On the Eel River, the most hated fish is a California native — but a stranger nonetheless

MENDOCINO CO., 6/9/26 — Every summer a line of volunteers in masks and wetsuits floats down the South Fork Eel, shoulder to shoulder across the current, counting the one fish almost everyone on the river wants gone.

They are counting Sacramento pikeminnow, and this is the 11th year they’ve done it. The Eel River Recovery Project runs the dive every summer along a 12-mile stretch of the South Fork, from Rattlesnake Creek down to Standish Hickey State Recreation Area — two six-mile reaches, six divers, the whole run knocked out in a day when enough volunteers show up. They count only fish over four inches and sort them by size, and they also log the young salmon and steelhead they pass on the way.

“Like it or not, we’re in charge of evolution, and we will never get rid of them,” said Pat Higgins, who runs the recovery project out of Loleta and has led the count since it started in 2016. “But if we don’t suppress them, we’re going to get more pikeminnow and fewer native fish.”

The pikeminnow is the most reviled animal in the Eel. Someone dumped it into Lake Pillsbury in 1979 — a bait-bucket introduction, illegal — and by 1986, it had spread through the whole basin, its numbers climbing into the millions. A torpedo of a fish, it eats juvenile salmon and steelhead on a river fighting to bring those runs back.

It has crowded out more than salmon: the native sucker that grazes algae off the rocks is now rare in the South Fork, Higgins said, and so is the sculpin that lives down in the cobbles like a miniature lingcod.

What the dive has shown over 11 years is that the fish doesn’t decline on a straight line. It rides the weather. The first three counts ran around 1,100, 1,400 and 1,200. Then the floods of 2019 blew the small fish out to the ocean and the count fell to the 600s. Higgins figured the population was headed down for good. It wasn’t. After 2020 — the fifth-driest year on record — the next count came back at 6,600.

“Tenfold increase,” Higgins said. He’d been wrong about why, too. The books all said pikeminnow spawn in spring, in warm creeks. What he learned is that they also spawn in the fall, in the main river channel, which is how they shrugged off a dry year that should have set them back. The count eased to around 4,500 after that. This winter brought two big high-water events, one near Christmas and one at the end of February, so Higgins expects the 2026 count to cycle back down.

Pikeminnow like it hot

Temperature is the lever. Pikeminnow do best at about 82 degrees, Higgins said — they thrive when the Eel runs hot, which it didn’t, historically. The river warmed after the 1964 flood packed some 60 feet of sediment into the main stem where the South Fork comes in, filling the deep pools and spreading the water thin and warm. The pikeminnow arrived 15 years later into exactly the river they like.

Here is the part that complicates the hatred: the Sacramento pikeminnow is not an invader. It’s a California native. Drop over the ridge to the Russian or the Salinas, or east into the Sacramento-San Joaquin, and the same species is a longtime local.

Peter Moyle, the dean of California fish biologists, calls it “resilient” and has written that its qualities as food are “underappreciated” — “a common food of Native Americans.” The state’s record of tribal fish use lists it as a traditional food of Pomo people. Villain or native depends on which side of the divide you’re standing on.

The fish even shed a slur to get its name. For most of the last century it was called “squawfish.” The American Fisheries Society renamed all four squawfish species “pikeminnow” in 1999, and in 2021 the Interior Department ordered the word scrubbed from federal maps.

Tasty snack or mercury minefield?

All of which raises a question nobody around here has answered. You’re urged to kill them — so can you eat them?

In the Central Valley the answer is mostly no: pikeminnow are long-lived top predators that build up mercury, and state health officials warn women under 50 and children not to eat them from the Sacramento River and the northern Delta, along with the Feather and American rivers.

But those are Gold Country waters, fouled by a century of mercury mining.

The Eel is not a mining watershed, and no one has published a mercury advisory for its pikeminnow. Higgins draws the same line: a pikeminnow out of Clear Lake or Cache Creek would carry mercury, he said, “but these haven’t been in those waters in a long time.”

So the fish everyone wants gone might be dinner — but they’re bony enough that you have to score the fillets to cut the bones before they’ll fry up into anything worth eating.

A colder river would solve the problem

Mostly, though, the river fights them. Beyond the count, crews now spear pikeminnow as they dive, and a weir near Piercy intercepts the big adults as they drop downstream and try to come back — work done with tribal partners, UC Berkeley and CalTrout under state permits. The fish over 16 inches are almost all females, Higgins said, and the heaviest predators on native fish.

What he’s after isn’t a fish-free river. It’s a colder one. Moyle has argued that if the Eel were cooled back down — its tributaries shaded, the sediment that warms and widens it held back — salmon, steelhead and pikeminnow could share it, the way they’ve shared the Russian and the Sacramento for as long as they’ve coexisted there. Pulling Scott Dam and draining the Pillsbury reservoir, where the pikeminnow first took hold and still breed in force, is expected to cut off the supply.

Until then, the divers go back in. In a few weeks they’ll float the South Fork again, counting the fish nobody wants — the native everyone here treats as a stranger.