Invasion
Invasion Description
1st Reocrd: Mexico/Baja California; (1961, Whiteside and Murray 2004
Geographic Extent
"Southern California"/CA/Pacific Ocean (1999); Paradise Cove-Point Fermin/CA/Pacific Ocean (Blanchette et al. 2008, ~5-10% of cover in rocky intertidal); Point Fermin, San Pedro/CA/Pacific Ocean (1999, Whiteside and Murray 2004); Smith et al. 2014); Laguna Beach/CA/Shaw's Cove (2010, Smith et al. 2014); Dana Point/CA/Pacific Ocean (2004, Maloney et al. 2006; Smith et al. 2014); Point La Jolla/CA/Pacific Ocean (2004, Maloney et al. 2006); Mexico/Baja California; (1961, Whiteside and Murray 2004); Point Fermin, San Pedro-Scripps Instiute of Oceanography, La Jolla (Pister 2009, natural substrate only, not on riprap); Blue Cavern Onshore State Marine Conservation Area, Santa Catlaina Island/CA/Sotuhern California Bight (Looby and Ginsbirg 2021)
Vectors
| Level | Vector |
|---|---|
| Alternate | Hull Fouling |
| Alternate | Ballast Water |
Regional Impacts
| Ecological Impact | Habitat Change | |
| Caulacanthus okamurae has become a local dominant in mid-intertidal algal turf communities in southern California (Whiteside and Murray 2004; Smith et al. 2014.) Blanchette et al. (2008) found that C. okamurae had an average of ~5-10% cover at sites from Paradise Cove to Point Fermin, but did not note its occurrence elsewhere in a survey of rocky intertidal communities from San Diego to Alaska. At five sites in southern California (Dana Point, Shaw's Cove, Corona del Mar, Point Fermin, and Point Fermin North), C. okamurae often formed dense patches of low turf exceeding 40% cover. This turf displaced macroinvertebrates, such as limpets, periwinkles, and barnacles, but supported an increased number of copepods and ostracods, and of fleshy seaweeds, including Ulva, Gelidium, and Chondracanthus. The dense turf may restrict movements of larger animals, and settlement and feeding of barnacles, but also retains water and reduces desiccation (Smith et al. 2014). | ||