Norway / Barents Sea | 1986 | |
| Aeromonas salmonicida salmonicida | Norway / North Sea | 1986 | |
| Aeromonas salmonicida salmonicida | Norway / Norwegian Sea | 1986 | |
| Aetea anguina | Australia / Bass strait | 1887 | |
| Aetea anguina | Spain / Canary Islands | To 2003 | |
| Aetea ligulata | Spain / Canary Islands | To 2003 | |
| Aetea longicollis | Spain / Canary Islands | To 2003 | |
| Aetea sica | Spain / Canary Islands | To 2003 | |
| Aetea truncata | Spain / Canary Islands | To 2003 | |
| Afrocardium richardi | Israel | 1997 | |
| Afropinnotheres monodi | Portugal / Iberian Coastal | To 2019 | |
| Afropinnotheres monodi | Spain / Iberian Coastal | 1995 | |
| Agardhiella subulata | France / Western Mediterranean | 1984 | |
| Agardhiella subulata | Italy / Adriatic Sea | 2003 | |
| Agardhiella subulata | Italy / Central Mediterranean | 1987 | |
| Agardhiella subulata | Italy / Western Mediterranean | 2007 | |
| Agardhiella subulata | Netherlands | 1998 | |
| Agarophyton vermiculophyllum | Belgium | To 2011 | |
| Agarophyton vermiculophyllum | Canada / Gulf of Alaska | 2006 | |
| Agarophyton vermiculophyllum | Denmark / Baltic Sea | 2003 | |
| Agarophyton vermiculophyllum | Denmark / North Sea | 2005 | |
| Agarophyton vermiculophyllum | France / Biscay Gulf | 2005 | |
| Agarophyton vermiculophyllum | France / Celtic seas | 1996 | |
| Agarophyton vermiculophyllum | France / English Channel | 1993 | |
| Agarophyton vermiculophyllum | Germany / Baltic Sea | 2005 | |
| Agarophyton vermiculophyllum | Germany / North Sea | 2002 | |
| Agarophyton vermiculophyllum | Ireland | 2012 | |
| 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 | |
| Alexandrium minutum | Denmark / Baltic Sea | 1992 | |
| Alexandrium minutum | Denmark / North Sea | 1998 | |
| Alexandrium minutum | France / Biscay Gulf | 1985 | |
| Alexandrium minutum | France / Celtic seas | 1985 | |
| Alexandrium minutum | France / English Channel | To 1988 | |
| Alexandrium minutum | France / North Sea | 1990 | |
| Alexandrium minutum | France / Western Mediterranean | 1988 | |
| Alexandrium minutum | Germany / Baltic Sea | To 1993 | |
| Alexandrium minutum | Germany / North Sea | 1990 - 1999 | |
| Alexandrium minutum | Netherlands | To 1992 | |
| Alexandrium minutum | Russia / Black Sea | 2000 | |
| Alexandrium minutum | Sweden / North Sea | To 1996 | |
| Alexandrium minutum | Turkey / Black Sea | 2002 - 2003 | |
| Alexandrium monilatum | Bulgaria | 1991 | |
| Alexandrium monilatum | Ukraine / Black Sea | 2001 | |
| Alexandrium ostenfeldii | Denmark / Baltic Sea | 1986 | |
| Alexandrium ostenfeldii | Denmark / North Sea | 1986 | |
| Alexandrium ostenfeldii | Netherlands | To 2018 | |
| Alexandrium ostenfeldii | Poland | 2001 | |
| Alexandrium ostenfeldii | Russia / Black Sea | 2004 | |
| Alexandrium pseudogonyaulax | Denmark / Baltic Sea | 2007 | |
| Alexandrium pseudogonyaulax | Denmark / North Sea | 2007 | |
| Alexandrium pseudogonyaulax | Germany / Baltic Sea | To 2010 | |
| Alexandrium pseudogonyaulax | Ukraine / Black Sea | From 2002 | |
| Alexandrium tamarense | Australia / Bass strait | 1993 | |
| Alexandrium tamarense | Bulgaria | 2008 | |
| Alexandrium tamarense | Denmark / Baltic Sea | 1983 | |
| Alexandrium tamarense | Denmark / North Sea | 1983 | |
| Alexandrium tamarense | Faroe Islands | To 2003 | |
| Alexandrium tamarense | France / Western Mediterranean | To 1998 | |
| Alexandrium tamarense | Germany / North Sea | To 1972 | |
| Alexandrium tamarense | Ireland | To 1986 | |
| Alexandrium tamarense | Netherlands | 1989 | |
| Alexandrium tamarense | Norway / North Sea | To 2001 | |
| Alexandrium tamarense | Romania | 2004 | |
| Alexandrium tamarense | Russia / Black Sea | 2004 | |
| Alexandrium tamarense | Turkey / Black Sea | 2007 - 2008 | |
| Alexandrium tamarense | Ukraine / Black Sea | From 2001 | |
| Alexandrium taylori | France / Biscay Gulf | 1994 | |
| Alexandrium taylori | France / Celtic seas | 1994 | |
| Aliculastrum cylindricum | Israel | 2002 | |
| Alitta succinea | Australia / Bass strait | 1978 | |
