Invasion
Invasion Description
1st Record: Damariscotta/ME/Damariscotta River (1982, Dijkstra and Nolan 2011, observed by oyster farmers)
Geographic Extent
Nova Scotia/Minas Basin (4/2015, Vercaemer et al. 2015); off Yarmouth/Nova Scotia/Gulf of Maine (Vercaemer et al. 2015); off Digby Neck/Nova Scotia (2014, Vercaemer et al. 2015); Nova Scotia/Minas Channel (2014, Vercaemer et al. 2015); off Cape Chignecto/Nova Scotia/Bay of Fundy (2014, Vercaemer et al. 2015); Parrsboro/Nova Scotia/Bay of Fundy (10/2013, Moore et al. 2014); ME/Cobscook Bay (Rocky seabed in Cobscook Bay near location of old toll bridge from Eastport (Old Toll Bridge Road) to Perry, ME. Photographed Aug. 6, 2005. Identified by L. Harris, 2005., 2002,USGS Woods Hole Science Center 2003-2007); Bremen Long Island/ME/Muscongus Bay (2006, (2002,USGS Woods Hole Science Center 2003-2007); Damariscotta/ME/Damariscotta River (Dijkstra and Nolan 2011, observed by oyster farmers); Damariscotta/ME/Fort Island Narrows, Damariscotta River (43 deg 53.68 min N lat, 69 deg 35.27 W lon, 1991, USGS Woods Hole Science Center 2003-2007); Maine Department of Marine Resources Docks, Boothbay Harbor/ME/ Boothbay Harbor (2007, MIT Sea Grant 2007); Cape Elizabeth/ME/Dyers Cove, Casco Bay (2010, Massachusetts Office of Coastal Zone Management 2013); Wells Harbor Marina/ME/Wells Harbor (2013, Wells et al. 2014); Back Channel Marina, Portsmouth area/NH/Great Bay (2001); Badger Island Marina, Portsmouth area/NH/Great Bay (2001, Ruiz et al. unpublished data); Main Marina Shipyard, Sounding Pier, Portsmouth area/NH/Great Bay (2001, Ruiz et al. unpublished data); Port Authority, Portsmouth area/NH/Great Bay (2001, Ruiz et al. unpublished data); Fort Point, Newcastle/NH/Great Bay (2002,USGS Woods Hole Science Center 2003-2007); Newington/NH/Piscataqua River (2002, USGS Woods Hole Science Center 2003-2007); Wentworth Marina, Portsmouth/HN/Great Bay (2006, Harris and Dijkstra 2008); Coastal Marine Lab, Portsmouth/NH/Great Bay (2006, Harris and Dijkstra 2008; 2010, Massachusetts Office of Coastal Zone Management 2013); Odiorne Point/NH/Gulf of Maine (2010, Massachusetts Office of Coastal Zone Management 2013); Duck Island, Isles of Shoals/NH/Gulf of Maine (2-03, Bullard et al. 2007); Straitsmouth Island, Rockport/MA/Gulf of Maine (2006, MIT Sea Grant 2011); Hawthorne Cove Marina, Salem/MA/Salem Harbor (2010, Massachusetts Office of Coastal Zone Management 2013); Winter Island, Salem/MA/Massachusetts Bay (2010, Massachusetts Office of Coastal Zone Management 2013); off Cottage Park Road, Winthrop, MA/Boston Harbor (2006, USGS Woods Hole Science Center 2003-2007); Black Falcon Terminal. Boston/MA/Boston Harbor (2008, MIT Sea Grant 2011); Green Harbor Marina, Marshfield/MA/Cape Cod Bay (2013, Wells et al. 2014);; Brewers Plymouth Marina/Plymouth Harbor, Cape Cod Bay (2010, Massachusetts Office of Coastal Zone Management 2013); Sandwich/MA/tidepool at mouth of Cape Cod Canal (2003), 41 deg 46.42 min N lat, 70 deg 29.30 min W lon, USGS Woods Hole Science Center 2003-2007); Sandwich Marina/MA/Cape Cod Bay (2000, MIT Sea Grant 2003-2007; USGS Woods Hole Science Center 2003-2007); Dennis/MA/Sesuit Harbor, Cape Cod Bay (2008, MIT Sea Grant 2011); Provincetown/MA/Cape Cod Bay (2003, 42 deg 02.95 min N lat, 70 deg 10.85 min W lon, USGS Woods Hole Science Center 2003-2007, MIT Sea Grant 2003-2007); MA/Stellwagen Bank (1998, Bullard et al. 2007); MA/Tillies Bank (1996, Bullard et al. 2007) Georges Bank; November, 2003; in a 6 sq mi area centered on 41 deg 58 min N lat, 67 deg 31 min W lon; water depth 48 m, (157 ft). Source: P. Valentine, J. Collie, R. Reid. (USGS Woods Hole Science Center 2003-2007; Bullard et al. 2007; Kaplan et al. 2017) Absent in a field survey of New Brunswick waters adjacent to Eastport ME (2009, Martin et al. 2010).
Vectors
| Level | Vector |
|---|---|
| Alternate | Hull Fouling |
Regional Impacts
| Ecological Impact | Competition | |
| In Portsmouth Harbor, by 2003-2006, colonial tunicates including D. vexillum replaced the mussel Mytilus edulis (1979-1982) as the dominant species in fouling communities (Dijkstra and Harris 2009). | ||
| Ecological Impact | Habitat Change | |
| In Portsmouth Harbor, by 2003-2006, colonial tunicates including D. vexillum replaced the mussel Mytilus edulis (1979-1982) as the dominant species in fouling communities (Dijkstra and Harris 2009). A major functional change is that while mussel shells provided a year-round structure on the substrate, available to settlement by other organisms, colonial tunicates are more resistant to secondary settlement, and die off seasonally, creating large areas of bare substrate which can be colonized by other organisms (Dijkstra and Harris 2009). Didemnum vexillum can make Sea Scallops (Placopecten magellanicus) more vulnerable to predators by fouling their shells and decreasing their swimming speed (Dijkstra and Nolan 2011). On Georges Bank, extensive cover of D. vexillum is negatively correlated iwth abundance of P. magellanicus, barncles, tube anemones, Cerianthus, to sea urchins (Strongylocentrotus droebachiensis). Didemnum vexillum is considered a major driver of biodiversity decline on Georges Bank. Its effects are strongest on areas disturbed (by trawling (Kaplan et al. 2017). | ||
| Economic Impact | Fisheries | |
| Didemnum vexillum was reported fouling aquaculure sites in Maine (Carman et al. 2010; Bullard et al. 215). | ||
| Ecological Impact | Food/Prey | |
| Increasing abundance of the introduced colonial tunicates Didemnum vexillum and Diplosoma listerianum has resulted in population growth of the native Bloodstar starfish Henricia sanguinolenta (Dijkstra et al. 2012). | ||
| Ecological Impact | Trophic Cascade | |
| Increased abundance of the Bloodstar starfish (Henricia sanguinolenta), supported by growing populations of Didemnum vexillum and Diplosoma listerianum, has resulted in increased predation and near-disspapearance of the cryptogenic sponge Halichondria panicea (Dijkstra et al. 2012). | ||