California runs hot and cold on striped bass

Remember, there’s a reason it’s called “fishing” instead of “catching.” When you tell people you’re heading to the river in hopes of making the acquaintance of a striped bass, you’ll receive this warning from approximately half of them. With this in mind, you softly crunch your way down to the water over a waxen carpet of ice plants to your fishing spot. You take care finding the perfect rock to stand on while you extend your thorny greeting to any interested fish. You might wait there all morning, watching the light reflect off the water and cast twinkling patterns on the underside of a bridge. But as the hours flow past, you settle into a state of near-meditative waiting. Nothing stirs, nothing bites. But isn’t this lovely? You might even start to convince yourself: hey, it is all about the fishing! Catching is for chumps.

All that leaves your mind when a striped bass finally bites. These fish, affectionately called stripers, put up an outsized fight for a fish of their size. Your striper — the one you caught, thank you very much — provides the exhilarating scuffle you’d begun to believe you didn’t want. Your quarry feistily thrashes its powerful tail back and forth, creating arcs of splashing water that mirror the bow of your fishing rod.  In a minute, you’ll have to deal with the fact that you have a living, flopping creature snagged on a hook. But for now, you have to throw your whole heart, soul and elbow strength into subduing that creature in a battle of wills.

Anglers might feed you the “fishing not catching” line, but many are in fact in it for the thrill of the catch. If they weren’t, the recreational striped bass fishery wouldn’t be quite as popular as it is. Recreational anglers cherish stripers for the fight they put up when caught and for their sweet, flaky meat.

But not everyone is so fond of the striped bass. Stripers eat chinook salmon, another well-loved California fishery that’s dwindling due to population loss. And unlike striped bass, chinook salmon are native to the area.

After a century of balanced coexistence between stripers and native fish, some Californians say that striped bass have begun to threaten native species like chinook salmon. Still, policymakers and fisheries must figure out how to protect native fish living alongside stripers, which have found their own place in California’s river ecosystems and in the hearts of its sports fishers. Some claim that an unchecked striped bass population could devastate native fishes. Others believe these anti-striper sentiments are couched in greed rather than reality — a diversion from the damming, pumping and irrigation practices that truly threaten native salmon. “Everybody who works with them feels one way or the other,” says Cyril Michel, a fisheries ecologist at the National Oceanic and Atmospheric Administration. “Nobody’s neutral on striped bass.”

A tale of stripes and strife

The history of striped bass in California is deeply entangled with the history of white settlers who moved here to seek their fortunes. “We found gold in 1848, ” says Matt Petersen,  a fisheries biologist at a private consulting company called FISHBIO. “And it went downhill from there for fish.” Mining diverted streams to sluice gold from the hills, which polluted local waters with mercury and other contaminants. And suddenly, the San Francisco Bay Area was bustling with far more people than before—people who needed to eat. Over the next few decades, farmers built dams and levees, diverting rivers to irrigate food crops for the newcomers. The state also stocked California waterways with new types of fish to eat.

Before 1879, there were no striped bass in California. That year, the California Department of Fish and Wildlife, then the Department of Fish and Game, loaded 132 stripers into milk cartons and carted them via train from New Jersey to the Carquinez Strait, which connects the Sacramento-San Joaquin Delta to the San Francisco Bay. As Fish and Wildlife had hoped, the striped bass were tasty and delightful to fish for sport. So much so that Fish and Wildlife introduced 300 more stripers into the nearby Suisun Bay in 1882. That’s all it took: striped bass were in California to stay. And like the waters of the Delta, local opinions have run hot and cold on striped bass since then.

For over a century, Californians couldn’t get enough of stripers. Anglers found striped bass so fishable that the striper population couldn’t keep up. The state banned commercial fishing of striped bass in 1935 to ensure a big enough striper population for the high-demand recreational fishery. Fish and Wildlife estimates that the San Francisco Bay estuary held around 3 million stripers in the early 1960s, but that population dwindled to around 600,000 by 1990. Some analyses attribute this to the growth of power plants along the river in and after the 1970s, which interfere with the migrations of juvenile stripers and other fish as they move towards the sea. At anglers’ request, the California legislature established a Striped Bass Management Program in 1981 to address that population decline. Private- and state-run hatcheries supplemented the stock in the late twentieth century, adding up to 300,000 stripers to California’s rivers each year.