| Alitta succinea | Denmark / Baltic Sea | 1940 | |
| Alitta succinea | Denmark / North Sea | 1940 | |
| Alitta succinea | Germany / Baltic Sea | To 2016 | |
| Alitta succinea | United Kingdom (Britain) / North Sea | 1959 | |
| Alitta virens | Germany / Baltic Sea | 1920 | |
| Alitta virens | Germany / North Sea | 1923 | |
| Alitta virens | Netherlands | 1903 | |
| Alitta virens | United Kingdom (Britain) / Celtic seas | 1800 - 1900 | |
| Alitta virens | United Kingdom (Britain) / English Channel | 1800 - 1900 | |
| Alitta virens | United Kingdom (Britain) / North Sea | 1800 - 1900 | |
| Alkmaria romijni | Denmark / Baltic Sea | 1975 | |
| Alkmaria romijni | Denmark / North Sea | 1929 | |
| Alkmaria romijni | Netherlands | 1919 | |
| Alkmaria romijni | Norway / North Sea | To 1997 | |
| Alkmaria romijni | Russia / Baltic Sea / Kaliningrad area | 1996 | |
| Alkmaria romijni | Sweden / Baltic Sea | 1960 - 1972 | |
| Alloeocarpa loculosa | Portugal / Azores | To 1971 | |
| Allolepidapedon fistularia | Italy / Western Mediterranean | 2005 | |
| Allolepidapedon fistulariae | Israel | 2007 | |
| Alpheus dentipes | Bulgaria | 1966 | |
| Alpheus edwardsii | Israel | 1951 | |
| Alpheus lobidens | Israel | 1951 | |
| Alpheus migrans | Israel | 1977 | |
| Alpheus rapacida | Greece / Eastern Mediterranean | 1998 | |
| Alpheus rapacida | Israel | 1960 | |
| Alveinus miliaceus | Israel | 2016 | |
| Amathia distans | Australia / Bass strait | To 1999 | |
| Amathia gracilis | Germany / Baltic Sea | 1990 - 1999 | |
| Amathia gracilis | Germany / North Sea | 1990 - 1999 | |
| Amathia gracilis | Netherlands | To 1969 | |
| Amathia gracilis | United Kingdom (Britain) / Celtic seas / Channel Islands | 1960 - 1969 | |
| Amathia gracilis | United Kingdom (Britain) / English Channel | 2002 | |
| Amathia gracilis | United Kingdom (Britain) / North Sea | To 1996 | |
| Amathia imbricata | Germany / Baltic Sea | To 2015 | |
| Amathia imbricata | Germany / North Sea | To 2015 | |
| Amathia verticillata | France / Western Mediterranean | 2015 | |
| Amathia verticillata | Greece / Central Mediterranean | 1980 | |
| Amathia verticillata | Greece / Eastern Mediterranean | 1969 | |
| Amathia verticillata | Israel | 1960 | |
| Amathia verticillata | Italy / Adriatic Sea | To 1867 | |
| Amathia verticillata | Italy / Central Mediterranean | 1952 | |
| Amathia verticillata | Italy / Western Mediterranean | To 1822 | |
| Amathia verticillata | Portugal / Azores | 2009 | |
| Amathia verticillata | Portugal / Madeira | 2008 | |
| Amathia verticillata | Spain / Canary Islands | To 2011 | |
| Amathia verticillata | Spain / Iberian Coastal | To 2011 | |
| Amathia verticillata | Taiwan / South China Sea | 2015 | |
| Amathina tricarinata | Israel | 2004 | |
| Ameira divagans divagans | Germany / Baltic Sea | 1970 | |
| Ameira divagans divagans | Sweden / North Sea | | |
| Ammonia confertitesta | France / Biscay Gulf | 2019 | |
| Ammonia confertitesta | France / English Channel | 2019 | |
| Ammonia tepida | France / Biscay Gulf | 1970 | |
| Ammonia tepida | France / Celtic seas | 1970 | |
| Ammonia tepida | France / English Channel | 1970 | |
| Ammonia tepida | France / North Sea | 1970 | |
| Ammothea hilgendorfi | Belgium | 2013 | |
| Ammothea hilgendorfi | France / Biscay Gulf | 2019 | |
| Ammothea hilgendorfi | France / Western Mediterranean | 2019 | |
| Ammothea hilgendorfi | Italy / Adriatic Sea | 1979 | |
| Ammothea hilgendorfi | Netherlands | 2013 | |
| Ammothea hilgendorfi | United Kingdom (Britain) / English Channel | 1978 | |
| Ampelisca cavicoxa | Spain / Iberian Coastal | 2005 | |
| Ampelisca heterodactyla | Portugal / Iberian Coastal | To 1986 | |
| Ampelisca heterodactyla | Spain / Iberian Coastal | 1993 | |
| Amphiascus tenuiremis | Ukraine / Black Sea | From 1996 | |
| Amphibalanus amphitrite | Belgium | To 1952 | |
| Amphibalanus amphitrite | France / Biscay Gulf | 1914 | |
| Amphibalanus amphitrite | France / English Channel | 1928 | |
| Amphibalanus amphitrite | France / North Sea | 1982 | |
| Amphibalanus amphitrite | France / Western Mediterranean | 1973 | |
