| Species |
Recipient region |
Date of the first record |
|
| Calanopia elliptica | Greece / Eastern Mediterranean | 1988 |  |
| Calanopia elliptica | Israel | 1963 | |
| Calanopia elliptica | Italy / Western Mediterranean | To 1892 | |
| Calanus euxinus | Russia / Caspian Sea | 2004 | |
| Calappa pelii | Greece / Central Mediterranean | 2005 | |
| Calappa pelii | Greece / Eastern Mediterranean | 2005 | |
| Caligus pageti | Ireland | 1986 | |
| Calliblepharis rammediorum | Israel | 2013 | |
| Callinectes danae | Italy / Adriatic Sea | 1981 | |
| Callinectes sapidus | Belgium | 1981 | |
| Callinectes sapidus | Bulgaria | 1967 | |
| Callinectes sapidus | Denmark / Baltic Sea | 1951 | |
| Callinectes sapidus | Denmark / North Sea | 1951 | |
| Callinectes sapidus | France / Biscay Gulf | 1901 | |
| Callinectes sapidus | France / Celtic seas | 1901 | |
| Callinectes sapidus | France / Western Mediterranean | To 1962 | |
| Callinectes sapidus | Georgia | 1975 | |
| Callinectes sapidus | Germany / Baltic Sea | 2023 | |
| Callinectes sapidus | Germany / North Sea | 1964 | |
| Callinectes sapidus | Greece / Adriatic Sea | 2013 | |
| Callinectes sapidus | Greece / Central Mediterranean | 1990 - 1999 | |
| Callinectes sapidus | Greece / Eastern Mediterranean | 1947 | |
| Callinectes sapidus | Israel | 1955 | |
| Callinectes sapidus | Italy / Adriatic Sea | 1949 | |
| Callinectes sapidus | Italy / Central Mediterranean | 1970 | |
| Callinectes sapidus | Italy / Western Mediterranean | 1962 | |
| Callinectes sapidus | Netherlands | 1932 | |
| Callinectes sapidus | Poland | 2018 | |
| Callinectes sapidus | Portugal / Iberian Coastal | 1978 | |
| Callinectes sapidus | Romania | 1998 | |
| Callinectes sapidus | Russia / Azov Sea | 1967 | |
| Callinectes sapidus | Russia / Black Sea | 1970 - 1979 | |
| Callinectes sapidus | Spain / Iberian Coastal | 2004 | |
| Callinectes sapidus | Turkey / Black Sea | From 1974 | |
| Callinectes sapidus | Ukraine / Azov Sea | 1970 - 1979 | |
| Callinectes sapidus | Ukraine / Black Sea | 1970 - 1979 | |
| Callinectes sapidus | United Kingdom (Britain) / North Sea | 1982 | |
| Callionymus filamentosus | Greece / Central Mediterranean | 2016 | |
| Callionymus filamentosus | Greece / Eastern Mediterranean | 2003 | |
| Callionymus filamentosus | Israel | 1953 | |
| Calliostoma zizyphinum | Netherlands | 2001 | |
| Callyspongia (Callyspongia) siphonella | Spain / Iberian Coastal | To 2016 | |
| Callyspongia pergamentacea | Australia / Bass strait | 1895 | |
| Calocalanus plumulosus | Romania | 1978 | |
| Caloria indica | Israel | 1986 | |
| Calyptospadix cerulea | Germany / North Sea | 2021 | |
| Calyptraea chinensis | France / English Channel | To 1977 | |
| Calyptraea chinensis | France / North Sea | To 1976 | |
| Calyptraea chinensis | Ireland | 1949 - 1956 | |
| Calyptraea chinensis | Netherlands | To 1942 | |
| Calyptraea chinensis | United Kingdom (Britain) / Celtic seas | 1957 | |
| Campanularia morgansi | Israel | 2009 | |
| Canarium mutabile | Israel | 1991 | |
| Cancer irroratus | Iceland | 2006 | |
| Cancer irroratus | Sweden / North Sea | 2019 | |
| Caprella equilibra | Australia / Bass strait | 1885 | |
| Caprella mutica | Belgium | 1998 | |
| Caprella mutica | Canada / Bay of Fundy | 2002 | |
| Caprella mutica | Canada / Northern Gulf of St. Lawrence | 2016 | |
| Caprella mutica | Canada / Northern Newfoundland | 2012 | |
| Caprella mutica | Canada / South-eastern Scotian Shelf | 2003 | |
| Caprella mutica | Canada / Southern Gulf of St. Lawrence and Eastern Scotian Shelf | 1998 | |
| Caprella mutica | Canada / Southern Newfoundland and Southern Grand Banks | 2010 | |
| Caprella mutica | Denmark / Baltic Sea | 2017 | |
| Caprella mutica | Denmark / North Sea | 2005 | |
| Caprella mutica | France / Biscay Gulf | 2004 | |
| Caprella mutica | France / North Sea | 2004 | |
| Caprella mutica | Germany / North Sea | 2004 | |
| Caprella mutica | Ireland | 2003 | |
| Caprella mutica | Netherlands | 1993 | |
| Caprella mutica | Norway / North Sea | 1999 | |
| Caprella mutica | Norway / Norwegian Sea | To 2012 | |
| Caprella mutica | Spain / Iberian Coastal | 2012 - 2013 | |
| Caprella mutica | Sweden / North Sea | 2011 | |
| Caprella mutica | United Kingdom (Britain) / Celtic seas | 2000 | |
| Caprella mutica | United Kingdom (Britain) / English Channel | 2000 | |
| Caprella mutica | United Kingdom (Britain) / North Sea | 2002 | |
| Caprella mutica | United Kingdom (Britain) / North Sea / Orkney Islands | To 2006 | |
| Caprella penantis | Australia / Bass strait | 1975 | |
| Caprella scaura | Australia / Bass strait | 1971 | |
| Caprella scaura | France / Western Mediterranean | 2014 | |
| Caprella scaura | Greece / Central Mediterranean | 2002 | |
| Caprella scaura | Greece / Eastern Mediterranean | 2012 | |
| Caprella scaura | Italy / Adriatic Sea | 1994 | |
| Caprella scaura | Italy / Central Mediterranean | 1989 - 1990 | |
| Caprella scaura | Italy / Western Mediterranean | 2003 - 2004 | |
| Caprella scaura | Netherlands | To 2016 | |
| Caprella scaura | Portugal / Azores | 2015 | |
| Caprella scaura | Portugal / Iberian Coastal | To 1985 | |
| Caprella scaura | Portugal / Madeira | To 2014 | |
| Caprella scaura | Spain / Canary Islands | 2009 | |
| Caprella scaura | Spain / Iberian Coastal | To 2011 | |