But then the tide of political support began to shift away from striped bass. In 1992, Fish and Wildlife stopped supplementary stocking over concerns about the effect on chinook salmon,  which were experiencing a major population dive. But perhaps in a bid to protect revenues from fishing licenses, which generated around $45 million in. revenue in 1996 (equivalent to over $81 million in 2022, accounting for inflation), Fish and Wildlife reaffirmed its goal to boost the striper population to 3 million through “any appropriate means.” At the time, anglers were required to purchase a specific striped bass stamp to legally use the fishery, which generated over $1.3 million per year on average (equivalent to about $2.3 million in 2022) throughout the 1990s—meaning almost 400,000 anglers paid the additional $3.50 to fish for stripers each year.

In 2003, the state introduced legislation to end the Striped Bass Management Plan it had implemented two decades earlier and the stamp program that supported it. “Striped bass populations have been steadily increasing,” the Assembly Floor Analysis, a unit of the Chief Clerk’s office that provides non-partisan assessments of certain California legislation. “In fact, they have reached a point where predatory striped bass, an introduced species, are becoming a problem in recovering certain native species of fish.” The state legislature voted to amend the Fish and Game code and allow the striped bass stamp (and the funding it brought for maintaining high striper populations) to lapse.

A proxy battle in the Delta

In 2008, a non-profit group of “water users” called the Coalition for a Sustainable Delta teamed up with several water utility companies from Southern California to sue Fish and Wildlife in the United States Court for the Ninth Circuit for mismanaging striped bass. The suit alleged that Fish and Wildlife’s striper policies “cause a striped bass population that is higher than it otherwise would be in nature.” This statement certainly holds water, given that the stripers are not native to the area.

But then some feel the suit’s claims got a little fishy. The plaintiffs went on to suggest that those policies violated the national Endangered Species Act. By seeking to increase the numbers of striped bass in California, the Coalition claimed, Fish and Wildlife jeopardized endangered native species like chinook salmon and California steelhead in the Delta and the Central Valley.

The stripers, many felt, were being asked to atone for the sins of water agencies and irrigation utilities.

The stripers, many felt, were being asked to atone for the sins of water agencies and irrigation utilities. In a news article, fisheries scientist Peter Moyle called striped bass a “scapefish.” “Water management has often been blamed for the decline of salmon populations,” Michel says. “A lot of water-focused groups have tried to redirect some of that ire towards striped bass.” But this doesn’t mean the Coalition’s arguments were completely unjustified, he notes.

“Before we started messing with the river systems and damming and diverting, striped bass and salmon — well, I wouldn’t say they lived together harmoniously, because striped bass were certainly still eating salmon back then,” says Michel. The native fish were able to maintain healthy populations, and the bass were happy to snack on them. The balance was only disturbed towards the end of the twentieth century, when humans began to bend the water to their will to irrigate crops and generate electricity at pumping plants. Much of the salmon’s lost range isn’t even in areas with dense striper sightings, according data from the United States Geological Survey and the University of California Davis’s PISCES Project.

But the scapefishing routine seemed to work. In 2011, Fish and Wildlife settled the suit under the conditions that they must develop a new regulatory proposal including an “adaptive management plan” to determine the effects of any changes to striped bass populations. Fish and Wildlife proposed regulatory changes that would allow anglers to take striped bass of smaller size and in larger quantities. The new regulations aimed to reduce the striped bass population, but some Californians were skeptical about their potential to protect native fish. The Golden Gate Salmon Association submitted an alternate proposal focused on detrimental water pumping rather than striped bass predation. The California Fish and Game Commission rejected the plan during a meeting where they heard fierce opposition from anglers and conservation groups. ​

As for the stripers’ public image, the damage was already done. “When it comes to striped bass in California, people who know just a little bit about the issue, are like, ‘Okay, striped bass are bad. We should get rid of them, and then we’ll have more native fishes,’” says Will Ware, a fisheries biologist at FISHBIO. “But that’s not how it works. Fish are complex.”