| Amphibalanus amphitrite | Germany / North Sea | To 2002 | |
| Amphibalanus amphitrite | Netherlands | 1962 | |
| Amphibalanus amphitrite | Portugal / Azores | To 1889 | |
| Amphibalanus amphitrite | Portugal / Iberian Coastal | 1982 | |
| Amphibalanus amphitrite | Portugal / Madeira | 2005 | |
| Amphibalanus amphitrite | Romania | 1844 | |
| Amphibalanus amphitrite | Spain / Iberian Coastal | To 2016 | |
| Amphibalanus amphitrite | Ukraine / Black Sea | 1905 | |
| Amphibalanus eburneus | Bulgaria | 1933 | |
| Amphibalanus eburneus | France / Biscay Gulf | 1872 | |
| Amphibalanus eburneus | France / Celtic seas | 1940 | |
| Amphibalanus eburneus | France / Western Mediterranean | 1973 | |
| Amphibalanus eburneus | Greece / Eastern Mediterranean | 1970 | |
| Amphibalanus eburneus | Iran / Caspian Sea | 2014 | |
| Amphibalanus eburneus | Italy / Adriatic Sea | From 1864 | |
| Amphibalanus eburneus | Italy / Central Mediterranean | To 1864 | |
| Amphibalanus eburneus | Italy / Western Mediterranean | From 1864 | |
| Amphibalanus eburneus | Japan / Sea of Japan | 1960 - 1969 | |
| Amphibalanus eburneus | Korea, Republic of / Sea of Japan | To 1992 | |
| Amphibalanus eburneus | Netherlands | 1890 - 1899 | |
| Amphibalanus eburneus | Portugal / Azores | To 1998 | |
| Amphibalanus eburneus | Russia / Caspian Sea | 1956 | |
| Amphibalanus eburneus | Spain / Iberian Coastal | To 2016 | |
| Amphibalanus eburneus | Turkey / Black Sea | 1968 | |
| Amphibalanus eburneus | Ukraine / Black Sea | From 1892 | |
| Amphibalanus improvisus | Belgium | To 1700 | |
| Amphibalanus improvisus | Bulgaria | 1844 | |
| Amphibalanus improvisus | Denmark / Baltic Sea | 1880 | |
| Amphibalanus improvisus | Denmark / North Sea | 1880 | |
| Amphibalanus improvisus | Estonia | 1801 - 1850 | |
| Amphibalanus improvisus | Finland | 1801 - 1860 | |
| Amphibalanus improvisus | France / Biscay Gulf | To 1901 | |
| Amphibalanus improvisus | France / Celtic seas | 1872 | |
| Amphibalanus improvisus | France / English Channel | To 1900 | |
| Amphibalanus improvisus | Georgia | 1978 - 1982 | |
| Amphibalanus improvisus | Germany / Baltic Sea | 1867 | |
| Amphibalanus improvisus | Germany / North Sea | 1858 | |
| Amphibalanus improvisus | Ireland | To 1950 | |
| Amphibalanus improvisus | Italy / Adriatic Sea | To 1951 | |
| Amphibalanus improvisus | Italy / Central Mediterranean | To 1942 | |
| Amphibalanus improvisus | Italy / Western Mediterranean | 1979 | |
| Amphibalanus improvisus | Latvia | 1801 - 1889 | |
| Amphibalanus improvisus | Lithuania | 1844 | |
| Amphibalanus improvisus | Netherlands | 1827 | |
| Amphibalanus improvisus | Norway / North Sea | 1800 - 1809 | |
| Amphibalanus improvisus | Norway / Norwegian Sea | 1800 - 1809 | |
| Amphibalanus improvisus | Poland | 1844 | |
| Amphibalanus improvisus | Portugal / Azores | 1887 | |
| Amphibalanus improvisus | Portugal / Iberian Coastal | 1974 | |
| Amphibalanus improvisus | Romania | 1844 | |
| Amphibalanus improvisus | Russia / Baltic Sea / Kaliningrad area | 1801 - 1889 | |
| Amphibalanus improvisus | Russia / Baltic Sea / St. Petersburg area | 1934 | |
| Amphibalanus improvisus | Spain / Iberian Coastal | 1900 | |
| Amphibalanus improvisus | Sweden / Baltic Sea | 1844 - 1899 | |
| Amphibalanus improvisus | Sweden / North Sea | 1844 - 1919 | |
| Amphibalanus improvisus | Turkey / Black Sea | 2005 | |
| Amphibalanus improvisus | Ukraine / Azov Sea | From 1844 | |
| Amphibalanus improvisus | Ukraine / Black Sea | From 1844 | |
| Amphibalanus improvisus | United Kingdom (Britain) / Celtic seas | 1854 | |
| Amphibalanus improvisus | United Kingdom (Britain) / North Sea | 1500 - 1854 | |
| Amphibalanus reticulatus | Belgium | 1997 | |
| Amphibalanus reticulatus | France / English Channel | 2001 | |
| Amphibalanus reticulatus | France / North Sea | 2001 | |
| Amphibalanus reticulatus | France / Western Mediterranean | 1977 | |
| Amphibalanus reticulatus | Israel | 2003 | |
| Amphibalanus variegatus | Belgium | 1997 | |
| Amphibalanus variegatus | France / English Channel | 1997 | |