| Carassius auratus | Denmark / Baltic Sea | 1990 | |
| Carassius auratus | Denmark / North Sea | 2012 | |
| Carassius gibelio | Estonia | 1948 | |
| Carassius gibelio | Finland | 2001 - 2005 | |
| Carassius gibelio | Latvia | 1948 | |
| Carassius gibelio | Lithuania | 1601 - 1700 | |
| Carassius gibelio | Poland | 1930 - 1933 | |
| Carassius gibelio | Russia / Baltic Sea / St. Petersburg area | 2005 | |
| Carassius gibelio | Sweden / Baltic Sea | 1800 - 1997 | |
| Carbosphaerella leptosphaerioides | Ukraine / Black Sea | 1991 | |
| Carcinus maenas | Australia / Bass strait | 1802 - 1851 | |
| Carcinus maenas | Canada / Bay of Fundy | 1951 | |
| Carcinus maenas | Canada / Northern Gulf of St. Lawrence | 2008 | |
| Carcinus maenas | Canada / South-eastern Scotian Shelf | 1954 | |
| Carcinus maenas | Canada / Southern Gulf of St. Lawrence and Eastern Scotian Shelf | 1994 | |
| Carcinus maenas | Canada / Southern Newfoundland and Southern Grand Banks | 2007 | |
| Carpobrotus acinaciformis | Spain / Iberian Coastal | To 1900 | |
| Carupa tenuipes | Greece / Eastern Mediterranean | 2009 | |
| Carupa tenuipes | Israel | 2002 | |
| Cassiopea andromeda | Greece / Central Mediterranean | 2018 | |
| Cassiopea andromeda | Greece / Eastern Mediterranean | 1942 | |
| Cassiopea andromeda | Israel | 1988 | |
| Cassiopea andromeda | Italy / Western Mediterranean | 2014 | |
| Catostomus catostomus | Finland | 1980 - 1984 | |
| Catostomus catostomus | Russia / Baltic Sea / St. Petersburg area | 1980 - 1984 | |
| Caulacanthus okamurae | Italy / Adriatic Sea | 2018 - 2020 | |
| Caulacanthus okamurae | Italy / Central Mediterranean | 2018 | |
| Caulacanthus okamurae | Netherlands | 2018 | |
| Caulacanthus ustulatus | Belgium | To 2011 | |
| Caulacanthus ustulatus | France / Biscay Gulf | 2005 | |
| Caulacanthus ustulatus | France / Celtic seas | 1986 | |
| Caulacanthus ustulatus | France / English Channel | 1986 | |
| Caulacanthus ustulatus | Netherlands | To 2018 | |
| Caulacanthus ustulatus | Portugal / Azores | 1897 | |
| Caulacanthus ustulatus | United Kingdom (Britain) / English Channel | 2004 | |
| Caulerpa cylindracea | France / Western Mediterranean | 1997 | |
| Caulerpa cylindracea | Greece / Adriatic Sea | 2013 | |
| Caulerpa cylindracea | Greece / Central Mediterranean | 1993 | |
| Caulerpa cylindracea | Greece / Eastern Mediterranean | 1996 | |
| Caulerpa cylindracea | Italy / Adriatic Sea | 2000 | |
| Caulerpa cylindracea | Italy / Central Mediterranean | 1993 | |
| Caulerpa cylindracea | Italy / Western Mediterranean | 1994 | |
| Caulerpa cylindracea | Spain / Canary Islands | To 1989 | |
| Caulerpa denticulata | Israel | 1929 | |
| Caulerpa mexicana | Israel | 1939 | |
| Caulerpa racemosa var. lamourouxii f. requienii | Greece / Central Mediterranean | 2009 | |
| Caulerpa racemosa var. lamourouxii f. requienii | Greece / Eastern Mediterranean | 1956 | |
| Caulerpa racemosa var. lamourouxii f. requienii | Israel | 1951 | |
| Caulerpa taxifolia | France / Western Mediterranean | 1984 - 1987 | |
| Caulerpa taxifolia | Italy / Central Mediterranean | 1993 | |
| Caulerpa taxifolia | Italy / Western Mediterranean | 1992 | |
| Caulerpa taxifolia var. distichophylla | Greece / Eastern Mediterranean | 2010 | |
| Caulerpa taxifolia var. distichophylla | Israel | 2019 | |
| Caulerpa taxifolia var. distichophylla | Italy / Central Mediterranean | 2008 | |
| Caulerpa taxifolia var. distichophylla | Italy / Western Mediterranean | 2012 | |
| Caulerpa webbiana | Portugal / Azores | 2002 | |
| Caulerpa webbiana | Portugal / Madeira | From 1974 | |
| Caulibugula arcasounensis | France / Biscay Gulf | 2001 | |
| Caulibugula zanzibariensis | France / Biscay Gulf | To 2003 | |
| Cellana rota | Israel | 1961 | |
| Celleporaria albirostris | Australia / Bass strait | 1888 | |
| Celleporaria aperta | Israel | 1968 | |
| Celleporaria brunnea | France / Biscay Gulf | 2007 | |
| Celleporaria brunnea | France / Western Mediterranean | From 2015 | |
| Celleporaria brunnea | Greece / Eastern Mediterranean | 2015 | |
| Celleporaria brunnea | Italy / Central Mediterranean | 2010 - 2011 | |
| Celleporaria brunnea | Italy / Western Mediterranean | 2010 - 2011 | |
| Celleporaria brunnea | Portugal / Iberian Coastal | 2012 | |
| Celleporaria inaudita | Portugal / Madeira | 2014 | |
| Celleporaria vermiformis | Greece / Eastern Mediterranean | 2015 | |
| Celleporella carolinensis | Italy / Adriatic Sea | 1993 | |
| Celleporella hyalina | Australia / Bass strait | 1889 | |
| Celtodoryx ciocalyptoides | France / Biscay Gulf | 1990 - 1999 | |
| Celtodoryx ciocalyptoides | France / Celtic seas | 1996 | |
| Celtodoryx ciocalyptoides | France / North Sea | From 2014 | |
| Celtodoryx ciocalyptoides | Netherlands | To 2002 | |
| Centroceras clavulatum | Australia / Bass strait | 1971 | |
| Centroceras clavulatum | France / Biscay Gulf | 2014 | |
| Centroceras clavulatum | France / English Channel | 2017 | |
| Centropages furcatus | Greece / Eastern Mediterranean | 1988 | |
| Cephalothrix simula | Netherlands | To 2012 | |
| Cephalothrix simula | Spain / Iberian Coastal | To 2013 | |
| Ceramium botryocarpum | Netherlands | 2011 | |
| Ceramium cimbricum | Germany / North Sea | To 2010 | |
| Ceramium cimbricum | Netherlands | To 2009 | |