Fans and advocates of the recreational fishery have come to the stripers’ defense, asserting that water diversion practices hurt striped bass in addition to native fish. For some, the striped bass fishery feels like an underdog due to the socioeconomic differences between anglers who fish for stripers versus those who fish for salmon. “For striped bass fishing, you can go pretty much anywhere in the Delta or along the Sacramento River,” says Dylan Stompe, a graduate student at the University of California, Davis, and former environmental scientist with Fish and Wildlife. “Salmon, there’s only a couple spots where you can effectively shore fish along the rivers. Most people fishing for salmon are doing it in a boat, so it limits the number of people who can do it.”

After over a century with its stripers, California still doesn’t quite know what to do with them. In 2020, Fish and Wildlife amended their striped bass policy to reaffirm their older goal of promoting a robust, self-sustaining recreational fishery while striving to support threatened and endangered species. The current policy doesn’t specify any means to that end. In the meantime, Fish and Wildlife and other entities have been working to understand the balance between stripers and native fish in the Delta.

“If you were to somehow magically press a button and return the Central Valley to its early-1900s state, the striped bass could still be here, and we’d still have healthy salmon populations,” Michel says. “But that’s not a realistic goal.”

Instead, policymakers must search for a way forward. And that path requires further research to understand how striped bass operate in California and how often those operations involve chowing down on native fish.

Understanding the scapefish

Just like its occupant, Will Ware’s office at FISHBIO is fastidiously organized and all about California fish. Stylized art prints of fish hang above an aquarium full of their living, burbling counterparts. Fishing equipment leans neatly against a bookcase full of fish-themed books. In the middle sits a man who spends countless hours reading scientific studies and analyzing data about striped bass. “It’s a love-hate relationship,” Ware says of the data analysis. “Sometimes I like it. Sometimes it doesn’t like me back.” Nonetheless, he lets the work surround him.

Ware is a master’s student in the University of California, Santa Cruz’s Coastal Science and Policy program. For his capstone project, he’s working as a fisheries biologist at FISHBIO. He’s endeavoring to measure where and when striped bass of different sizes reside in the Stanislaus River, which flows into the San Joaquin River and on into the San Francisco Bay.

Ware and Petersen both work on sub-projects of FISHBIO’s Stanislaus Native Fish Plan, which studies factors that imperil chinook salmon and other native fish on the Stanislaus River. Understanding how striped bass interact with endangered native fish is a cornerstone of the project. “We’ll have four complete seasons of this data,” Petersen says. Most fish projects are more like one-off experiments, he notes, so he’s excited to have so much data on bass behavior.

The project doesn’t just focus on striped bass, but they’re of particular interest. “Other non-native predators like black bass are a big concern,” Ware says. “But typically, they stay in the same areas of a river. Sometimes they like a specific fallen tree, and that’s their spot.” Not so for striped bass, who live their lives with a bit more wanderlust. Stripers require plenty of prey to fuel this energetic lifestyle, which is why researchers have such a close eye on their salmon consumption.

One of the most promising principles for protecting California’s native fish populations is to minimize their chances of meeting a predator. Each spring, young salmon migrate to the ocean, which boasts enough crustaceans, insects and other tasty treats to power them through their adolescent growth spurts. But to reach the relative safety of the sea, they must swim a gauntlet of predators whose appetites grow more voracious as the springtime temperatures rise.  “There’s kind of a ticking time bomb in the Delta,” Michel says.

FISHBIO researchers collecting data about striped bass in the Stanislaus noticed that they were capturing different-sized stripers at different points during the sampling season, which stretches through spring and summer. Larger striped bass with larger appetites to match were coming into the Stanislaus earlier than smaller striped bass. Ware wants to explore this timing to determine when salmon smolts are most at risk of becoming a striper’s meal. This could help hatcheries know when to release salmon smolts or let Fish and Wildlife set up anti-predator measures, like gates that bar large fish from certain areas of the river, for the most crucial time periods.