| Amphibalanus variegatus | France / North Sea | 1997 | |
| Amphicorina pectinata | Spain / Iberian Coastal | To 2017 | |
| Amphioctopus aegina | Israel | 1934 | |
| Amphiroa rigida | Turkey / Black Sea | 1990 - 1999 | |
| Amphisbetia operculata | Australia / Bass strait | 1884 | |
| Amphisorus hemprichii | Italy / Central Mediterranean | 2005 | |
| Amphistegina lessonii | Italy / Central Mediterranean | 2005 | |
| Amphistegina lobifera | Greece / Central Mediterranean | 1955 - 1961 | |
| Amphistegina lobifera | Greece / Eastern Mediterranean | 1955 - 1961 | |
| Amphistegina lobifera | Italy / Central Mediterranean | 2005 | |
| Amphiura parviscutata | Australia / Bass strait | 1966 | |
| Amphogona pusilla | Italy / Western Mediterranean | 1972 | |
| Amphorellopsis acuta | Russia / Black Sea | 2010 | |
| Amphorellopsis acuta | Ukraine / Black Sea | 2011 | |
| Ampithoe valida | France / Biscay Gulf | 2014 | |
| Ampithoe valida | Netherlands | To 2013 | |
| Ampithoe valida | Portugal / Iberian Coastal | 1993 | |
| Anadara diluvii | Spain / Iberian Coastal | 1996 | |
| Anadara inaequivalvis | Bulgaria | 1982 | |
| Anadara inaequivalvis | Georgia | 1978 | |
| Anadara inaequivalvis | Romania | 1984 | |
| Anadara inaequivalvis | Russia / Azov Sea | 1989 | |
| Anadara inaequivalvis | Russia / Black Sea | 1980 - 1990 | |
| Anadara inaequivalvis | Turkey / Black Sea | 1980 - 1990 | |
| Anadara inaequivalvis | Ukraine / Azov Sea | From 1987 | |
| Anadara inaequivalvis | Ukraine / Black Sea | From 1987 | |
| Anadara kagoshimensis | Italy / Adriatic Sea | 1969 | |
| Anadara kagoshimensis | Spain / Iberian Coastal | 1993 - 1994 | |
| Anadara kagoshimensis | Turkey / Black Sea | 2003 | |
| Anadara natalensis | Israel | 1935 | |
| Anadara transversa | Greece / Eastern Mediterranean | 1993 | |
| Anadara transversa | Italy / Adriatic Sea | 1970 - 1980 | |
| Anadara transversa | Italy / Central Mediterranean | 2007 | |
| Anadara transversa | Italy / Western Mediterranean | 2005 | |
| Angiola punctostriata | Israel | 1950 | |
| Anguillicoloides crassus | Belgium | To 1989 | |
| Anguillicoloides crassus | Denmark / Baltic Sea | 1987 - 1989 | |
| Anguillicoloides crassus | Denmark / North Sea | To 1985 | |
| Anguillicoloides crassus | Estonia | 1989 | |
| Anguillicoloides crassus | Finland | 2002 | |
| Anguillicoloides crassus | France / Biscay Gulf | 1980 | |
| Anguillicoloides crassus | France / English Channel | 1980 | |
| Anguillicoloides crassus | France / North Sea | 1980 | |
| Anguillicoloides crassus | Germany / Baltic Sea | 1960 - 1987 | |
| Anguillicoloides crassus | Germany / North Sea | 1982 | |
| Anguillicoloides crassus | Ireland | 1998 | |
| Anguillicoloides crassus | Italy / Adriatic Sea | 1997 | |
| Anguillicoloides crassus | Italy / Western Mediterranean | 2001 - 2011 | |
| Anguillicoloides crassus | Latvia | 1998 | |
| Anguillicoloides crassus | Lithuania | 1998 | |
| Anguillicoloides crassus | Netherlands | To 1985 | |
| Anguillicoloides crassus | Norway / North Sea | 1994 | |
| Anguillicoloides crassus | Poland | 1988 | |
| Anguillicoloides crassus | Portugal / Iberian Coastal | 1992 | |
| Anguillicoloides crassus | Russia / Baltic Sea / Kaliningrad area | 1988 | |
| Anguillicoloides crassus | Sweden / Baltic Sea | 1987 | |
| Anguillicoloides crassus | Sweden / North Sea | 1989 | |
| Anguillicoloides crassus | United Kingdom (Britain) / English Channel | From 1987 | |
| Anguillicoloides crassus | United Kingdom (Britain) / North Sea | 1987 | |
| Anomia chinensis | France / Biscay Gulf | 1971 | |
| Anomia chinensis | France / Celtic seas | 1974 | |
| Anomia ephippium | Netherlands | 1935 | |
| Anoplodactylus californicus | Israel | 1951 | |
| Anoplodactylus californicus | Italy / Western Mediterranean | 1965 | |
| Anoplodactylus digitatus | Israel | 1951 | |
| Anotrichium furcellatum | France / Celtic seas | 1922 | |
| Anotrichium furcellatum | France / English Channel | To 1922 | |
| Anotrichium furcellatum | Greece / Eastern Mediterranean | 1971 - 1973 | |
| Anotrichium furcellatum | Israel | 1958 | |
