Invasion
Invasion Description
First Record: Chipps Island/CA/Suisun Bay (1993, Cohen and Carlton 1995; Orsi and Ohtsuka 1999)
Geographic Extent
CA/Suisun Bay-Sacramento-San Joaquin Delta (San Francisco Bay) (Cohen and Carlton 1995; Orsi and Ohtsuka 1999); Antioch Pier to Martinez/CA/Suisun Bay (Bouley and Kimmerer 2006); CA/San Pablo Bay to South Bay (1997-1999, Bollens et al. 2011, abundant primarily during periods of low salinity); Bull Island/CA/Napa River (2003-2005, Bollens et al. 2014)
Vectors
| Level | Vector |
|---|---|
| Probable | Ballast Water |
Regional Impacts
| Ecological Impact | Competition | |
| Competition- Limnoithona tetraspina appears to have largely replaced a previous introduction, L. sinensis in the low-salinity region of the San Francisco estuary (Orsi and Ohtsuka 1999), and in the Columbia River, as well. However, interactions between the two species have not been studied. In the San Francisco estuary, L. tetraspina may have been favored by its greater tolerance of brackish water (Ferrari and Orsi 1984; Bouley and Kimmerer 2006). | ||
| Ecological Impact | Food/Prey | |
| Food/Prey- Currently, abundances of L. tetraspina relative to large copepods may be adversely affecting Delta Smelt (Hypomesus transpacificus), which selectively prefer larger copepods, based on feeding experiments (CalFed Science Program 2009, research by Lindsay Sullivan; Slater et al. 2014) The effects of introduced copepods are additionally complex, because of the varying size of the life-stages, and the interaction of different species of fish predators (Sullivan et al. 2016). | ||