"The destructive invasive swamp rodents known as nutria are officially on the doorstep of one of the state's most critically important waterways.
State wildlife officials announced Tuesday that a nutria was killed on agricultural land west of Stockton in San Joaquin County. It's the farthest north the species has been confirmed of the 32 nutria killed so far in California since their discovery in March 2017. The confirmed kill puts the South American rodents on the edge of the Sacramento-San Joaquin Delta.
State and federal wildlife and water officials fear nutria will get a foothold in the Delta's ecologically fragile network of sloughs and rivers. The Delta is the heart of California’s flood-control and water distribution system, supplying water to 25 million Californians and millions of acres of Central Valley farmland."