| Anotrichium furcellatum | Netherlands | 1950 | |
| Anotrichium furcellatum | Portugal / Azores | 2005 - 2007 | |
| Anotrichium furcellatum | Portugal / Iberian Coastal | To 1960 | |
| Anotrichium furcellatum | Portugal / Madeira | 1970 | |
| Anotrichium furcellatum | Spain / Canary Islands | To 2004 | |
| Anotrichium furcellatum | Spain / Iberian Coastal | 1979 | |
| Antennella secundaria | Australia / Bass strait | 1910 | |
| Anthopleura anjunae | Spain / Iberian Coastal | To 2016 | |
| Anthopleura elegantissima | Spain / Iberian Coastal | To 2016 | |
| Antithamnion amphigeneum | France / Western Mediterranean | To 1998 | |
| Antithamnion amphigeneum | Italy / Central Mediterranean | 2005 | |
| Antithamnion amphigeneum | Italy / Western Mediterranean | 1996 | |
| Antithamnion amphigeneum | Portugal / Iberian Coastal | To 2004 | |
| Antithamnion amphigeneum | Spain / Iberian Coastal | 1995 | |
| Antithamnion densum | France / Biscay Gulf | 1964 | |
| Antithamnion densum | France / Celtic seas | 1964 | |
| Antithamnion densum | France / English Channel | 1964 | |
| Antithamnion densum | France / North Sea | 1981 | |
| Antithamnion densum | Ireland | 1991 | |
| Antithamnion densum | Portugal / Azores | 2005 | |
| Antithamnion densum | Portugal / Iberian Coastal | 2004 | |
| Antithamnion densum | Spain / Canary Islands | To 2006 | |
| Antithamnion densum | Spain / Iberian Coastal | 1984 - 1995 | |
| Antithamnion diminuatum | Portugal / Azores | 1989 | |
| Antithamnion diminuatum | Spain / Canary Islands | To 1996 | |
| Antithamnion hubbsii | France / Biscay Gulf | 2011 | |
| Antithamnion hubbsii | France / English Channel | 2018 | |
| Antithamnion hubbsii | France / Western Mediterranean | 1988 | |
| Antithamnion hubbsii | Norway / North Sea | To 2007 | |
| Antithamnion nipponicum | Italy / Adriatic Sea | 1994 | |
| Antithamnion nipponicum | Norway / North Sea | 2007 | |
| Antithamnion nipponicum | Portugal / Azores | 1989 | |
| Antithamnion nipponicum | Portugal / Iberian Coastal | From 2008 | |
| Antithamnion nipponicum | United Kingdom (Britain) / North Sea / Orkney Islands | 2020 | |
| Antithamnion pectinatum | France / Western Mediterranean | 1983 | |
| Antithamnion pectinatum | Portugal / Azores | To 1994 | |
| Antithamnion pectinatum | Portugal / Iberian Coastal | To 2008 | |
| Antithamnionella boergesenii | France / Western Mediterranean | 1995 | |
| Antithamnionella boergesenii | Italy / Central Mediterranean | 1991 - 1992 | |
| Antithamnionella boergesenii | Portugal / Azores | 2005 - 2007 | |
| Antithamnionella boergesenii | Portugal / Madeira | From 2001 | |
| Antithamnionella elegans | Greece / Central Mediterranean | 1975 | |
| Antithamnionella elegans | Greece / Eastern Mediterranean | 2007 | |
| Antithamnionella elegans | Italy / Adriatic Sea | 1980 - 1984 | |
| Antithamnionella elegans | Italy / Central Mediterranean | 1970 - 1971 | |
| Antithamnionella elegans | Italy / Western Mediterranean | 1822 | |
| Antithamnionella elegans var. sublittoralis | Italy / Central Mediterranean | 1980 | |
| Antithamnionella spirographidis | Australia / Bass strait | 1976 | |
| Antithamnionella spirographidis | Belgium | 1992 | |
| Antithamnionella spirographidis | France / Biscay Gulf | 1975 | |
| Antithamnionella spirographidis | France / Celtic seas | 1911 | |
| Antithamnionella spirographidis | France / English Channel | 1927 | |
| Antithamnionella spirographidis | France / Western Mediterranean | 2004 | |
| Antithamnionella spirographidis | Germany / North Sea | 2012 | |
| Antithamnionella spirographidis | Greece / Central Mediterranean | 1983 | |
| Antithamnionella spirographidis | Greece / Eastern Mediterranean | 1992 | |
| Antithamnionella spirographidis | Ireland | 1969 | |
| Antithamnionella spirographidis | Italy / Adriatic Sea | 1995 | |
| Antithamnionella spirographidis | Netherlands | 1974 | |
| Antithamnionella spirographidis | Portugal / Iberian Coastal | 2003 - 2008 | |
| Antithamnionella spirographidis | Portugal / Madeira | To 1974 | |
| Antithamnionella spirographidis | Spain / Iberian Coastal | 1927 | |
