Invasion

Invasion Description

1st Record: CA/Sacramento-San Joaquin Delta (1921, Cohen et al. 1995). The initial date of introduction to the watershed is uncertain- various sources report introductions to California in 1891-1895, but there may be confusion with Rock Bass intorductions (Dill and Cordone 1997).

Geographic Extent

CA/Sacramento-San Joaquin Delta (Cohen et al. 1995; Dill and Cordone, 1997; Brown and Michniuk (2007); CA/Suisum Marsh (Matern et al. 2002, rare); CA/North Fork Mokelumne River, Sacramento-San Joaquin Delta (2010, Cavallo et al. 2013)

'Warmouth apparently became well established in the Delta region of the Estuary by the 1940s and is now present in streams of the Central Valley floor and several Sierra Nevada foothill reservoirs (Dill and Cordone, 1997; Moyle, 2002).' (Leidy 2007)