Skip to main content

How a Tiny Fish Made a Huge Splash in California’s Water Debate

Should the needs of a threatened species be prioritized over the demands of agricultural and urban interests?

By Andrew Lakoff


Delta smelt. (Photo: United States Fish & Wildlife Service)

In the final week of his ill-fated presidential campaign, Senator Ted Cruz traveled to California to make an appeal to conservative voters in the agricultural Central Valley. His pitch centered on the delta smelt, a small, endangered fish that the region’s farmers have blamed for cuts in their supply of water from Northern California. Cruz excoriated “out of control environmental policies” that required the state’s water project operators to decrease pumping rates in order to protect the smelt during its migration and spawning season. These policies, he charged, had led to “1.4 trillion gallons of fresh water being dumped into the Pacific Ocean because of a three-inch bait fish.”

The accusation was a caricature of a complex debate — not least because the fresh water was essential to the threatened ecosystem of the San Francisco Bay Delta. But Cruz’s comments pointed to a long-running political conflict in the state over the proper uses of water. As California’s population continues to grow and its available water decreases, what values should govern the allocation of its limited supplies? And to what extent should the needs of threatened species such as the smelt be prioritized over the demands of agricultural and urban interests to the South?

For these various critics, the problem was that the life of a mundane fish was being prioritized over the livelihoods of humans.

Early in the year, a series of winter storms brought long awaited rain and snow to Northern California. This should have been good news for the utilities that provide water to the arid central and southern regions of the state. California’s water infrastructure is designed to capture flows from northern watersheds and transport them to a network of reservoirs, to be gradually released to the farms and urban agglomerations to the south. By March, however, it seemed that the storms’ bounty would not be widely shared. Due to pumping restrictions linked to enforcement of the Endangered Species Act, a significant amount of the fresh water inflows had been allowed to pass through the Bay-Delta estuary into the San Francisco Bay.

Water contractors and politicians seethed with frustration. “Days of high flows were squandered,” protested Senator Diane Feinstein in a press release decrying the pumping restrictions. The Metropolitan Water District, which supplies millions of Southern California consumers, argued that the restrictions had cost the district nearly a half million acre-feet of storage, enough to supply the needs of 3.6 million people for a year. “That water is now gone forever,” complained a spokesman for the Westlands Water District. In these critics’ view, water that was not pumped for urban or agricultural use — and instead wound up in the ocean — was water wasted. The powerful water utilities saw no value in attending to the needs of a small, inedible fish.

The delta smelt was officially listed as threatened under the Endangered Species Act in 1993.

The movement to list the delta smelt as threatened was due neither to its economic value to fisherman nor to its symbolic value as a unique species. Rather, the smelt was a proxy in a larger struggle to ensure the viability of the Delta ecosystem, a critical habitat for dozens of native fish and birds. The Endangered Species Act, though it could focus on only a single species, was the strongest available regulatory tool to wield against economic arguments for fresh water diversion.

But the view of fresh water flows as a natural resource to be exploited for human purposes has long been at the heart of the state’s water circulation system. In 1963, President John F. Kennedy voiced such support in a speech dedicating a portion of the federally funded Central Valley Project: “For too long this water ran unused to the sea.” Rather than waste this “surplus water,” Kennedy declared, it would be put to human use, “to irrigate crops on the fertile plains of the Sacramento Valley and supply water also for municipal and industrial use to the south.” After another major water delivery system was completed in the early 1970s, fresh water diversions from the Delta reached an average of six million acre-feet per year.

But in the years that followed, it became clear that the flows from northern rivers, as they made their way out to sea through the Delta, had, in fact, served important other needs. As an increasing percentage of the Delta’s inflows were delivered south, the estuary was radically transformed through saltwater intrusion, the proliferation of invasive species, and the rapid decline of native fish populations.

In the decade after the smelt was declared threatened, little progress was made in balancing between urban and agricultural demands for water, on the one hand, and the needs of the ecosystem on the other. The decline of fish populations continued alongside the growth of Central Valley agriculture and Southern California cities. But in 2007, a major court victory for the smelt’s advocates changed the dynamic of government regulation of water deliveries from the Delta.

The smelt was a proxy in a larger struggle to ensure the viability of the Delta ecosystem.

The so-called Wanger decision, named after a federal circuit court judge in Fresno, ruled that the water projects’ pumping activities posed an unacceptable risk to the survival of the smelt. The judge ordered the Fish and Wildlife Service to generate a revised “biological opinion” — the document that regulates federal agency action under the Endangered Species Act — that would effectively monitor and protect the smelt population.

The resulting opinion required federal wildlife biologists to pay careful attention to the relation between the vulnerable smelt and the water projects’ voracious pumps — gigantic machines that have the strength to reverse the course of two tributaries that feed the Delta. The Wanger decision set a threshold on the maximum number of smelt that could be “entrained” in the projects’ pumps; and it required water project operators to track the physical location of the fish, reducing pumping rates at times when the fish were at risk of being salvaged in high numbers.

Over the next several years, water contractors blamed these regulations for cutbacks in the amount of water shipped to the south. The uncharismatic smelt became an easy target for Central Valley politicians in their attacks against the Obama administration’s environmental protections. At the same time, the protection efforts failed to stem the decline of the smelt population. By 2015, the species was on the verge of extinction, its presence measured at the lowest rates in recorded history.

For this reason, in early 2016, federal wildlife authorities were highly attuned to the needs of the smelt as they entered their most vulnerable period, the months from January to March when they migrate and spawn. Unfortunately for the fish, this was the very moment when massive water flows were entering into the system from winter storms, and water contractors to the south hoped to re-fill their reservoirs with large volumes of imported water.


The Delta viewed from above Sherman Island, with the Sacramento River above and San Joaquin River below. (Photo: Wikimedia Commons)

During this sensitive period, a working group representing the relevant government agencies met regularly to assess the risk posed to the fish by the water projects’ pumps, and to propose limits on the rate of reverse flow caused by pumping. Based on the group’s recommendations, project operators limited pumping speeds to rates that reversed the course of the rivers at only one-quarter to one-third of their maximum rate. This meant, in turn, that much less of the late winter rainfall than the water utilities hoped went to replenish the receding reservoirs of Central and Southern California.

In a public letter to President Barack Obama, Feinstein argued that the water system was bound by “a dogmatic adherence to rigid operating criteria that continues to handcuff our ability to rebuild our reserves.” She recommended that project operators be given more flexibility to increase pumping rates in order to fill reservoirs. Meanwhile, Republican congressmen from the Central Valley demanded that pumping levels be increased “over and above” the maximum rate allowed by the Endangered Species Act. In late May, Donald Trump weighed in on the debate during a campaign swing to the state. Alluding to the protection of “a certain kind of three-inch fish,” he echoed the water utilities’ criticism of Delta pumping restrictions: “It is so ridiculous where they’re taking the water and shoving it out to sea.”

For these various critics, the problem was that the life of a mundane fish was being prioritized over the livelihoods of humans. But from the perspective of its defenders, the smelt’s significance was not only as a species whose right to existence was protected by the Endangered Species Act. Rather, for ecological scientists and environmental advocates, the smelt population was an indicator of the health of the Delta as a whole. The smelt was just one of numerous native fish whose numbers were collapsing, signaling a crisis of the entire ecosystem.

If the wildlife service’s biologists were speaking for the fish, it might be said that the fish were speaking for something else: a critical habitat, a setting vital to human and non-human life, whose declining condition could only be ascertained by surveys of its native fish.