Here are some things you should know about nutria. They are a semiaquatic South American rodent a bit smaller than a beaver. Females can give birth three times a year and have up to 12 babies each litter. They are really good at tearing up crops, burrowing tunnels into levees, and other destructive behavior that is tough on farmers. And they've been discovered in California's San Joaquin Valley, a major food-producing area.
All of these facts spell huge problems for California officials tasked with the complicated task of removing these rodents from the state.
Nutria are already an invasive species wreaking havoc in Louisiana, Oregon and Maryland. They can quickly turn a wetland into a mudflat as they chomp down on plants. So when the species was spotted in Merced County, California, in March of 2017, officials knew exactly how worried they should be.
"They can consume up to 25% of their body weight in above- and below-ground vegetation each day, but they waste and destroy up to 10 times as much, causing extensive damage to the native plant community and soil structure, as well as significant losses to nearby agricultural crops," notes the California Department of Fish and Wildlife (CDFW).
Equal opportunity offenders
Nutria have enormous potential not only to damage the infrastructure critical to delivering water to cities and farms, but they also threaten wetlands and riparian habitat as well as existing restoration projects. They can carry tuberculosis, septicemia, tape worm and other parasites that can contaminate water supplies. They are certainly not a welcome visitor, and they can quickly become an expensive problem.
"Within five years, the state estimates there could be nearly a quarter million nutria chewing up California's endangered wetlands," reports The Sacramento Bee.
Since they were discovered in California in 2017, more than 700 nutria have been trapped and killed.
"Almost every female we've caught has been pregnant. They're incredibly prolific, which is why we have to get on it quickly," said Peter Tira, a spokesman for CDFW, told the Los Angeles Times in February. "They're a threat to our multibillion-dollar agricultural economy, and they're a public safety threat. If they get entrenched in the [San Joaquin River] Delta, they pose a huge threat to our water. It would be hard to get them out of there, and it would have consequences for the whole state."
In an effort to get ahead of the invasion, CDFW has received $10 million in 2019 in state funds to eradicate nutria. Another proposed bill would award $7 million to CDFW over five years to combat the rodents' spread, reports SF Gate.
It will take time and a significant amount of effort and funding, but officials feel confident they can get a handle on the nutria problem. And farmers are keeping their fingers crossed that the rodents don't advance further into the delta.
”It would be devastating," Merced County farmer Stan Silva told KQED. "They can basically ruin the ag industry here — they get in your fields, burrow into your canal ways, your waterways."
Editor's note: This story has been updated since it was published in March 2019.