Species Regional Summary
Didemnum vexillum
Great Bay ( N130 )

Invasion History Vectors Impacts References

Invasion

Invasion Description

Portsmouth area/NH/Great Bay (2001, Ruiz et al. unpublished data)

Geographic Extent

Back Channel Marina, Portsmouth area/NH/Great Bay (2001, Ruiz et al., unpublished data); Badger Island Marina, Kittery/NH/Great Bay (2001, Ruiz et al. unpublished data); Main Marina Shipyard, Sounding Pier, Portsmouth area/ME/Great Bay (2001, Ruiz et al. unpublished data); Port Authority, Portsmouth area/NH/Great Bay (2001, Ruiz et al. unpublished data); Fort Point, Newcastle/NH/Great Bay (2002,USGS Woods Hole Science Center 2003-2007); Newington/NH/Piscataqua River (2002, USGS Woods Hole Science Center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 (2003; MIT Sea Grant 2006; MIT Sea Grant 2009; 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); University of New Hampshire Coastal Marine Laboratory, Portsmouth/NH/Great Bay (2018, reeport Marina, Freeport/ME/Casco Bay (2018, Commonwealth of Massachusetts, Executive Office of Energy and Environmental Affairs, Office of Coastal Zone Management 2020); Port Harbor Marina, Portland/ME/Casco Bay (2018, Commonwealth of Massachusetts, Executive Office of Energy and Environmental Affairs, Office of Coastal Zone Management 2020)

Vectors

Level Vector
Probable Hull Fouling

Regional Impacts

Ecological ImpactCompetition
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 ImpactHabitat Change
In Portsmouth Harbor, by 2003-2006, colonial tunicates including D. vexillum replaced the mussel Mytilus edulis as the dominant species in fouling communities (Dijkstra and Harris 2009). A major functional change occured because while mussel shells provided structure, which other organisms can settle upon, colonial tunicates are more resistant to secondary settlement.  However, colonial tunicates die off seasonally, creating large areas of bare substrate which can be colonized by other organisms (Dijkstra and Harris 2009).
 

References

Full Reference List for Didemnum vexillum

  • Nemesis (current)
  • Marine Invasions Lab
  • Partner Portals
    Nemesis California Panama Galapagos Cocos Island NP JTMD
    Archived Projects
    Chesapeake
  • Browse Species
    Taxonomic Groups All Species
  • Browse Regions
    States
    Alaska
    Bioregions & Bays
  • News
  • login

Direct questions and comments to nemesis@si.edu.

©