| Ceramium cingulatum | Portugal / Azores | 2005 - 2007 | |
| Ceramium circinatum | Germany / North Sea | 2015 | |
| Ceramium graecum | Greece / Eastern Mediterranean | 1990 | |
| Ceramium strobiliforme | Italy / Adriatic Sea | 1997 | |
| Ceramium strobiliforme | Italy / Western Mediterranean | 1991 | |
| Ceramium sungminbooi | Netherlands | To 2014 | |
| Ceramium tenuicorne | Netherlands | 2011 | |
| Ceramium virgatum | Australia / Bass strait | 1981 | |
| Cerastoderma edule | Iceland | 1948 | |
| Ceratonereis mirabilis | Israel | 1974 | |
| Cercopagis (Cercopagis) pengoi | Estonia | 1992 | |
| Cercopagis (Cercopagis) pengoi | Finland | 1992 | |
| Cercopagis (Cercopagis) pengoi | Germany / Baltic Sea | 2004 | |
| Cercopagis (Cercopagis) pengoi | Latvia | 1992 | |
| Cercopagis (Cercopagis) pengoi | Lithuania | 1999 | |
| Cercopagis (Cercopagis) pengoi | Poland | 1999 | |
| Cercopagis (Cercopagis) pengoi | Russia / Baltic Sea / Kaliningrad area | 1999 | |
| Cercopagis (Cercopagis) pengoi | Russia / Baltic Sea / St. Petersburg area | 1995 | |
| Cercopagis (Cercopagis) pengoi | Sweden / Baltic Sea | 1995 | |
| Cereus pedunculatus | Germany / North Sea | 1921 | |
| Cerithidium diplax | Israel | 1961 | |
| Cerithidium perparvulum | Greece / Eastern Mediterranean | 2010 | |
| Cerithidium perparvulum | Israel | 2004 | |
| Cerithiopsis pulvis | Greece / Eastern Mediterranean | 2010 | |
| Cerithiopsis pulvis | Israel | 1978 | |
| Cerithiopsis tenthrenois | Greece / Eastern Mediterranean | 1994 | |
| Cerithiopsis tenthrenois | Israel | 1982 | |
| Cerithium columna | Israel | 1966 | |
| Cerithium egenum | Israel | 1971 | |
| Cerithium nesioticum | Israel | 1971 | |
| Cerithium scabridum | Greece / Eastern Mediterranean | 2007 | |
| Cerithium scabridum | Israel | 1891 | |
| Cerithium scabridum | Italy / Adriatic Sea | 2005 - 2007 | |
| Cerithium scabridum | Italy / Central Mediterranean | 1976 | |
| Cerithium scabridum | Italy / Western Mediterranean | 1999 | |
| Chaetoceros aequatorialis | Bulgaria | 2011 | |
| Chaetoceros aequatorialis | Russia / Black Sea | 2004 | |
| Chaetoceros circinalis | Denmark / Baltic Sea | 2001 | |
| Chaetoceros circinalis | Denmark / North Sea | 2006 | |
| Chaetoceros concavicornis | Denmark / Baltic Sea | 2011 | |
| Chaetoceros concavicornis | Denmark / North Sea | 2011 | |
| Chaetoceros diversus var. papilionis | Georgia | 2000 | |
| Chaetoceros diversus var. papilionis | Ukraine / Black Sea | From 1999 | |
| Chaetoceros lorenzianus | Germany / Baltic Sea | 2009 | |
| Chaetoceros lorenzianus | Lithuania | 2005 | |
| Chaetoceros lorenzianus | Poland | 2003 | |
| Chaetoceros peruvianus | Denmark / Baltic Sea | 1981 | |
| Chaetoceros peruvianus | Denmark / North Sea | 1981 | |
| Chaetoceros peruvianus | France / Biscay Gulf | 1964 | |
| Chaetoceros peruvianus | France / Celtic seas | 2003 | |
| Chaetoceros peruvianus | France / English Channel | 1993 | |
| Chaetoceros peruvianus | Germany / Baltic Sea | To 2010 | |
| Chaetoceros peruvianus | Sweden / Baltic Sea | From 2007 | |
| Chaetoceros peruvianus | Sweden / North Sea | 2007 | |
| Chaetoceros rostratus | France / Celtic seas | 2003 | |
| Chaetoceros rostratus | France / English Channel | 2003 | |
| Chaetoceros throndsenii | Russia / Black Sea | 2005 | |
| Chaetoceros tortissimus | Russia / Black Sea | 2000 | |
| Chaetoceros tortissimus | Turkey / Black Sea | 1995 - 1996 | |
| Chaetoceros tortissimus | Ukraine / Black Sea | From 2001 | |
| Chaetodipterus faber | Greece / Eastern Mediterranean | 2019 | |
| Chaetodon auriga | Italy / Western Mediterranean | 2015 | |
| Chaetodon austriacus | Israel | 2011 | |
| Chaetodon larvatus | Israel | 2011 | |
| Chaetogammarus ischnus | Germany / Baltic Sea | To 2016 | |
| Chaetogammarus ischnus | Germany / North Sea | 1989 | |
| Chaetogammarus ischnus | Lithuania | 1960 | |
| Chaetogammarus ischnus | Netherlands | To 1991 | |
| Chaetogammarus ischnus | Poland | 1928 | |
| Chaetogammarus warpachowskyi | Latvia | 1966 | |
| Chaetogammarus warpachowskyi | Lithuania | 1960 | |
| Chaetogammarus warpachowskyi | Russia / Baltic Sea / Kaliningrad area | 1962 | |
| Chaetomorpha aerea | Australia / Bass strait | 1971 | |
| Chaetomorpha capillaris | Australia / Bass strait | 1983 | |
| Chaetomorpha linum | Australia / Bass strait | 1981 | |
| Chaetopleura angulata | Portugal / Iberian Coastal | To 1916 | |
| Chaetopleura angulata | Spain / Iberian Coastal | To 1850 | |
| Chaetozone corona | Greece / Central Mediterranean | 1982 | |
| Chaetozone corona | Greece / Eastern Mediterranean | 1989 | |
| Chaetozone corona | Italy / Adriatic Sea | 2006 | |
| Chaetozone corona | Italy / Central Mediterranean | 2018 | |
| Chaetozone corona | Italy / Western Mediterranean | 2014 - 2016 | |
| Chalinula loosanoffi | Germany / North Sea | To 1993 | |
| Chalinula loosanoffi | Netherlands | To 1880 | |
| Chalinula loosanoffi | United Kingdom (Britain) / English Channel | From 1970 | |
| Chalinula loosanoffi | United Kingdom (Britain) / North Sea | From 1970 | |
| Chama asperella | Greece / Eastern Mediterranean | 2007 | |
| Chama asperella | Israel | 2002 | |
| Chama gryphoides | Spain / Iberian Coastal | 2003 | |
| Chama pacifica | Greece / Eastern Mediterranean | 2005 | |
| Chama pacifica | Israel | 1988 | |
| Chama sp. | Ireland | 1989 | |
