Invasion
Invasion Description
1st Record: CA/Tomales Bay (Bonnot 1935, cited by Carlton 1979)
Geographic Extent
CA/Tomales Bay (Bonnot 1935, cited by Carlton 1979); Double Point/CA/Tomales Bay (Haydock 1964, cited by Carlton 1979); Millerton Point/CA/(Haydock 1964, cited by Carlton 1979
Vectors
| Level | Vector |
|---|---|
| Probable | Oyster Accidental |
Regional Impacts
| Economic Impact | Fisheries | |
| An area of bay bottom used to hold Eastern Oysters (Crassostrea virginica), for sale, was 'heavily infested' with Atlantic Oyster Drills (Carriker 1955). Predation on cultured Crassostrea gigas is likely, but not reported (Carriker 1955). | ||
| Ecological Impact | Predation | |
| Urosalpinx cinerea is a major predator of the native Olympia Oyster (Ostrea lurida) in Tomales Bay, together with the native Acanthinucella spirata (Angular Unicorn Whelk). In Tomales Bay, predation by the large native Pacific Rock Crab (Cancer productus) excludes U. cinerea from the outer Bay, which is dominated by the better-defended native whelk. The Atlantic Oyster Drill is most common in the inner Bay, where it tolerates the low salinity, better than the native crab and whelk. The introduced Green Crab (Carcinus maenas) is the major predator in the inner Bay, but it is less effective at eating the introduced drill than the native crab, so U. cinerea reaches high densities and causes high mortality of Olympia Oysters (Kimbro et al. 2009; Cheng and Grosholz 2016). Ocean acidification may increase the predatory impact of U. cinerea on O. lurida in Tomales Bay, because the oysters raised under acidified conditions were smaller and more vulnerable to the drills (Sanford et al. 2013). In another study, Urosalpinx cinerea was a major predator on Olympia Oysters (Ostrea lurida), especially on the eastern side of the Bay, when low salinities and high temperatures, reduced predation by native Rock Crabs (Cancer productus). Climate warming my increase predatpory impacts by this snail (Cheng et al. 2016). Native predatory snails (Acanthinucella spirata) appeared to have little impact on Olymbic Oyster populations in this tuday (Cheng and Grosholz 2016). | ||