| Species |
Recipient region |
Date of the first record |
|
| Jaera (Jaera) istri | Belgium | To 2000 |  |
| Jaera (Jaera) istri | Germany / North Sea | 1995 | |
| Jania longifurca | Portugal / Azores | 1986 | |
| Jania longifurca | Turkey / Black Sea | 2000 - 2009 | |
| Janolus hyalinus | Australia / Bass strait | 1986 | |
| Jassa marmorata | Australia / Bass strait | 1997 | |
| Jassa marmorata | Belgium | To 2011 | |
| Jassa marmorata | Denmark / North Sea | 2003 | |
| Jassa marmorata | France / Biscay Gulf | To 1992 | |
| Jassa marmorata | Germany / Baltic Sea | 2010 | |
| Jassa marmorata | Germany / North Sea | 1999 | |
| Jassa marmorata | Ireland | To 1983 | |
| Jassa marmorata | Italy / Adriatic Sea | 1977 - 1981 | |
| Jassa marmorata | Italy / Central Mediterranean | From 1976 | |
| Jassa marmorata | Italy / Western Mediterranean | 1974 | |
| Jassa marmorata | Netherlands | To 2009 | |
| Jassa marmorata | Portugal / Madeira | 1991 | |
| Jassa marmorata | United Kingdom (Britain) / North Sea / Orkney Islands | From 2013 | |
| Jassa slatteryi | Italy / Adriatic Sea | 2000 | |
| Jassa slatteryi | Italy / Central Mediterranean | 1952 | |
| Jassa slatteryi | Italy / Western Mediterranean | 2007 | |
| Jasus lalandii | Portugal / Iberian Coastal | To 1982 | |
| Jaydia queketti | Israel | 2007 | |
| Jaydia smithi | Israel | 2007 | |
| Jellyella tuberculata | Spain / Canary Islands | To 2003 | |
| Joculator problematicus | Israel | 2018 | |
