Here’s some good news for wild salmon lovers: Right before Thanksgiving, the U.S. Environmental Protection Agency (EPA) announced new restrictions on pesticide use in California. The first-of-its-kind move is aimed at protecting salmon and steelhead trout native to the state’s rivers and it sets the stage for protections that could benefit salmon along the Pacific coast.

Americans eat more salmon than any other fresh fish. About two-thirds of that salmon is farmed outside the U.S., but the remaining third is Pacific salmon caught primarily off the coasts of Alaska, Washington, Oregon, and California. While the U.S. commercial Pacific salmon catch clocked in at more than 1 billion pounds last year, a number of Pacific Northwest salmon species are now protected under the Endangered Species Act (ESA).

And, as it turns out, those fish are hard hit by agricultural chemicals.

“Pesticides have multiple effects on salmon,” explains Glen Spain, Northwest Regional Director of the Pacific Coast Federation of Fishermen’s Associations (PCFFA). Chemicals that run off of agricultural fields and end up in streams and rivers can harm salmon neurologically, disrupting the navigation and homing instincts crucial for species that migrate to the ocean and return to their home rivers years later to spawn. Pesticides can also impair the fish’s development and reproduction, in ways that reduce their survival.

The new EPA restriction is “unprecedented,” said Jim Milbury, public affairs officer at the National Oceanic and Atmospheric Administration (NOAA). It was put in place under the Biological Opinion that’s part of the ESA listing though which NOAA Fisheries now protects threatened and endangered salmon. It is also the first of several dozen pesticides EPA and NOAA Fisheries have been reviewing under these ESA obligations. Explaining the announcement, EPA spokesperson Suzanne Skadowski and biologist Patti TenBrook said that action on other pesticides under this ESA review are expected to follow.

“This action also supports EPA’s commitment to minimize pesticide pollution in the San Francisco Bay Delta,” said Jared Blumenfeld, EPA’s Regional Administrator for the Pacific Southwest.

The chemical in question is thiobencarb, an herbicide used in California’s $5 billion rice industry. The restrictions on thiobencarb, explains EPA, are the result of litigation brought against EPA and NOAA Fisheries by organizations that include the PCFFA, Washington Toxics Coalition, and Northwest Center for Alternatives to Pesticides. The suit, filed in 2001, contended that the EPA had violated the Endangered Species Act by failing to take steps to ensure that use of more than four dozen different pesticides would not jeopardize the survival of threatened and endangered Pacific Northwest salmon. In 2002, the court ruled in favor of the groups and ordered the EPA to evaluate the impact of these pesticides on the listed salmon and steelhead–fish native to rivers in Idaho, Washington, Oregon, and California.

The new rule will affect pesticide use in the 14 California counties where rice is grown. Nearly all of California’s 550,000 acres of rice production takes place in the Sacramento Valley, which is home to threatened and endangered Chinook and coho salmon and to steelhead trout.

Thiobencarb is used in the spring when rice is starting to grow, a time of year “that’s also peak migration for Sacramento fall Chinook,” explains Joel Kawhara who fishes commercially for salmon off the Washington and Oregon coasts. This means it would be present in the water when young, just-hatched fish are beginning their trip to the ocean. At this stage of life, salmon are particularly vulnerable to environmental stress and to what Kawahara calls “sublethal effects” that can have a big impact on their survival.

“Wild seafood is our last really authentic food,” said Jeremy Brown, a commercial fisherman based in Bellingham, Washington. But, he added, they are also “in the line of fire” from pesticide use. The ESA listings are designed to protect the most vulnerable fish, or “weakest stocks,” added Brown. But the health of those fish and their habitat affects what he and other fisherman can catch up and down the Pacific Coast.

Whether it’s from rice growing in California or industry in Washington state, keeping pollutants out of the water is an essential part of protecting one of the last foods that is not produced industrially, said Brown. “And more and more, we’re learning that this is the kind food we should be eating.”