By Vicky Boyd

As the number of nutria trapped continues to climb, California Department of Fish & Wildlife officials with the eradication effort said gaining access to private property will be imperative to quashing the rodent invasion. "It's going to be key, I know right now," said Peter Tira, CDFW spokesman. "Basically, we'll not be able to eradicate nutria unless we get every single one. If there's a source population on private property, we'll not be able to eradicate them."

While Farm Bureau supports these efforts, there needs to be some additional safeguards for our landowners that need to be in place. SJFB will be sending updates in the Friday Review, But dealing with private property is only one of many challenges the state faces in trying to eradicate nutria, which breed prolifically and could potentially damage the state's waterways and infrastructure. Other hurdles include securing funding and moving quickly during a narrow window of opportunity for eradication.

Under California statutes, CDFW representatives cannot enter private property for activities, such as nutria surveying and trapping, without first receiving written permission from the landowner.

That said, the department recently mailed about 7,000 requests for temporary private property access to landowners in a six-county region living near wetlands, the Delta and within about 2.5 miles of the San Joaquin and Merced rivers and their major tributaries. About 400 landowners have already given their permission, with some including gate codes. A few have made special requests, such as calling beforehand so they can put their dogs or other animals inside.

"We'll work to accommodate special requests," Tira said.

To drive home the importance of private property as nutria habitat, he used an example of a large ranch near Newman. After the department was granted access permission, state trappers removed more than 50 nutria from one pond. All of the nutria surveying and trapping is done free of charge to the landowner.

"Pretty much anywhere there's permanent summer water, there will be nutria," Tira said.

Mary Hildebrand, who farms in the south Delta, said she had received one of the CDFW letters and had already returned it with a requirement to always call beforehand.

"But I think it's important that we cooperate because it's going to be very difficult to eradicate, if it's even possible at all, even with cooperation," said Hildebrand, also a South Delta Water Agency board member.

"They're obviously trying hard to have the temporary entry permits be acceptable. You can add any stipulation or restrictions you want, and either party can cancel it with a written notice prior to the one-year expiration." Roberts Island farmer David Strecker, who has described nutria as a "20-pound angry gopher that burrows into levees," had also received a CDFW letter seeking property access. But he was first going to talk to some of the area reclamation districts.

"I'm curious if it's more important to be on land or would access on the waterways give them a better view," Strecker said. "I think a lot of the main waterways could be accessed better via water.

"I'm more concerned about some of the little sloughs or the smaller rivers where there's a lot of vegetation or the land areas within the main levee system. Anywhere within the primary zone of the Delta, (nutria) are probably going to be found."

New Stockton office

Citing the importance of the Delta, CDFW planned to open an office on July 1 in Stockton that will serve as the region's nutria eradication headquarters. Before that, biologists had been working and training solely out of Los Banos.

Having the Stockton office also will allow wildlife biologists to conduct boat surveys from the water and access riparian areas not easily accessible on foot, Tira said.

Currently, CDFW does not have a dedicated nutria eradication budget and is having to redirect funds and personnel from other programs. As a result, it has sought grants to help underwrite what likely will be a multi-year effort.

Already, the department has received $1.2 million from Proposition 1 water bond funds to be spread over three years. It also received a $600,000 grant from the California Wildlife Conservation Board. 

With the first discoveries, Fish and Wildlife put together an interagency Nutria Response Team to draft an eradication plan. Because nutria have a steep reproductive curve, department officials say they have a narrow eradication window before rodent numbers grow out of hand.

Following Chesapeake Bay efforts

California officials have been in close communication with counterparts in Maryland who successfully eradicated nutria from the Chesapeake Bay area. That state spent more than $15 million to trap more than 14,000 invasive rodents. They have not confirmed a single nutria in the past 2.5 years.

Nutria eradication consists of three phases. Six teams of two biologists each conduct surveys on 40-acre grids along wetland corridors. They check for nutria sign, such as "eat outs" – places where nutria have eaten swaths of aquatic vegetation – or scat.

If there's reason to believe nutria are there, biologists then set up game camera traps or hair snares on mounds on which nutria prefer to feed and groom. Pieces of hair can be analyzed to determine whether it is from nutria or other wetland dwellers, such as muskrat.

If nutria are confirmed, the department sends out trapping crews, which use live-catch traps baited with sweet potatoes. Doreva Produce of Livingston has been donating the sweet potatoes.

Because of Proposition 4, the voter-passed initiative that banned leg-hold traps and neck snares, state trappers are limited in their methods, Tira said. 

Biologists conduct necropsies, akin to an autopsy of animals, on each nutria taken so they can determine gender, age and reproductive status. So far, most of the females collected have been pregnant, he said.

Joining the eradication effort will be two nutria dogs, Star and Trigger, which were used successfully by U.S. Department of Agriculture's Wildlife Services in the Chesapeake Bay nutria eradication program. The dogs are able to detect nutria scent and scat, and can cover wetlands more quickly than human surveyors, Tira said. A five-month $160,000 state contract for three Wildlife Services trappers also was recently approved.

Nutria in San Joaquin County

San Joaquin County is one of six counties in the state in which the semi-aquatic rodent, which some have compared to a giant swamp rat, has been confirmed since it was initially discovered in 2017. The others are Madera, Merced, Fresno, Stanislaus and Tuolumne counties.

An A-rated agricultural pest by the California Department of Agriculture, nutria can burrow 3 to 18 feet deep, and the burrows can extend up to 150 feet into a bank.

"The obvious big issue is we don't want to cause any issues with our infrastructure in the Delta," said San Joaquin County Ag Commissioner Tim Pelican. "They eat about 5 pounds of food per day. They eat stuff at the basal part of the plant so they're destroying at least five times more than they're eating."

Since a farmer on Roberts Island brought a dead nutria into the San Joaquin County Agriculture Commissioner's office in April – marking the first time the pest had been found in the county – at least one other confirmed sighting of the invasive rodent has been made, Pelican said.

A Lathrop resident called animal services about an unidentified animal under her car. The animal control officer came out, couldn't identify the creature, snapped a picture and returned it to the river.

"There have been two sightings and we know there's one swimming around out there," Pelican said. The Lathrop find was about a half mile from any waterway.

So far, the state has trapped and dispatched a total of 166 nutria in a six-county region as of June 22. Pelican cited the additional natural challenges California will face against the nutria.

"We have no natural predators here in California," he said. "In the Chesapeake Bay, one of the things they had there was the cold weather because they can't survive the cold well. At least in Louisiana, they have alligators."

Pelican also pointed to the $3 to $5 per-tail bounty offered by the Department of Wildlife and Fisheries in Louisiana, where nutria are endemic. Since 2002, Louisiana has more than $24 million on bounties and has not reduced the overall nutria population. At best, the program has only kept rodent numbers in check, Pelican said.