| Champsodon nudivittis | Greece / Eastern Mediterranean | 2012 | |
| Champsodon nudivittis | Israel | 2011 | |
| Chara connivens | Estonia | 1930 - 1959 | |
| Chara connivens | Finland | 2004 | |
| Chara connivens | Germany / Baltic Sea | 1858 | |
| Chara connivens | Latvia | 1920 - 1924 | |
| Chara connivens | Poland | 1900 - 1907 | |
| Chara connivens | Sweden / Baltic Sea | 1930 - 1950 | |
| Charybdis (Charybdis) feriata | Italy / Western Mediterranean | 2015 | |
| Charybdis (Charybdis) hellerii | Greece / Eastern Mediterranean | 2004 | |
| Charybdis (Charybdis) hellerii | Israel | 1925 | |
| Charybdis (Charybdis) japonica | Italy / Adriatic Sea | 2006 | |
| Charybdis (Charybdis) lucifera | Italy / Adriatic Sea | 2006 | |
| Charybdis (Goniohellenus) longicollis | Greece / Eastern Mediterranean | 1996 | |
| Charybdis (Goniohellenus) longicollis | Israel | 1961 | |
| Chattonella marina | Germany / North Sea | 1974 | |
| Chattonella marina | Netherlands | To 1991 | |
| Chattonella marina var. antiqua | Netherlands | To 1991 | |
| Cheilodipterus novemstriatus | Israel | 2010 | |
| Cheilopogon cyanopterus | France / Biscay Gulf | 2005 | |
| Chelicorophium curvispinum | Belgium | 1990 | |
| Chelicorophium curvispinum | Estonia | 2005 | |
| Chelicorophium curvispinum | France / Celtic seas | 1993 | |
| Chelicorophium curvispinum | France / English Channel | 2006 | |
| Chelicorophium curvispinum | France / North Sea | 2006 | |
| Chelicorophium curvispinum | Germany / Baltic Sea | 1932 | |
| Chelicorophium curvispinum | Germany / North Sea | 1912 | |
| Chelicorophium curvispinum | Ireland | To 2000 | |
| Chelicorophium curvispinum | Lithuania | 1921 - 1929 | |
| Chelicorophium curvispinum | Netherlands | 1987 | |
| Chelicorophium curvispinum | Poland | 1900 - 1928 | |
| Chelicorophium curvispinum | Russia / Baltic Sea / Kaliningrad area | 1921 - 1925 | |
| Chelicorophium curvispinum | Russia / Baltic Sea / St. Petersburg area | 2006 | |
| Chelicorophium robustum | Germany / Baltic Sea | To 2024 | |
| Chelicorophium robustum | Germany / North Sea | 2003 | |
| Chelicorophium robustum | Poland | 2018 | |
| Chelon haematocheilus | Turkey / Black Sea | From 1989 | |
| Chelon haematocheilus | Ukraine / Azov Sea | 1972 - 1996 | |
| Chelon haematocheilus | Ukraine / Black Sea | 1972 - 1996 | |
| Chelon labrosus | Ukraine / Black Sea | From 1983 | |
| Cherax destructor | Spain / Iberian Coastal | To 1983 | |
| Chionoecetes opilio | Norway / Barents Sea | To 2003 | |
| Chionoecetes opilio | Russia / Barents Sea | 1996 | |
| Chiton cumingsii | Spain / Canary Islands | To 2013 | |
| Chlorurus rhakoura | Italy / Central Mediterranean | 2017 | |
| Chondracanthus sp. | France / Biscay Gulf | 2009 | |
| Chondria arcuata | Australia / Bass strait | 1975 | |
| Chondria coerulescens | France / Western Mediterranean | 1993 | |
| Chondria coerulescens | Greece / Central Mediterranean | 1975 | |
| Chondria coerulescens | Greece / Eastern Mediterranean | 1982 | |
| Chondria coerulescens | Portugal / Azores | 2005 - 2007 | |
| Chondria collinsiana | Greece / Eastern Mediterranean | 1980 | |
| Chondria curvilineata | France / Western Mediterranean | 1981 | |
| Chondria curvilineata | Israel | 2013 | |
| Chondria curvilineata | Italy / Central Mediterranean | 2015 | |
| Chondria polyrhiza | Italy / Central Mediterranean | 1992 | |
| Chondria pygmaea | Italy / Adriatic Sea | 1998 | |
| Chondria pygmaea | Italy / Central Mediterranean | 1991 | |
| Chondria pygmaea | Italy / Western Mediterranean | 1995 | |
| Chondrus giganteus | France / Western Mediterranean | 1993 | |
| Chondrus giganteus f. flabellatus | France / Western Mediterranean | 1993 | |
| Chorda filum | France / Western Mediterranean | 1981 | |
| Chorizopora brongniartii | Iceland | 2015 | |
| Chorizopora brongniartii | Spain / Canary Islands | To 2003 | |
| Chromodoris quadricolor | France / Western Mediterranean | 2014 | |
| Chromodoris quadricolor | Italy / Western Mediterranean | 1982 | |
| Chrysaora hysoscella | Turkey / Black Sea | 2009 | |
| Chrysaora pseudoocellata | Israel | 2019 | |
| Chrysonephos lewisii | Italy / Western Mediterranean | 1992 | |
| Chrysymenia ventricosa | Turkey / Black Sea | 1990 - 1999 | |
| Chrysymenia wrightii | France / English Channel | 2013 | |
| Cinachyrella alloclada | Portugal / Azores | To 1989 | |
| Cingulina isseli | Israel | 1980 | |
| Ciona intestinalis | Australia / Bass strait | 1958 | |
| Ciona intestinalis | Canada / Bay of Fundy | 1850 - 1859 | |
| Ciona intestinalis | Canada / South-eastern Scotian Shelf | 1997 | |
| Ciona intestinalis | Canada / Southern Gulf of St. Lawrence and Eastern Scotian Shelf | 2004 | |
| Ciona intestinalis | Canada / Southern Newfoundland and Southern Grand Banks | 2012 | |
| Ciona intestinalis | France / English Channel | To 2012 | |
| Ciona intestinalis | Iceland | 2007 | |
| Ciona intestinalis | Portugal / Madeira | 1992 - 1993 | |
| Ciona robusta | France / Biscay Gulf | 1970 - 1979 | |
| Ciona robusta | Greece / Eastern Mediterranean | 1901 | |
| Ciona robusta | Iceland | 2019 | |
| Ciona robusta | Italy / Adriatic Sea | 2013 | |
| Circenita callipyga | Israel | 1972 | |
| Circulus octoliratus | Israel | 2018 | |
| Cirolana harfordi | Australia / Bass strait | 1996 | |
| Cirrenalia basiminuta | Ukraine / Black Sea | 2001 | |
