Invasion
Invasion Description
1st Record: Isles of Shoals/NH-ME/Gulf of Maine (1983, Carlton and Scanlon 1984)
Geographic Extent
Rye Ledge/NH/Gulf of Maine (1985, Mathieson et al. 2003); Isles of Shoals/NH-ME/Gulf of Maine (1983, Carlton and Scanlon 1985)
Vectors
| Level | Vector |
|---|---|
| Alternate | Hull Fouling |
| Alternate | Natural Dispersal |
| Alternate | Fisheries Accidental (not Oyster) |
| Alternate | Oyster Accidental |
Regional Impacts
| Ecological Impact | Competition | |
| Codium fragile invades kelp beds after disturbances, and displaces kelps and inhibits kelp recruitment. It exploits the fouling and killing of kelps by the introduced bryozoan Membranipora membranacea (Levin et al. 2002). In shallow waters along the Isle of Shoals, there was a gradual shift from kelps to Codium and to an opportunistic red alga community (Harris and Tyrell 2001). | ||
| Ecological Impact | Habitat Change | |
| Codium fragile replaces kelp canopy with less favorable habitat, and supports fewer juvenile fishes (Cunner, Tautogolabrus adspersus) (Levin et al. 2002). Around the Isles of Shoals, NH-ME, from the 1979 to 2015, there has been a trend of replacement of kelps and other larger brown seaweeds, by smaller, bushier red seaweeds (Bonnemaisonia hamifera, Dasysiphonia japonica, and Neosiphonia spp.) and Codium fragile, increasing the structural complexity of the environment, and the abundance and diversity of meso-sized invertebrates (Dijkstra et al. 2017). | ||
| Ecological Impact | Food/Prey | |
| The native snail Lacuna vincta occurred in lower density on Codium fragile than on the native kelp Laminaria saccharina. In experiments, feeding and growth was reduced in L. vincta on Codium, compared to Laminaria (Chavanich and Harris 2004). Codium fragile was a less-preferred food of the Green Sea Urchin Strongylocentrotus droebachiensis (Prince and Leblanc 1993) The herbivorous saccoglossan sea-slug feeds on C. fragile, and can control the seaweed's populations (Harris and Adams 2005). | ||