| Algae | Antithamnionella spirographidis* | None | Definite | Estab | |
| Algae | Codium fragile ssp. Fragile | 1957 | Definite | Estab | |
| Cnidarians-Hydrozoans | Cordylophora caspia | 1922 | Definite | Estab | |
| Cnidarians-Hydrozoans | Ectopleura crocea | 2003 | Definite | Estab | |
| Platyhelminthes | Gyrodactylus anguillae* | 1998 | Definite | Estab | |
| Mollusks-Bivalves | Magallana gigas | 1984 | Definite | Estab | |
| Crustaceans-Amphipods | Monocorophium acherusicum | 1999 | Definite | Estab | |
| Mollusks-Gastropods | Okenia plana | 1983 | Definite | Estab | |
| Annelids-Polychaetes | Polydora hoplura | 1992 | Definite | Estab | |
| Crustaceans-Isopods | Sphaeroma walkeri | None | Definite | Estab | |
| Mollusks-Bivalves | Teredo navalis | 1961 | Definite | Estab | |
| Bryozoans | Watersipora arcuata | 2001 | Definite | Estab | |