Checking the weir on SF Eel River. Photo by Mike Wier courtesy of CalTrout.

The Good Fight: Beyond Trout

Fly fishing has long been associated with the pursuit of trout and salmon, but there is a growing appreciation for the challenge of targeting less celebrated species. Among these is the Sacramento pikeminnow (Ptychocheilus grandis), a fish often dismissed as a “junk fish” but one that offers a unique angling experience.

In the fishing community, the term “junk fish” is sometimes used to describe species that are perceived as less desirable or less sporting than trout, salmon, or other well-known game fish. Sacramento pikeminnow have historically fallen into this category, largely due to their reputation as predators of juvenile salmon and trout. This perception is rooted in the fact that large pikeminnow are opportunistic feeders known to consume a variety of prey–including other fish– which has earned them the ire of anglers and those working to recover those species.

However, this label is unfair and overlooks the intrinsic qualities that make pikeminnow a worthy target for fly anglers. They are aggressive fighters that are a challenge on a fly rod and abundant in many waterways. In the warm summer months, they offer ample opportunity for anglers looking to broaden their horizons beyond the traditional trout streams.

SACRAMENTO PIKEMINNOW BASICS

Understanding the life history of the Sacramento pikeminnow is essential to appreciating their value and role in the ecosystem. Pikeminnow are native to several watersheds in Central California, including the Sacramento-San Joaquin River system, Pajaro and Salinas Rivers, the Russian River, and the upper Pit River and Clear Lake basin. Each river shares a historic connection to the Sacramento-San Joaquin River system. The Russian River, for example, shares many of the same species as the Sacramento-San Joaquin and is thought to have historically been connected to the Clear Lake drainage.

Sacramento pikeminnow were once commonly referred to as “squawfish,” a term now recognized as outdated. In 1999, the American Fisheries Society officially renamed them to “pikeminnow” to promote culturally respectful language and to reflect a broader effort to honor indigenous cultures that stewarded and relied on the species for thousands of years.

Pikeminnow can grow quite large, with large adults reaching lengths of 24 inches or more and weighing 10 pounds. They are adaptable, thriving in a range of habitats from slow-moving rivers and reservoirs to fast-flowing streams, though they tend to prefer deep, calm pools in the relatively warm mainstems of rivers. Pikeminnow are also long-lived, with some individuals surviving for over a decade. Their lifecycle includes distinct stages, beginning with a spawning migration in the spring when water temperatures rise. Eggs hatch into larvae, which eventually develop into juveniles and then mature adults. Juveniles and sometimes adults tend to congregate in schools of similar sizes with smaller fish holding in shallower water.

Far from being a “junk fish,” pikeminnow offer a challenging angling experience. Photo by Zac Reinstein

One of the most fascinating aspects of pikeminnow biology is their adaptability in diet. While juveniles primarily feed on invertebrates, adults are known for their piscivorous (fish-eating) tendencies. Pikeminnow will also eat lamprey, frogs, crayfish, and even small turtles. This adaptability allows them to thrive in diverse environments and conditions.

Despite their generally poor reputation amongst anglers, as apex predators pikeminnow help regulate the populations of smaller fish and invertebrates, contributing to the overall balance of the aquatic food web. This predation pressure can prevent the overpopulation of certain species, which might otherwise lead to imbalances and the depletion of critical resources. Pikeminnow also serve as food for larger predators, including birds of prey and other fish species, especially in the summer months when salmon aren’t present. As well, they are a traditional food source for Native peoples in the Central Valley, Clear Lake, and Russian River.

ARE PIKEMINNOW A PROBLEM?

While Sacramento pikeminnow are native to many California waterways, their introduction to the Eel River represents a significant ecological challenge as does their interaction with fisheries recovery efforts in rivers where they are native. As generalist predators that thrive in warm water environments, water infrastructure like reservoirs and diversion dams can create novel habitats that benefit pikeminnow and can lead to predator hot spots even in places where they are native.

“For fly anglers, embracing the opportunity to fish for pikeminnow can contribute to a deeper understanding of the intricate connections that sustain California’s rivers.”

It’s important to distinguish between places where pikeminnow are introduced and invasive—like in the Eel River and tributaries to Morro Bay —and where they are native. Where pikeminnow are native, water management actions that simplify river systems, create pinch points, and increase the amount of warm water habitat available during California’s natural summer dry season can benefit pikeminnow and other warm water species, hampering salmon recovery efforts. This has led to eradication efforts in places like the Sacramento River at the Red Bluff Diversion Dam where large pikeminnow congregate, and somewhat famously on the Columbia River where the closely related Northern pikeminnow prey on salmon, especially naive hatchery fish. On the Columbia, a successful bounty program pays anglers to catch and remove native pikeminnow helping offset the impacts of dams and increase the survival of hatchery salmon. Similar programs have been discussed in California, but none are currently active. Overall, the question of how to manage native predators is a difficult one, especially given the cultural and economic importance of declining salmon populations.

On the Eel River, management actions are clearer. The Eel was historically home to some of the largest populations of salmon and steelhead in the state. Pikeminnow were introduced into Lake Pillsbury reservoir in the upper Eel River in the 1970s or 80s and have since spread throughout the basin. Dr. Gabe Rossi, a CalTrout-UC Berkeley coastal rivers ecologist, notes, “Pikeminnow aren’t the cause of salmon decline in the Eel River, but they are an impediment to salmon recovery, and recovery of other native fish.” This new predation pressure exacerbates the already significant challenges facing salmon and steelhead.

Marisa McGrew, a fisheries and natural resources specialist for the Wiyot tribe, explains, “They’ve coexisted in many places, but in the Eel they have made it harder for native fish to rebound from historic impacts.” The introduction of pikeminnow, though unintentional, has added another layer of complexity to the recovery of Eel River salmon.