| Cirrholovenia tetranema | Italy / Western Mediterranean | 1963 | |
| Cladophora flexuosa | Turkey / Black Sea | 1990 - 1999 | |
| Cladophora hutchinsiae | Bulgaria | 1938 | |
| Cladophora patentiramea | Israel | 2014 | |
| Cladophora prolifera | Australia / Bass strait | 1964 | |
| Cladophoropsis membranacea | Portugal / Azores | 1986 | |
| Cladosiphon zosterae | France / Western Mediterranean | 1993 | |
| Cladostephus spongiosus | Australia / Bass strait | 1966 | |
| Clausocalanus arcuicornis | Romania | 1978 | |
| Clausocalanus arcuicornis | Ukraine / Black Sea | From 2001 | |
| Clavelina dellavallei | Portugal / Madeira | To 1995 | |
| Clavelina lepadiformis | Portugal / Azores | To 1971 | |
| Clavelina lepadiformis | Portugal / Madeira | To 1995 | |
| Clavelina oblonga | France / Western Mediterranean | From 1986 | |
| Clavelina oblonga | Italy / Central Mediterranean | To 2008 | |
| Clavelina oblonga | Italy / Western Mediterranean | To 1929 | |
| Clavelina oblonga | Portugal / Azores | To 1971 | |
| Clavelina oblonga | Portugal / Madeira | 2013 | |
| Claviceps purpurea | Belgium | To 2008 | |
| Claviceps purpurea | Germany / North Sea | 2001 | |
| Claviceps purpurea | Netherlands | 1990 - 1999 | |
| Clementia papyracea | Greece / Eastern Mediterranean | 1985 | |
| Clementia papyracea | Israel | 1937 | |
| Clorida albolitura | Israel | 2006 | |
| Clymenella torquata | France / English Channel | 1977 | |
| Clymenella torquata | Germany / North Sea | 2021 | |
| Clymenella torquata | Ireland | 1974 - 1981 | |
| Clymenella torquata | United Kingdom (Britain) / North Sea | 1936 | |
| Clypeomorus bifasciatus | Israel | 1983 | |
| Clytia brevithecata | Italy / Adriatic Sea | 2001 | |
| Clytia brevithecata | Italy / Central Mediterranean | 1996 | |
| Clytia brevithecata | Italy / Western Mediterranean | 2003 | |
| Clytia hemisphaerica | Australia / Bass strait | 1980 | |
| Clytia linearis | France / Western Mediterranean | 1949 | |
| Clytia linearis | Greece / Central Mediterranean | 1977 | |
| Clytia linearis | Greece / Eastern Mediterranean | 1981 | |
| Clytia linearis | Italy / Adriatic Sea | To 1996 | |
| Clytia linearis | Italy / Central Mediterranean | 1991 | |
| Clytia linearis | Italy / Western Mediterranean | 1956 - 1959 | |
| Clytia mccradyi | Italy / Western Mediterranean | 1961 - 1963 | |
| Clytia paulensis | Australia / Bass strait | 1985 | |
| Cocconeis britannica | Ukraine / Black Sea | From 1902 | |
| Codium adhaerens | Spain / Iberian Coastal | To 2006 | |
| Codium arabicum | Israel | 2007 | |
| Codium arabicum | Portugal / Iberian Coastal | 2006 | |
| Codium fragile | Canada / Northern Newfoundland | 2013 | |
| Codium fragile | Canada / South-eastern Scotian Shelf | 1989 | |
| Codium fragile | Canada / Southern Gulf of St. Lawrence and Eastern Scotian Shelf | 1996 | |
| Codium fragile | Canada / Southern Newfoundland and Southern Grand Banks | 2012 | |
| Codium fragile | Norway / North Sea | 1946 | |
| Codium fragile | Spain / Canary Islands | To 2003 | |
| Codium fragile | Sweden / North Sea | 1932 | |
| Codium fragile atlanticum | Netherlands | To 1923 | |
| Codium fragile atlanticum | Norway / North Sea | 1895 | |
| Codium fragile atlanticum | Norway / Norwegian Sea | 1895 | |
| Codium fragile atlanticum | Portugal / Azores | To 1994 | |
| Codium fragile scandinavicum | Norway / North Sea | 1929 | |
| Codium fragile scandinavicum | Norway / Norwegian Sea | 1929 | |
| Codium fragile subsp. fragile | Australia / Bass strait | 1997 | |
| Codium fragile subsp. fragile | Belgium | 1939 | |
| Codium fragile subsp. fragile | Denmark / Baltic Sea | 1920 | |
| Codium fragile subsp. fragile | Denmark / North Sea | 1920 | |
| Codium fragile subsp. fragile | France / Biscay Gulf | 1946 | |
| Codium fragile subsp. fragile | France / Celtic seas | 1946 | |
| Codium fragile subsp. fragile | France / English Channel | 1940 | |
| Codium fragile subsp. fragile | France / North Sea | 1940 | |
| Codium fragile subsp. fragile | France / Western Mediterranean | 1946 | |
| Codium fragile subsp. fragile | Germany / North Sea | 1930 | |
| Codium fragile subsp. fragile | Greece / Central Mediterranean | 1985 | |
| Codium fragile subsp. fragile | Greece / Eastern Mediterranean | 1992 | |
| Codium fragile subsp. fragile | Iceland | 1974 | |
| Codium fragile subsp. fragile | Ireland | 1941 | |
| Codium fragile subsp. fragile | Italy / Adriatic Sea | 1978 | |
| Codium fragile subsp. fragile | Italy / Central Mediterranean | 1973 | |
| Codium fragile subsp. fragile | Italy / Western Mediterranean | 1978 - 1987 | |
| Codium fragile subsp. fragile | Netherlands | 1900 | |
| Codium fragile subsp. fragile | Norway / Barents Sea | 1946 | |
| Codium fragile subsp. fragile | Norway / North Sea | 1946 | |
| Codium fragile subsp. fragile | Norway / Norwegian Sea | 1946 | |
| Codium fragile subsp. fragile | Portugal / Azores | 1993 | |
| Codium fragile subsp. fragile | Portugal / Iberian Coastal | 2005 | |
| Codium fragile subsp. fragile | Spain / Canary Islands | To 2004 | |
| Codium fragile subsp. fragile | Spain / Iberian Coastal | To 1957 | |
| Codium fragile subsp. fragile | Turkey / Black Sea | From 1983 | |
| Codium fragile subsp. fragile | United Kingdom (Britain) / Celtic seas | 1891 | |
| Codium fragile subsp. fragile | United Kingdom (Britain) / English Channel | 1891 | |
