Common name | Scientific name | Origin | Habitat | Source |
| Terrestrial plants | | | | |
| European dune grass | Ammophila arenaria | Europe | Coastal foredune | Dawson and Foster, 1982 |
| Sea rocket | Cakile edentula | E. North America | Coastal foredune | Hickman, 1993 |
| Sea rocket | Cakile maritima | Europe | Coastal foredune | Hickman, 1993 |
| Sea fig | Carpobrotus chilensis | S. Africa | Coastal foredune | Hickman, 1993 |
| Hottentot fig | Carpobrotus edulis | S. Africa | Coastal foredune | Hickman, 1993; Dawson and Foster, 1982 |
| Brass buttons | Cotula coronopifolia | S. Africa | Elkhorn Slough | Hickman, 1993 |
| Cut-leaved plantain | Plantago coronopus | Europe | Elkhorn Slough | Hickman, 1993 |
| Sand spurrey | Spergularia bocconii | Europe | Elkhorn Slough | Hickman, 1993 |
| Narrow-leaf cattail | Typha angustifolia | | Elkhorn Slough | DeVogelaere et al., in progress |
| Algae | | | | |
| brown alga | Sargassum muticum | probably Japan | Elkhorn Slough | Dawson and Foster, 1982 |
| Invertebrates | | | | |
| sponge | Halichondria bowerbankii | east U.S. | Elkhorn Slough | Pearse, pers. comm. |
| sponge | Hymeniacidon sp. | | Elkhorn Slough | Pearse, pers. comm. |
| hydroid | Ectopleura (Tubularia) crocea | Atlantic | Elkhorn Slough | Smith and Carlton, 1980; Carlton, pers. comm. |
| Moon jelly | Aurelia sp. | Japan | Pelagic zone | Greenberg et al., 1996 |
| anemone | Diadumene lineata (Haliplanella luciae) | Japan | Elkhorn Slough | Smith and Carlton, 1980; Carlton, pers. comm. |
| nudibranch | Tenellia adspersa | Atlantic | Elkhorn Slough | Smith and Carlton, 1980 |
| Mud snail | Batillaria attramentaria | Japan | Elkhorn Slough | Smith and Carlton, 1980 |
| snail | Myosotella myosotis (Ovatella myosotis) | Atlantic | Elkhorn Slough | Smith and Carlton, 1980; Carlton, pers. comm. |
| mussel | Mytilus galloprovincialis | S. Europe | Elkhorn Slough, rocky coast | McDonald and Koehn, 1988 |
| Gem clam | Gemma gemma | Atlantic | Elkhorn Slough | Smith and Carlton, 1980 |
| Japanese cockle | Vererupis philippinarum (Tapes japonica) | Japan | Elkhorn Slough | Smith and Carlton, 1980; Carlton, pers. comm. |
| Soft-shelled clam | Mya arenaria | Atlantic | Elkhorn Slough | Smith and Carlton, 1980 |
| Shipworm | Lyrodus pedicellatus | | Elkhorn Slough | Smith and Carlton, 1980 |
| polychaete | Polydora ligni | Atlantic | Elkhorn Slough | Smith and Carlton, 1980 |
| polychaete | Pseudopolydora paucibranchiata | Japan | Elkhorn Slough | Smith and Carlton, 1980 |
| polychaete | Streblospio benedicti | Atlantic | Elkhorn Slough | Smith and Carlton, 1980 |
| polychaete | Mercierella enigmatica | Australasia | Old Salinas River | Alicea, pers. comm.; Smith and Carlton, 1980 |
| copepod | Mytilicola orientalis | Japan | Elkhorn Slough | Smith and Carlton, 1980 |
| isopod | Limnoria quadripunctata | | Elkhorn Slough | Smith and Carlton, 1980 |
| amphipod | Corophium acherusicum | | Elkhorn Slough | Smith and Carlton, 1980 |
| amphipod | Corophium insidiosum | Atlantic | Elkhorn Slough | Smith and Carlton, 1980 |
| amphipod | Corophium uenoi | Japan | Elkhorn Slough | Smith and Carlton, 1980 |
| amphipod | Melita nitida | east U. S. | Elkhorn Slough | Slattery, pers. comm. |
| amphipod | Grandidierella japonica | Asia | Elkhorn Slough | Smith and Carlton, 1980 |
| amphipod | Ampithoe valida | east U. S. | Elkhorn Slough | Slattery, pers. comm. |
| amphipod | Parapleustes derzhavini | | Elkhorn Slough | Slattery, pers. comm. |
| amphipod | Jassa marmorata | Atlantic | Harbors (fouling) | Conlan, 1990; Carlton, pers. comm. |
| Green crab | Carcinus maenas | Europe | Elkhorn Slough | Grosholz and Ruiz, 1996 |
| Oriental shrimp | Palaemon macrodactylus | Korea/Japan/China | Moss Landing Harbor | Standing, 1981 |
| Skeleton shrimp | Caprella mutica | Japan | Elkhorn Slough | Marelli, 1982 |
| bryozoan | Schizoporella unicornis | Asia | Elkhorn Slough | Smith and Carlton, 1980 |
| bryozoan | Watersipora sp. | | Elkhorn Slough | Pearse, pers. comm. |
| Vertebrates | | | | |
| Yellowfin goby | Acanthogobius flavimanus | Japan, China, Korea | Elkhorn Slough | Eschmeyer et al., 1983 |
| American shad (anadromous) | Alosa sapioissima | Atlantic | Pelagic zone | Eschmeyer et al., 1983 |
| Striped bass (anadromous) | Morone saxatilis | Atlantic | Pelagic zone | Eschmeyer et al., 1983 |
| Red fox | Vulpes vulpes subspecies | North America | Coastal foredune | Jurek, 1992 |
| Norway rat | Rattus norvegicus | Europe | Harbors | Slattery. pers. comm. |
| The following species have not been observed in Elkhorn Slough or Moss Landing Harbor, but are potential invaders if not yet present (Slattery, pers. comm.; Carlton, pers. comm.) | | | | |
| Invertebrates | | | | |
| snail | Philine auriformis | New Zealand | Elkhorn Slough | Slattery, pers. comm. |
| clam | Musculista senhousei | Japan | Elkhorn Slough | Slattery, pers. comm. |
| clam | Potamocorbula amurensis | Asia | Elkhorn Slough | Slattery, pers. comm. |
| amphipod | Ampelisca abdita | east U.S. | Elkhorn Slough | Slattery, pers. comm. |
| Chinese mitten crab | Eriocheir sinensis | China/Korea | Elkhorn Slough | Slattery, pers. comm. |
| tunicate | Botrylloides sp. | | Moss Landing Harbor | Carlton, pers. comm. |
| tunicate | Styela clava | | Moss Landing Harbor | Carlton, pers. comm. |
| tunicate | Ciona sp. | | Moss Landing Harbor | Carlton, pers. comm. |
| bryozoan | Bowerbankia gracilis | | Moss Landing Harbor | Carlton, pers. comm. |
| bryozoan | Bugula "neritina" | | Moss Landing Harbor | Carlton, pers. comm. |