Genetic Study Reveals Human Introduction of Invasive Nutria to California
Genetic testing by the California Department of Fish and Wildlife indicates nutria were deliberately reintroduced to California from central Oregon. The invasive rodents, first eradicated in the 1970s, were rediscovered in 2017 in San Joaquin Valley. Researchers built a global DNA database using museum specimens, including one from Butte County Weights and Measures. Modern nutria descend from a single lineage, unlike historical populations with diverse origins. Officials speculate motives could range from vegetation control to malice. Eradication efforts since 2017 have removed 7,841 animals across Central Valley wetlands. The state spends $5 million annually combating threats to levees and dams. Under California law, property owners may kill nutria but must report kills immediately.
Key facts
- Nutria were rediscovered in California in 2017 after being eradicated in the 1970s.
- Genetic testing links California's nutria to populations in central Oregon.
- The California Department of Fish and Wildlife announced findings on April 7.
- Researchers published a study in Evolutionary Applications in November.
- Eradication efforts have captured 7,841 nutria since 2017.
- California spends about $5 million annually on nutria eradication.
- Nutria first entered the U.S. at Elizabeth Lake, California, in 1899 for the fur trade.
- Property owners may kill nutria damaging property but must report kills to the state.
Entities
Institutions
- California Department of Fish and Wildlife
- Butte County Weights and Measures Department
- Tufts University
- U.S. Fish and Wildlife Service
Locations
- California
- San Joaquin Valley
- Oregon
- Elizabeth Lake
- Central Valley
- South Coast
- Merced County
- Sacramento-San Joaquin Delta
- Longmont
- Colorado