| Codium fragile subsp. fragile | United Kingdom (Britain) / North Sea / Orkney Islands | From 1960 | |
| Codium parvulum | Israel | 2004 | |
| Codium pulvinatum | Israel | 2014 | |
| Codium taylorii | Israel | 1939 | |
| Codium vermilara | Portugal / Azores | To 1995 | |
| Colaconema codicola | France / Western Mediterranean | 1950 | |
| Colaconema codicola | Italy / Adriatic Sea | 1978 | |
| Colaconema codicola | Italy / Western Mediterranean | To 1984 | |
| Colaconema codicola | Turkey / Black Sea | 1994 | |
| Colaconema dasyae | Netherlands | 1951 | |
| Colaconema garbaryi | Australia / Bass strait | 1977 | |
| Colaconema savianum | Netherlands | 1960 - 1969 | |
| Coleusia signata | Greece / Eastern Mediterranean | 2005 | |
| Coleusia signata | Israel | 1953 | |
| Colpomenia peregrina | Australia / Bass strait | 1971 | |
| Colpomenia peregrina | Denmark / Baltic Sea | 1939 | |
| Colpomenia peregrina | Denmark / North Sea | 1939 | |
| Colpomenia peregrina | France / Biscay Gulf | 1905 | |
| Colpomenia peregrina | France / Celtic seas | 1905 | |
| Colpomenia peregrina | France / English Channel | 1905 | |
| Colpomenia peregrina | France / North Sea | 1971 | |
| Colpomenia peregrina | France / Western Mediterranean | 1918 - 1957 | |
| Colpomenia peregrina | Germany / North Sea | 2017 | |
| Colpomenia peregrina | Greece / Central Mediterranean | 2001 | |
| Colpomenia peregrina | Greece / Eastern Mediterranean | 1986 | |
| Colpomenia peregrina | Ireland | To 1935 | |
| Colpomenia peregrina | Italy / Central Mediterranean | To 1975 | |
| Colpomenia peregrina | Italy / Western Mediterranean | 1964 | |
| Colpomenia peregrina | Netherlands | 1921 | |
| Colpomenia peregrina | Norway / North Sea | 1933 | |
| Colpomenia peregrina | Norway / Norwegian Sea | 1933 | |
| Colpomenia peregrina | Portugal / Azores | To 1994 | |
| Colpomenia peregrina | Portugal / Iberian Coastal | 1951 | |
| Colpomenia peregrina | Spain / Canary Islands | To 1978 | |
| Colpomenia peregrina | Spain / Iberian Coastal | To 1960 | |
| Colpomenia peregrina | Sweden / North Sea | 1950 | |
| Colpomenia peregrina | United Kingdom (Britain) / Celtic seas | 1907 | |
| Colpomenia peregrina | United Kingdom (Britain) / English Channel | 1907 | |
| Colpomenia peregrina | United Kingdom (Britain) / North Sea | 1908 - 1930 | |
| Colpomenia peregrina | United Kingdom (Britain) / North Sea / Orkney Islands | To 1960 | |
| Colpomenia sinuosa | Australia / Bass strait | 1966 | |
| Colpomenia sinuosa | Portugal / Madeira | 1870 | |
| Conchoderma auritum | Belgium | To 2010 | |
| Conchoderma auritum | Netherlands | 1976 | |
| Congeria leucophaeta leucophaeta | Germany / Baltic Sea | To 2013 | |
| Congeria leucophaeta leucophaeta | Germany / North Sea | 1930 | |
| Conomurex persicus | Greece / Central Mediterranean | 2001 | |
| Conomurex persicus | Greece / Eastern Mediterranean | 1983 | |
| Conomurex persicus | Israel | 1983 | |
| Conopeum reticulum | Australia / Bass strait | 1879 | |
| Conopeum seurati | Russia / Caspian Sea | 1958 | |
| Conopeum seurati | United Kingdom (Britain) / North Sea / Orkney Islands | 1994 | |
| Conradia eutornisca | Israel | 1989 | |
| Conus arenatus arenatus | Israel | 1937 | |
| Conus fumigatus | Israel | 2016 | |
| Coolia monotis | Greece / Eastern Mediterranean | 2002 | |
| Corambe obscura | Bulgaria | 1986 | |
| Corambe obscura | France / Biscay Gulf | 1973 | |
| Corambe obscura | France / Celtic seas | 1973 | |
| Corambe obscura | Germany / North Sea | 2019 | |
| Corambe obscura | Netherlands | 1879 | |
| Corambe obscura | Romania | 1990 | |
| Corambe obscura | Russia / Azov Sea | 1986 | |
| Corambe obscura | Ukraine / Azov Sea | From 1989 | |
| Corambe obscura | Ukraine / Black Sea | From 1989 | |
| Corbicula fluminalis | Belgium | To 1992 | |
| Corbicula fluminalis | Germany / North Sea | To 1983 | |
| Corbicula fluminalis | Netherlands | To 1990 | |
| Corbicula fluminalis | Portugal / Iberian Coastal | 1980 - 1989 | |
| Corbicula fluminalis | Ukraine / Black Sea | 2000 - 2003 | |
| Corbicula fluminea | Belgium | To 1992 | |
| Corbicula fluminea | Germany / North Sea | 1983 | |
| Corbicula fluminea | Ireland | To 2010 | |
| Corbicula fluminea | Netherlands | To 1998 | |
| Corbicula fluminea | Portugal / Iberian Coastal | To 1978 | |
| Corbicula fluminea | Spain / Iberian Coastal | 1994 | |
| Corbicula fluminea | Ukraine / Black Sea | 1995 - 2000 | |
| Corbicula fluminea | United Kingdom (Britain) / North Sea | 1998 | |
| Cordylophora caspia | Belgium | 1905 | |
| Cordylophora caspia | Denmark / Baltic Sea | 1891 - 1899 | |
| Cordylophora caspia | Denmark / North Sea | 1895 | |
| Cordylophora caspia | Estonia | 1801 - 1850 | |
| Cordylophora caspia | Finland | 1801 - 1889 | |
| Cordylophora caspia | France / Biscay Gulf | 1901 | |
| Cordylophora caspia | France / Celtic seas | 1901 | |
| Cordylophora caspia | France / English Channel | To 1901 | |
| Cordylophora caspia | Germany / Baltic Sea | 1858 | |
| Cordylophora caspia | Germany / North Sea | 1858 | |
| Cordylophora caspia | Ireland | To 1844 | |
| Cordylophora caspia | Italy / Adriatic Sea | 1978 | |
| Cordylophora caspia | Italy / Central Mediterranean | 1978 | |
| Cordylophora caspia | Italy / Western Mediterranean | 1978 | |