| Antithamnionella spirographidis | United Kingdom (Britain) / English Channel | To 1911 | |
| Antithamnionella ternifolia | Australia / Bass strait | 1977 | |
| Antithamnionella ternifolia | Belgium | 1970 | |
| Antithamnionella ternifolia | Denmark / Baltic Sea | 2014 | |
| Antithamnionella ternifolia | France / Biscay Gulf | 1969 | |
| Antithamnionella ternifolia | France / Celtic seas | 1910 | |
| Antithamnionella ternifolia | France / English Channel | 1910 | |
| Antithamnionella ternifolia | France / Western Mediterranean | 1981 | |
| Antithamnionella ternifolia | Germany / Baltic Sea | 2014 | |
| Antithamnionella ternifolia | Germany / North Sea | 1958 | |
| Antithamnionella ternifolia | Ireland | 1930 | |
| Antithamnionella ternifolia | Netherlands | 1951 | |
| Antithamnionella ternifolia | New Zealand / New Zealand Shelf / North Island | To 1972 | |
| Antithamnionella ternifolia | New Zealand / New Zealand Shelf / South Island | To 1904 | |
| Antithamnionella ternifolia | Portugal / Azores | 1987 | |
| Antithamnionella ternifolia | Portugal / Iberian Coastal | 1958 | |
| Antithamnionella ternifolia | Spain / Iberian Coastal | 1920 - 1929 | |
| Antithamnionella ternifolia | United Kingdom (Britain) / English Channel | To 1906 | |
| Antithamnionella ternifolia | United Kingdom (Britain) / North Sea | To 1999 | |
| Aoroides curvipes | France / Biscay Gulf | 2009 | |
| Aoroides longimerus | France / Biscay Gulf | 2013 | |
| Aoroides longimerus | France / Celtic seas | 2014 | |
| Aoroides longimerus | France / English Channel | 2014 | |
| Aoroides longimerus | France / Western Mediterranean | From 2015 | |
| Aoroides secundus | France / Biscay Gulf | To 2010 | |
| Aoroides semicurvatus | France / Biscay Gulf | 2009 | |
| Aoroides semicurvatus | France / English Channel | 2019 | |
| Aoroides semicurvatus | Netherlands | 2017 | |
| Apedinella radians | Bulgaria | 1987 | |
| Apedinella radians | Romania | 1991 | |
| Apedinella radians | Ukraine / Black Sea | From 1999 | |
| Aphanius dispar | Israel | 1944 | |
| Aphelochaeta marioni | Denmark / Baltic Sea | 1991 | |
| Aphelochaeta marioni | Denmark / North Sea | 1984 | |
| Aphelochaeta marioni | France / English Channel | 2001 | |
| Aphelochaeta marioni | Germany / North Sea | 1938 | |
| Aphelochaeta marioni | Netherlands | To 1951 | |
| Aphelochaeta marioni | United Kingdom (Britain) / North Sea / Orkney Islands | 1997 | |
| Aplidium accarense | Italy / Central Mediterranean | 2018 | |
| Aplidium accarense | Italy / Western Mediterranean | To 2015 | |
| Aplidium glabrum | Belgium | To 2018 | |
| Aplidium glabrum | Germany / North Sea | 1992 | |
| Aplidium glabrum | Ireland | 2010 | |
| Aplidium glabrum | Netherlands | To 1977 | |
| Aplidium glabrum | Portugal / Madeira | 2013 | |
| Aplidium pallidum | Italy / Western Mediterranean | 1913 | |
| Aplysia dactylomela | Greece / Central Mediterranean | 2005 | |
| Aplysia dactylomela | Greece / Eastern Mediterranean | 2005 | |
| Aplysia dactylomela | Portugal / Madeira | From 1987 | |
| Aplysilla rosea | Australia / Bass strait | 1981 | |
| Aplysiopsis formosa | Australia / Bass strait | 1994 | |
| Apoglossum gregarium | France / Western Mediterranean | To 1996 | |
| Apoglossum gregarium | Italy / Central Mediterranean | 1999 | |
| Apoglossum gregarium | Italy / Western Mediterranean | 1992 | |
| Apogonichthyoides pharaonis | Greece / Eastern Mediterranean | 1982 | |
| Apogonichthyoides pharaonis | Israel | 1947 | |
| Aporrhais pespelecani | Georgia | 1960 | |
| Aporrhais pespelecani | Turkey / Black Sea | 1896 | |
| Aporrhais pespelecani | Ukraine / Black Sea | From 1987 | |
| Apseudopsis tridens | Italy / Adriatic Sea | 2019 | |
| Aquilonastra burtoni | Israel | 1955 | |
| Arachnidium lacourti | Germany / Baltic Sea | To 2015 | |
| Arachnidium lacourti | Germany / North Sea | 2014 | |
| Arachnidium lacourti | Netherlands | To 2005 | |
| Arachnoidea protecta | Italy / Western Mediterranean | 1992 | |
| Arbopercula tenella | Israel | 2012 | |
| Arbopercula tenella | Italy / Central Mediterranean | 1990 | |