Hungry stripers don’t just chow down on salmon smolts, though.  “If you look at all the things any individual striped bass would eat across a whole year, salmon probably constitute a fraction of a percent of that fish’s diet,” Michel says. Stompe wanted to know what exactly striped bass eat and how their diet compares to that of the pikeminnow, a native predator fish. He and a team of researchers went fishing (and catching) along the Sacramento River. When they caught a striper or pikeminnow, they pumped its little fish stomach and analyzed its recent meals. After assessing the stomach contents of 47 striped bass, they found that stripers mostly eat insects, with chinook salmon a far second.

What’s more, the researchers found that striped bass have nearly identical diets to native pikeminnow, and the two species have expanded into many of the same areas over the past century. “They’re probably functioning more as a native predator than an introduced species that’s devastating the system,” Stompe says of striped bass. If the stripers were suddenly gone, Stompe says, it’s likely that more pikeminnow or some other predator fish would occupy that niche instead. And more pikeminnows might not be a crowd-pleasing solution — some anglers hate the bony, listless pikeminnow so much that when they catch one, they toss it up on the shore rather than return it to the water or keep it to eat, Stompe says.

But predator fish aren’t the only threat to chinook salmon smolts. Like stripers, young salmon face dams, irrigation pumps and other manmade hurdles as they journey from their freshwater spawning grounds to the ocean. Which raises the question: To what extent do predator fish effect salmon survival? In 2014 and 2015, Michel and a team of researchers removed all the predator fish they could from three stretches of the San Joaquin River, each 1 kilometer long. They sailed three boats up the river in a V-shaped formation, sending electrical currents through the water to stun fish. As the dazed river denizens floated to the top, Michel and his team scooped up any predator fish they saw—about 3,000 fish in total, including mostly stripers, largemouth bass and catfish. The researchers hauled all those predators to another location far downstream.

The research team tethered chinook salmon smolt to buoys and counted how many predators took the bait in the weeks before and after the predators were relocated. They also measured the survival of tagged salmon in areas where the predators had been removed and compared it to areas where predators had been added or areas where the predators had been left undisturbed. Michel and his team reported that predator removal made no significant difference for chinook survival. Nor did adding more predators.

“There are probably ways where we could really damage the striped bass population if there were no holds barred,” Michel says. Some states hold derbies where anglers compete to remove as many members of an unwanted predator species as possible. Oregon and Washington offer cash rewards for pikeminnow. But Michel’s results indicate that removing stripers won’t help salmon, which raises a new question: How can we protect native fish if removing their non-native predators doesn’t help?

Fishing for solutions

In the wake of the striped bass scapefishing, researchers have identified tactics that could slow or reverse the decline of native fish populations. Artificial lights at night attract predators and prey alike, creating hot zones where they interact. Eliminating artificial night lighting near rivers that are home to salmon could protect them by creating fewer of these hot zones, and it’s much easier than scooping every striped bass out of each river.

Non-native vegetation that grows along riverbanks also leads to more interactions between chinook salmon and their predators. These plants create a sanctuary for predator fish to lurk in until an unsuspecting salmon comes their way. Better salmon conservation policies may dovetail with better management of these plants, Michel says.

And many proposed methods to help salmon survival don’t have anything to do with striped bass or other predators. Instead, researchers and policymakers are looking to strategies that give salmon the best chance of navigating less combative aspects of their lives. These solutions include releasing salmon from hatcheries when water conditions are optimal to ensure they’re starting their river journeys with a fighting chance.

Anglers admire striped bass for their strength of will, their ability to hurl themselves around and achieve the fight of a much larger fish. But human attempts to flail against nature’s limitations have created a crisis in the Delta. Striped bass are in California’s waters to stay, and policymakers may have to seek solutions closer to home, whether they’re addressing light pollution, hatchery practices or water policies that endanger native fish.

That may not happen any time soon. Policies to deplete stripers raise opposition from angling associations, and policies that might allow striped bass populations to grow could incur more lawsuits from water management companies. Fish and Wildlife’s prerogative is to protect natural resources, like salmon and other fishes. But most of the funds they use to do that come from recreational fishing licenses. “It’s a very messy web,” Stompe says. “And right now the Department [of Fish and Wildlife] is in a holding pattern.”

How Fish and Wildlife navigates this issue will determine how the joys of fishing (and catching, if you’re lucky) will endure in California.

© 2022 Graycen Wheeler / UC Santa Cruz Science Communication Program