| Cordylophora caspia | Latvia | 1801 - 1899 | |
| Cordylophora caspia | Lithuania | 1801 - 1899 | |
| Cordylophora caspia | Netherlands | 1884 | |
| Cordylophora caspia | Norway / North Sea | 1985 | |
| Cordylophora caspia | Poland | 1801 - 1850 | |
| Cordylophora caspia | Portugal / Iberian Coastal | To 1983 | |
| Cordylophora caspia | Russia / Baltic Sea / Kaliningrad area | 1860 - 1870 | |
| Cordylophora caspia | Russia / Baltic Sea / St. Petersburg area | 1979 | |
| Cordylophora caspia | Sweden / Baltic Sea | 1810 | |
| Cordylophora caspia | Sweden / North Sea | 1895 - 1971 | |
| Cordylophora caspia | Ukraine / Black Sea | 1950 - 1959 | |
| Cordylophora caspia | United Kingdom (Britain) / Celtic seas | | |
| Cordylophora caspia | United Kingdom (Britain) / English Channel | | |
| Cordylophora caspia | United Kingdom (Britain) / North Sea | | |
| Coregonus autumnalis | Latvia | 1957 | |
| Coregonus autumnalis | Russia / Baltic Sea / St. Petersburg area | 1953 - 1957 | |
| Coregonus muksun | Latvia | 1970 | |
| Coregonus muksun | Poland | 1984 | |
| Coregonus nasus | Latvia | 1960 | |
| Coregonus peled | Estonia | 1959 | |
| Coregonus peled | Finland | 1965 | |
| Coregonus peled | Latvia | 1954 | |
| Coregonus peled | Lithuania | 1960 | |
| Coregonus peled | Poland | 1966 | |
| Coregonus peled | Russia / Baltic Sea / Kaliningrad area | 1958 | |
| Coregonus peled | Russia / Baltic Sea / St. Petersburg area | 1955 - 1956 | |
| Corella eumyota | France / Biscay Gulf | To 2002 | |
| Corella eumyota | France / Celtic seas | To 2006 | |
| Corella eumyota | France / English Channel | 2002 | |
| Corella eumyota | France / North Sea | 2007 | |
| Corella eumyota | Germany / North Sea | 2016 | |
| Corella eumyota | Ireland | 2005 | |
| Corella eumyota | Netherlands | 2007 | |
| Corella eumyota | Portugal / Iberian Coastal | 2008 | |
| Corella eumyota | Spain / Iberian Coastal | To 2008 | |
| Corella eumyota | United Kingdom (Britain) / Celtic seas | 2004 | |
| Corella eumyota | United Kingdom (Britain) / English Channel | 2004 | |
| Corella eumyota | United Kingdom (Britain) / North Sea | 2009 - 2013 | |
| Corella eumyota | United Kingdom (Britain) / North Sea / Orkney Islands | To 2012 | |
| Corethron pennatum | Netherlands | To 2018 | |
| Coriophora lessepsiana | Israel | 2018 | |
| Cornigerius maeoticus | Russia / Baltic Sea / St. Petersburg area | 2003 | |
| Corollospora lacera | Ukraine / Black Sea | 1992 | |
| Corophium volutator | Russia / Caspian Sea | 1950 - 1959 | |
| Corymbellus aureus | Denmark / Baltic Sea | 1992 | |
| Corymbellus aureus | Denmark / North Sea | 1989 | |
| Coryne eximia | Australia / Bass strait | 1884 | |
| Corynomorpha prismatica | Portugal / Azores | 1990 | |
| Corynophlaea verruculiformis | Netherlands | 1994 | |
| Coryphellina rubrolineata | Greece / Eastern Mediterranean | 2009 | |
| Coryphellina rubrolineata | Israel | 1988 | |
| Coscinasterias tenuispina | Spain / Iberian Coastal | 2000 | |
| Coscinodiscus wailesii | Belgium | 1977 - 1978 | |
| Coscinodiscus wailesii | Denmark / Baltic Sea | 1983 - 1989 | |
| Coscinodiscus wailesii | Denmark / North Sea | 1983 | |
| Coscinodiscus wailesii | France / Biscay Gulf | 1972 - 1978 | |
| Coscinodiscus wailesii | France / Celtic seas | 1978 | |
| Coscinodiscus wailesii | France / English Channel | 1978 | |
| Coscinodiscus wailesii | Germany / North Sea | 1977 | |
| Coscinodiscus wailesii | Ireland | 1979 | |
| Coscinodiscus wailesii | Netherlands | 1978 | |
| Coscinodiscus wailesii | Norway / North Sea | 1979 | |
| Coscinodiscus wailesii | Sweden / Baltic Sea | 1995 - 2005 | |
| Coscinodiscus wailesii | Sweden / North Sea | To 1995 | |
| Coscinodiscus wailesii | United Kingdom (Britain) / Celtic seas | 1977 | |
| Coscinodiscus wailesii | United Kingdom (Britain) / English Channel | 1977 | |
| Cossura coasta | Greece / Central Mediterranean | 1980 | |
| Cossura coasta | Greece / Eastern Mediterranean | 1975 | |
| Costellipitar chordatus | Israel | 2012 | |
| Cotula coronopifolia | Germany / North Sea | 1739 | |
| Cotula coronopifolia | Netherlands | 1846 | |
| Cotylorhiza erythraea | Israel | 2003 | |
| Cradoscrupocellaria bertholletii | Australia / Bass strait | From 1900 | |
| Cradoscrupocellaria bertholletii | Portugal / Madeira | 2006 | |
| Crambe crambe | Portugal / Madeira | To 2004 | |
| Crangon crangon | Iceland | 2003 | |
| Crangonyx pseudogracilis | Ireland | 1975 - 1993 | |
| Craspedacusta sowerbii | Germany / North Sea | 1960 - 1969 | |
| Craspedacusta sowerbii | Ireland | To 2013 | |
| Crassicorophium bonellii | United Kingdom (Britain) / North Sea / Orkney Islands | 1995 | |
| Crassicorophium crassicorne | United Kingdom (Britain) / North Sea / Orkney Islands | 1995 | |
| Crassimarginatella papulifera | Spain / Iberian Coastal | To 2016 | |
| Crassostrea rhizophorae | France / Celtic seas | 1976 | |
| Crassostrea rhizophorae | United Kingdom (Britain) / Celtic seas | 1981 | |
| Crassostrea rivularis | France / Celtic seas | 1994 | |
| Crassostrea sikamea | France / Celtic seas | 1994 | |
| Crassostrea virginica | Belgium | 1960 - 1969 | |
| Crassostrea virginica | Denmark / Baltic Sea | 1880 | |
| Crassostrea virginica | France / Biscay Gulf | 1861 | |
| Crassostrea virginica | France / Celtic seas | 1861 | |
| Crassostrea virginica | Germany / Baltic Sea | 1886 - 1896 | |
