Invasion
Invasion Description
1st Record: CA/Walker Creek, Tomales Bay (1993, introduced, established, Grosholz and Ruiz 1995)
Geographic Extent
CA/Walker Creek, Tomales Bay (1993, introduced, established, Grosholz and Ruiz 1995)
Vectors
| Level | Vector |
|---|---|
| Alternate | Natural Dispersal |
| Alternate | Discarded Bait |
Regional Impacts
| Ecological Impact | Predation | |
| In Tomales Bay, Carcinus maenas is a less effective predator than the native crab, Cancer antennarius (California Rock Crab), on native (Acanthinucella spirata) and introduced whelks (Urosalpinx cinerea, Atlantic Oyster Drill), resulting in an increased abundance and habitat range of whelks in the inner Bay, where C. maenas better tolerates low salinities (Kimbro et al. 2009). | ||
| Ecological Impact | Trophic Cascade | |
| In Tomales Bay, Carcinus maenas is a less effective predator than the native crab, Cancer antennarius, on native (Acanthinucella spirata, Angular Unicorn Whelk) and introduced whelks (Urosalpinx cinerea, Atlantic Oyster Drill), resulting in an increased abundance and habitat range of whelks in the inner Bay, where C. maenas better tolerates low salinities (Kimbro et al. 2009). The increased abundance of U. cinerea, also more tolerant of low salinity than native whelks has resulted in increased mortality and a near-absence of the native Olympia Oyster (Ostrea lurida). | ||