| Arbopercula tenella | Italy / Western Mediterranean | To 2011 | |
| Arcania brevifrons | Israel | 2016 | |
| Archesola typhlops | Ukraine / Black Sea | 2007 | |
| Arcuatula perfragilis | Israel | 1960 | |
| Arcuatula senhousia | Australia / Bass strait | 1980 - 1989 | |
| Arcuatula senhousia | France / Biscay Gulf | 1971 | |
| Arcuatula senhousia | France / Celtic seas | To 2008 | |
| Arcuatula senhousia | France / North Sea | 2018 | |
| Arcuatula senhousia | France / Western Mediterranean | 1982 | |
| Arcuatula senhousia | Israel | 1960 | |
| Arcuatula senhousia | Italy / Adriatic Sea | 1994 | |
| Arcuatula senhousia | Italy / Central Mediterranean | 2001 | |
| Arcuatula senhousia | Italy / Western Mediterranean | 1999 | |
| Arcuatula senhousia | Romania | 2002 | |
| Arcuatula senhousia | Spain / Iberian Coastal | To 2012 | |
| Argopecten irradians | China / Yellow Sea | 1982 | |
| Argopecten irradians | Korea, Democratic Peoples Republic of / Sea of Japan | To 2013 | |
| Argopecten irradians | Korea, Republic of / Sea of Japan | To 2013 | |
| Aricidea hartmani | Canada / Hudson Bay Complex | To 2010 | |
| Arietellus pavoninus | Greece / Eastern Mediterranean | 1967 | |
| Arnoglossus nigrofilamentosus | Israel | 2017 | |
| Artemia franciscana | France / Biscay Gulf | 1800 - 1899 | |
| Artemia franciscana | Italy / Adriatic Sea | 2004 | |
| Artemia franciscana | Portugal / Iberian Coastal | To 1980 | |
| Artemia franciscana | Portugal / Madeira | 1997 | |
| Artemia franciscana | Spain / Iberian Coastal | To 2002 | |
| Ascidia cannelata | Israel | 1955 | |
| Ascidia interrupta | Portugal / Azores | To 1992 | |
| Ascidiella aspersa | Australia / Bass strait | To 1985 | |
| Ascidiella aspersa | Canada / South-eastern Scotian Shelf | 2012 | |
| Ascidiella aspersa | Greece / Eastern Mediterranean | 1901 | |
| Ascidiella aspersa | Iceland | 2018 | |
| Ascidiella aspersa | Portugal / Madeira | 2015 | |
| Ascidiella aspersa | United Kingdom (Britain) / North Sea / Orkney Islands | 1994 | |
| Ascidiella scabra | Iceland | 2020 | |
| Ascidiella scabra | United Kingdom (Britain) / North Sea / Orkney Islands | 1994 | |
| Ascophyllum nodosum | Italy / Central Mediterranean | 2009 | |
| Ashtoret lunaris | Israel | 1987 | |
| Asparagopsis armata | France / Biscay Gulf | 1925 | |
| Asparagopsis armata | France / Celtic seas | 1922 | |
| Asparagopsis armata | France / English Channel | 1999 | |
| Asparagopsis armata | France / Western Mediterranean | 1926 | |
| Asparagopsis armata | Greece / Central Mediterranean | 2010 | |
| Asparagopsis armata | Greece / Eastern Mediterranean | 2010 | |
| Asparagopsis armata | Ireland | 1939 | |
| Asparagopsis armata | Italy / Adriatic Sea | To 1978 | |
| Asparagopsis armata | Italy / Central Mediterranean | To 1972 | |
| Asparagopsis armata | Italy / Western Mediterranean | To 1955 | |
| Asparagopsis armata | Netherlands | To 1983 | |
| Asparagopsis armata | Portugal / Azores | 1989 | |
| Asparagopsis armata | Portugal / Iberian Coastal | 1951 | |
| Asparagopsis armata | Portugal / Madeira | To 1974 | |
| Asparagopsis armata | Spain / Canary Islands | To 1980 | |
| Asparagopsis armata | Spain / Iberian Coastal | 1933 | |
| Asparagopsis armata | Turkey / Black Sea | 1973 | |
| Asparagopsis armata | United Kingdom (Britain) / Celtic seas / Channel Islands | 1949 | |
| Asparagopsis armata | United Kingdom (Britain) / English Channel | 1949 - 1950 | |
| Asparagopsis armata | United Kingdom (Britain) / North Sea | 1973 | |
| Asparagopsis armata | United Kingdom (Britain) / North Sea / Orkney Islands | From 1960 | |
| Asparagopsis taxiformis | France / Western Mediterranean | To 2006 | |
| Asparagopsis taxiformis | Portugal / Azores | 1929 | |
| Asparagopsis taxiformis | Portugal / Iberian Coastal | To 2000 | |
| Asparagopsis taxiformis | Portugal / Madeira | 1970 | |
| Asparagopsis taxiformis lineage 2 | Greece / Adriatic Sea | 2013 | |
| Asparagopsis taxiformis lineage 2 | Greece / Central Mediterranean | 2006 | |
| Asparagopsis taxiformis lineage 2 | Greece / Eastern Mediterranean | 1992 | |
