Invasion
Invasion Description
1st Record: Fox Point/NH/Great Bay (1981, Berman et al. 1989)
Geographic Extent
Fox Point/NH/Great Bay (1981, Berman et al. 1989); Newcastle/NH/Great Bay (Blezard 1998); Coast Guard Pier, Newcastle/NH/Great Bay (2003, MIT Sea Grant 2003); Wentworth Marina, Portsmouth/HN/Great Bay (2006, Harris and Dijkstra 2008); Coastal Marine Lab, Portsmouth/NH/Great Bay (2003, MIT Sea Grant 2003; 2006, MIT Sea Grant 2009; Harris and Dijkstra 2008; 2010, Massachusetts Office of Coastal Zone Management 2013); Great Bay Marina, Newington/NH/Great Bay (2006, Harris and Dijkstra 2008); Jackson Estuarine Lab, Adams Point/NH/Great Bay (Harris and Dijkstra 2008); Odiorne Point/NH/Gulf of Maine (2010, Massachusetts Office of Coastal Zone Management 2013)
Vectors
| Level | Vector |
|---|---|
| Probable | Hull Fouling |
Regional Impacts
| Ecological Impact | Competition | |
| B. violaceus was the most abundant colonial tunicate on fouling plates in Portsmouth Harbor in 2003-2005, partially replacing B. schlosseri, the previous dominant colonial tunicate (Dijkstra et al. 2007). In Portsmouth Harbor, by 2003-2006, B. violaceus and to a lesser extent, D. vexillum replaced the mussel M. edulis (1979-1982) as the dominant species in fouling communities (Dijkstra and Harris 2009). | ||
| Ecological Impact | Habitat Change | |
| In Portsmouth Harbor, by 2003-2006, B. violaceus and to a lesser extent, D. vexillum replaced the mussel M. edulis (1979-1982) as dominant species in fouling communities (Dijkstra and Harris 2009). A major functional change is that while mussel shells provide structure, available for settlement and colonization by other organisms, the 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). | ||