Invasion
Invasion Description
1st Records: Pymouth, Devon/England/English Channel (2004, Arenas et al. 2006); Torquay, Cornwall/England/English Channel (2004, Arenas et al. 2006)
Geographic Extent
Pymouth, Devon/England/English Channel (2004, Arenas et al. 2006); Torquay, Cornwall/England/English Channel (2004, Arenas et al. 2006); Plymouth, Devon/England/Firestone Bay, Plymouth Sound (50 21 3900N, 4 9 3600W); Found in~13 marinas, ~6 natural reefs in Celtic Sea area (Epsteinn and Smale 2017)
Vectors
| Level | Vector |
|---|---|
| Alternate | Hull Fouling |
| Probable | Ballast Water |
| Alternate | Oyster Accidental |
Regional Impacts
| Ecological Impact | Habitat Change | |
| Unlike two of the major native kelps (Laminaria ochroleuca, Saccharina latissima), U. pinnatifida dies off seasonally, as does another native kelp, Saccorhiza polyschides. Undaria pinnatifida supports a less diverse epizoic community than the perennial kelps so its spread may decrease biodiversity (Arnold et al. 2015) | ||
| Economic Impact | Shipping/Boating | |
| Dense fouling of pontoons occurred in marinas in Torquay, England. However, over a period of 7 years, U. pinnatifida did not colonize adjacent shorelines or breakwaters. | ||
| Ecological Impact | Competition | |
| The invasion of Undaria pinnatifida, in Plymouth Sound, is partially inhibited by the presence on native kelp canopies, and favored by disturbance, but U. pnnatifida is capable of establishing itself in intact native communties (De Leij et al. 2017). Removal experiments showed small reductuins in growthperennial native kelps (Laminaria digitata and Saccharina latissima), but 3-6X increase in biomass for the annual kelp Saccorhiza polyschides (Epstein et al. 2019). | ||