| Asparagopsis taxiformis lineage 2 | Italy / Central Mediterranean | 1992 | |
| Asparagopsis taxiformis lineage 2 | Italy / Western Mediterranean | 1993 | |
| Asperococcus ensiformis | Australia / Bass strait | 1976 | |
| Asperococcus scaber | Netherlands | 1998 | |
| Aspidosiphon mexicanus | Greece / Central Mediterranean | 1994 | |
| Aspidosiphon mexicanus | Greece / Eastern Mediterranean | 1991 | |
| Asterias amurensis | Australia / Bass strait | 1995 | |
| Asterias rubens | Turkey / Black Sea | 2003 | |
| Asterionellopsis glacialis | Netherlands | To 2018 | |
| Asterionellopsis glacialis | Romania | 1968 | |
| Asterionellopsis glacialis | Russia / Black Sea | 1998 | |
| Asterionellopsis glacialis | Ukraine / Black Sea | From 1967 | |
| Asterocarpa humilis | France / Biscay Gulf | To 2013 | |
| Asterocarpa humilis | France / English Channel | 2005 | |
| Asterocarpa humilis | United Kingdom (Britain) / Celtic seas | 2013 | |
| Asterocarpa humilis | United Kingdom (Britain) / North Sea / Orkney Islands | 2014 | |
| Asteromphalus sarcophagus | France / Biscay Gulf | To 2003 | |
| Asteromphalus sarcophagus | France / Celtic seas | 2003 | |
| Asteromphalus sarcophagus | France / English Channel | 2001 | |
| Asthenognathus atlanticus | France / English Channel | 2008 | |
| Asthenognathus atlanticus | Netherlands | 2019 | |
| Atergatis roseus | Greece / Eastern Mediterranean | 2009 | |
| Atergatis roseus | Israel | 1961 | |
| Atherina boyeri | Netherlands | To 1964 | |
| Atherina boyeri | United Kingdom (Britain) / Celtic seas | 1956 | |
| Atherinomorus forskalii | Greece / Central Mediterranean | 2012 | |
| Atherinomorus forskalii | Greece / Eastern Mediterranean | 1986 | |
| Atherinomorus forskalii | Israel | 1924 | |
| Atrina rigida | United Kingdom (Britain) / English Channel | 1986 | |
| Attheya armata | United Kingdom (Britain) / Celtic seas | 2000 | |
| Attheya decora | Ukraine / Black Sea | 2000 | |
| Atyaephyra desmaresti | Belgium | To 1895 | |
| Atyaephyra desmaresti | Germany / North Sea | 1932 | |
| Atys angustatus | Israel | 1974 | |
| Aurelia aurita | Russia / Caspian Sea | 1999 | |
| Aurelia coerulea | France / Western Mediterranean | 2002 | |
| Aurelia coerulea | Italy / Adriatic Sea | 2011 | |
| Aurelia coerulea | Italy / Western Mediterranean | To 2016 | |
| Aurelia solida | France / Western Mediterranean | 2002 | |
| Aurelia solida | Italy / Adriatic Sea | 2005 - 2010 | |
| Aurelia solida | Italy / Central Mediterranean | 2013 | |
| Auriculinella bidentata | Germany / North Sea | 1997 | |
| Austrominius modestus | Belgium | 1950 | |
| Austrominius modestus | Denmark / North Sea | 1978 | |
| Austrominius modestus | France / Biscay Gulf | 1953 | |
| Austrominius modestus | France / Celtic seas | 1953 | |
| Austrominius modestus | France / English Channel | 1953 | |
| Austrominius modestus | France / North Sea | 1950 | |
| Austrominius modestus | France / Western Mediterranean | 1990 - 1999 | |
| Austrominius modestus | Germany / North Sea | 1953 | |
| Austrominius modestus | Ireland | 1957 | |
| Austrominius modestus | Netherlands | 1946 | |
| Austrominius modestus | Portugal / Iberian Coastal | From 1956 | |
| Austrominius modestus | Portugal / Madeira | To 2005 | |
| Austrominius modestus | Spain / Iberian Coastal | To 2006 | |
| Austrominius modestus | Sweden / North Sea | | |
| Austrominius modestus | United Kingdom (Britain) / English Channel | 1940 - 1945 | |
| Austrominius modestus | United Kingdom (Britain) / North Sea | From 1945 | |
| Austrominius modestus | United Kingdom (Britain) / North Sea / Orkney Islands | To 2017 | |
| Autonoe spiniventris | Spain / Iberian Coastal | To 2005 | |
| Axionice medusa | Greece / Central Mediterranean | 1980 | |
| Axionice medusa | Greece / Eastern Mediterranean | 1975 | |
| Axionice medusa | Italy / Central Mediterranean | 1985 | |
| Azadinium spinosum | Bulgaria | 2005 | |
| Azolla caroliniana | Ukraine / Black Sea | 1970 - 1979 | |
| Azolla filiculoides | Ireland | From 1907 | |
| Azolla filiculoides | Ukraine / Black Sea | 1970 - 1979 | |
