Invasion
Invasion Description
1st Record: Provincetown/MA/Cape Cod Bay (1872, Glude 1955; Almaca 1963)
Geographic Extent
Provincetown/MA/Cape Cod Bay (1872, Glude 1955; Almaca 1963); Sandwich/MA/Cape Cod Bay (2000, MIT Sea Grant 2003); Barnstable/MA/Cape Cod Bay; Manomet Point/MA/Cape Cod Bay (1902, Bryant 1906); Plymouth/MA/Plymouth Harbor; Duxbury/MA/Plymouth Harbor (2002, MIT Sea Grant 2003); Marshfield/MA/Cape Cod Bay (O'Connor 2013); Welfleet/MA/Blackfish Creek (Coerdale et al. 2013)
Vectors
| Level | Vector |
|---|---|
| Alternate | Dry Ballast |
| Alternate | Hull Fouling |
| Alternate | Natural Dispersal |
Regional Impacts
| Ecological Impact | Predation | |
| Carcinus maenas was the most voracious predator of egg capsules of Ilyanassa obsoleta (Brenchley 1982). | ||
| Ecological Impact | Competition | |
| Caging experiments show that predation by Carcinus maenas reduce abudances of the Marsh Crab (Sesarma reticulum) by evicting the smaller crabs from their burrows. The Green Crabs use these burrows as a refuge from predation (Coverdale et al. 2013). | ||
| Ecological Impact | Trophic Cascade | |
| Caging experiments show that compettion by Carcinus maenas reduces abudances of the Marsh Crab (Sesarma reticulum) by evicting the smaller crabs from their burrows, and exposing the Marsh Crabs to predation. The reduction in Marsh Crab hebivory has resulted in increased growth and recovery of Spartina alterniflora saltmarshes. The previous decline of the Spartina marshes has been attrributed to an increase in the herbivorous Marsh Crab, triggered by heavy fishing fot predatory fishes (Coverdale et al. 2013). | ||