Invasion
Invasion Description
1st Record: Anacapa Island/CA/Pacific Ocean (6/1/2010, Marks et al. 2015); Santa Barbara Island/CA/Pacific Ocean /1/2010, Marks et al. 2015)
Geographic Extent
1st Record: Anacapa Island/CA/Pacific Ocean (2009; 6/1/2010, Marks et al. 2015; Caselle et al. 2017); Kaplanis et al. 2016); Santa Barbara Island/CA/Pacific Ocean /1/2010, Marks et al. 2015; Kaplanis et al. 2016) Twin Harbor, Santa Cruz Island/CA/Pacific Ocean (2009, Marks et al. 2015); Santa Cruz Island/CA/Pacific Ocean (6/1/2010, Marks et al. 2015; Kaplanis et al. 2016)
Vectors
| Level | Vector |
|---|---|
| Alternate | Hull Fouling |
| Alternate | Natural Dispersal |
Regional Impacts
| Ecological Impact | Competition | |
| In 3 marine protected areas (MPAs) on the coast of Anancapa Island, algal communities resisted the invasion of S. horneri in the oldest MPAs, with more intact kelp forest, but S. horneri was more successful in newest MPAs, and unprotected areas, with more disturbance by recent fishing for sea urchins, and spiny lobsters and California Sheepshead fish (Semicossyphus pulcher), both urchin predators. Fishing for urchin predators reduced overall grazing, favoring competition by native algae (Caselle et al. 2017). | ||