EFFORTS TO ERADICATE PIKEMINNOW FROM THE EEL RIVER

The Wiyot tribe has been actively involved with pikeminnow management since 2018, implementing both monitoring and suppression efforts. Historically, pikeminnow have been blamed for various ecological issues without a strong understanding of their biology and behavior. To rectify this, the tribe has partnered with Stillwater Sciences, UC Berkeley, and the nonprofit California Trout to better understand pikeminnow and their impact on the ecosystem. This collaboration began with a Tribal Wildlife Grant focused on lamprey recovery, a species culturally significant to the Wiyot people. During this monitoring, researchers observed pikeminnow preying on ammocoetes, the larval stage of lamprey.

The Wiyot tribe has employed various techniques to monitor and suppress pikeminnow, including snorkeling, seining, boat electrofishing, hook and line, gill nets, and spears. Alex Juan, a graduate student at CalPoly Humboldt, has contributed valuable research on the biology of pikeminnow in the Eel River, noting their sexual dimorphism, with females growing much larger than males. These efforts and others have helped the Wiyot tribe’s Natural Resources Department become experts in tracking, monitoring, and suppressing pikeminnow, contributing significantly to the broader understanding and management of the species.

CalTrout’s weir on the South Fork Eel River. Photo by Mike Wier, courtesy of CalTrout

In 2023, California Trout received funding to experiment with a weir on the South Fork Eel River. A weir is an ancient technology that is essentially a fence across the river that restricts fish movement. It allows for capturing and removing pikeminnow while letting native fish pass up and downstream. This approach aims to reduce pikeminnow predation on juvenile salmon and steelhead by removing the larger piscivorous and spawning female pikeminnow. Acoustic telemetry and AI technology are used to track fish movements and gather vital data, enhancing understanding and management of the ecosystem.

The weir was successful in its first year of operation. However, Dr. Rossi emphasizes, “Complete removal is near impossible, and the methods we would need to take to do so would cause ecological risk.” Chemical treatments, such as rotenone, have been employed in other rivers to reduce invasive fish populations, but their use is undesirable due to potential impacts on non-target species and the broader ecosystem.

Snorkle surveys check for pikeminnow above the weir. Photo by Mike Wier, courtesy of CalTrout

McGrew highlights the importance of treating pikeminnow with respect despite their invasive status. “It’s not the fault of the fish that they’re in the Eel River, they were placed here by people,” she says, underscoring the need for an informed approach to management. As part of the Wiyot tribe’s efforts to remove pikeminnow from the Eel River, they have tried to make use of the culled fish, providing them to crab fishers for use as bait and to tribes around Clear Lake where pikeminnow is a traditional food source. In a sad twist of fate, pikeminnow, once abundant in Clear Lake where they are native, have been driven to near extinction partly due to the introduction of non-native bass.

FLY FISHING FOR PIKEMINNOW: A UNIQUE CHALLENGE

Growing up near the Russian River, Trevor Evans got his start fishing for steelhead, but like many anglers, he started seeking out summer fishing. “I would catch 12- to 16-inch pikeminnow frequently while fishing for bass, but once I realized how big they get, I started really targeting them.” Despite many anglers complaining about catching pikeminnow while targeting steelhead or bass, targeting them can be a fun and new challenge. These fish are known for their strength and tenacity, making them formidable opponents on the fly rod. Their aggressive feeding behavior means they are often willing to strike a variety of fly patterns, from streamers and nymphs to topwater flies, depending on the time of day and conditions.

Zac Reinstein, a seasoned fly angler and fisheries biologist, shares that pikeminnow “Can hit hard or subtle, on top or bottom. They’re very strong and make long runs. They use their weight and current to their advantage.” He adds, “Big ones are not easy to catch even though you can often sight fish for them. Fish don’t get to be that big without being smart.”

The Sacramento pikeminnow deserves reevaluation in the fly-fishing community. Far from being a “junk fish,” pikeminnow offer a challenging angling experience while playing a vital role in their native ecosystems. Everyone I spoke with in writing this piece shared their appreciation for the species, many noting how impressive they are to watch hunt or take a fly. While they are an important part of their native ecosystems, sport anglers can take solace in the fact that they are relatively abundant and tolerant of warmer water temperatures which reduces the impact an angler has on them.

In the Eel River, the story of pikeminnow is more complex, highlighting the challenges of managing invasive species and protecting native fish populations. Efforts to control pikeminnow in this context are critical to restoring and preserving the river’s iconic salmon and steelhead.

For fly anglers, embracing the opportunity to fish for pikeminnow can contribute to a deeper understanding of the intricate connections that sustain California’s rivers. To treat them with disrespect is unwarranted. These aggressive predators that manage to grow large in freshwater ecosystems are worth seeking out.


FISHING FOR SACRAMENTO PIKEMINNOW

Not beauties, but fun to catch. Photo by Zac Reinstein

Looking to catch Sacramento pikeminnow? Target them in the South Fork and Mainstem Eel River, where they are invasive, and in the Sacramento and Russian River systems. For best results, fish in slower-moving waters and deep pools. Use a variety of fly patterns—streamers, nymphs, and even topwater flies. Pikeminnow are strong fighters and not particularly leader shy so a heavier 1X or 2X tippet is recommended. Sight fishing is particularly effective so keep an eye out for these impressive fish. Remember, larger pikeminnow are elusive and require skill and patience to catch. Don’t be afraid to fish big streamers and work the entire water column. The largest fish tend to be most active in the mornings and evenings. Happy fishing!

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