PROTECTION STATUS: Endangered
YEAR PLACED ON LIST: 1970
CRITICAL HABITAT: None; proposed rule 1980
RECOVERY PLAN: 1985
RANGE: A small portion of the upper Santa Clara River drainage in Los Angeles County and the San Antonio Creek drainage in Santa Barbara County
THREATS: Urban development, pollution, mining, predation by nonnative species, water quality degradation, channelization of streams, and groundwater pumping
POPULATION TREND: The threespine population trend is uncertain. Monitoring began in the Angeles National Forest in 2001, where the population appears to be maintaining a stable distribution within the forest. Substantial impacts to the species’ habitat are thought to have occurred in 2003 and 2004 as a result of numerous development projects in the Santa Clarita Valley.