Procambarus clarkii
The closely related "Taricha torosa", the California newt, is currently a California Special Concern species (DFG-CSC). Some populations have been greatly reduced in southern California coastal streams due to the introduction of non-native, invasive species and human habitation. The mosquitofish ("Gambusia affinis") and red swamp crayfish ("Procambarus clarkii") have caused the greatest reduction in newt populations.