| Crassostrea virginica | Germany / North Sea | 1911 | |
| Crassostrea virginica | Ireland | 1870 | |
| Crassostrea virginica | Netherlands | To 1943 | |
| Crassostrea virginica | Romania | 1973 | |
| Crassostrea virginica | Sweden / North Sea | | |
| Crassostrea virginica | United Kingdom (Britain) / North Sea | 1872 | |
| Crenidens crenidens | Israel | 1992 | |
| Crepidacantha poissonii | Greece / Eastern Mediterranean | 1986 | |
| Crepidacantha poissonii | Italy / Central Mediterranean | 1982 | |
| Crepidula fornicata | Belgium | 1911 | |
| Crepidula fornicata | Denmark / Baltic Sea | 1934 | |
| Crepidula fornicata | Denmark / North Sea | 1934 | |
| Crepidula fornicata | France / Biscay Gulf | 1934 | |
| Crepidula fornicata | France / Celtic seas | 1949 | |
| Crepidula fornicata | France / English Channel | 1934 | |
| Crepidula fornicata | France / North Sea | 1962 | |
| Crepidula fornicata | France / Western Mediterranean | 1957 | |
| Crepidula fornicata | Germany / North Sea | 1934 | |
| Crepidula fornicata | Greece / Eastern Mediterranean | 1985 | |
| Crepidula fornicata | Ireland | 1893 | |
| Crepidula fornicata | Italy / Central Mediterranean | 1973 | |
| Crepidula fornicata | Italy / Western Mediterranean | 1983 | |
| Crepidula fornicata | Netherlands | 1929 | |
| Crepidula fornicata | Norway / Barents Sea | To 1985 | |
| Crepidula fornicata | Norway / North Sea | 1958 - 1985 | |
| Crepidula fornicata | Norway / Norwegian Sea | To 1985 | |
| Crepidula fornicata | Portugal / Iberian Coastal | To 1999 | |
| Crepidula fornicata | Spain / Iberian Coastal | To 1983 | |
| Crepidula fornicata | Sweden / North Sea | 1950 | |
| Crepidula fornicata | United Kingdom (Britain) / Celtic seas | 1872 | |
| Crepidula fornicata | United Kingdom (Britain) / English Channel | 1872 | |
| Crepidula fornicata | United Kingdom (Britain) / North Sea | 1887 - 1890 | |
| Crepipatella dilatata | Portugal / Iberian Coastal | 2023 | |
| Crepipatella dilatata | Spain / Iberian Coastal | 2005 | |
| Cristapseudes omercooperi | Israel | 2005 | |
| Crisularia serrata | France / Western Mediterranean | 1902 | |
| Crisularia serrata | Greece / Eastern Mediterranean | 1967 | |
| Crisularia serrata | Italy / Western Mediterranean | 1986 - 1987 | |
| Critomolgus actiniae | Ireland | 1973 | |
| Cryptocentrus caeruleopunctatus | Israel | 2014 | |
| Cryptonemia hibernica | France / English Channel | 1980 | |
| Cryptonemia hibernica | Ireland | 1971 | |
| Cryptonemia hibernica | United Kingdom (Britain) / English Channel | 2000 | |
| Cryptonemia lomation | United Kingdom (Britain) / Celtic seas | 1983 | |
| Cryptorchestia cavimana | Belgium | To 2002 | |
| Cryptorchestia cavimana | Germany / Baltic Sea | To 1925 | |
| Cryptorchestia cavimana | Germany / North Sea | To 1920 | |
| Cryptorchestia cavimana | Netherlands | 1878 | |
| Cryptorchestia cavimana | Poland | To 1925 | |
| Cryptosula pallasiana | Australia / Bass strait | 1886 - 1889 | |
| Cryptosula pallasiana | New Zealand / New Zealand Shelf / North Island | To 1890 | |
| Cryptosula pallasiana | New Zealand / New Zealand Shelf / South Island | To 1890 | |
| Cryptosula pallasiana | Portugal / Madeira | 2014 | |
| Ctenodrilus serratus | Portugal / Madeira | 1992 | |
| Ctenodrilus serratus | United Kingdom (Britain) / North Sea / Orkney Islands | 2015 | |
| Ctenogobius boleosoma | Italy / Central Mediterranean | 2021 | |
| Ctenopharyngodon idella | Denmark / Baltic Sea | 2008 | |
| Ctenopharyngodon idella | Finland | 1970 - 1979 | |
| Cucurbitula cymbium | Israel | 1954 | |
| Cumulospora marina | Ukraine / Black Sea | From 2001 | |
| Cumulospora varia | Ukraine / Black Sea | 2001 | |
| Cuthona perca | Italy / Adriatic Sea | 1976 - 1977 | |
| Cuthona perca | Ukraine / Black Sea | 2007 | |
| Cutleria multifida | Australia / Bass strait | 1966 | |
| Cutleria multifida | Greece / Central Mediterranean | 1975 | |
| Cutleria multifida | Greece / Eastern Mediterranean | 1932 | |
| Cutleria multifida | Italy / Adriatic Sea | To 2000 | |
| Cutleria multifida | Italy / Western Mediterranean | 2012 | |
| Cyclichthys spilostylus | Israel | 1992 | |
| Cycloscala hyalina | Israel | 2018 | |
| Cylichna villersii | Israel | 2008 | |
| Cymbaloporetta plana | Greece / Eastern Mediterranean | 2001 - 2006 | |
| Cymodoce fuscina | Greece / Eastern Mediterranean | 2015 | |
| Cymodocea nodosa | Turkey / Black Sea | 2000 - 2009 | |
| Cynoglossus sinusarabici | Israel | 1953 | |
| Cynoscion nebulosus | Spain / Iberian Coastal | To 2013 | |
| Cynoscion regalis | France / Biscay Gulf | 2021 | |
| Cynoscion regalis | Portugal / Iberian Coastal | To 2016 | |
| Cyprinus carpio | Denmark / Baltic Sea | 1879 | |
| Cyprinus carpio | Denmark / North Sea | 1879 | |
| Cyprinus carpio | Estonia | 1893 | |
| Cyprinus carpio | Finland | 1958 | |
| Cyprinus carpio | Latvia | 1201 - 1300 | |
| Cyprinus carpio | Lithuania | 1501 - 1600 | |
| Cyprinus carpio | Poland | 1200 - 1300 | |
| Cyprinus carpio | Russia / Baltic Sea / Kaliningrad area | 1501 - 1599 | |
| Cyprinus carpio | Russia / Baltic Sea / St. Petersburg area | 1893 - 1899 | |
| Cyprinus carpio | Sweden / Baltic Sea | 1952 | |
| Cystodytes dellechiajei | Portugal / Azores | To 1969 | |
| Cystodytes dellechiajei | Portugal / Madeira | To 1995 | |
