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An icon, and perhaps casualty, of California’s contentious water policies. US Fish & Wildlife Service, CC BY-SA

Swimming upstream: plight of Delta smelt exposes flaws of the Endangered Species Act

In July, the California Department of Fish and Wildlife made a startling announcement. Its most recent survey of the California Bay Delta netted only a handful of Delta smelt, an endangered fish species.

The number was so low that the smelt’s “relative abundance,” a statistical measure of how common a species is compared with others in the same area, rounded off to zero. This led University of California at Davis biologist Peter Moyle, who has studied the Bay Delta’s fisheries since the 1970s, to conclude that the smelt is “on its last legs right now. We’ll be lucky if it survives the coming year.”

The smelt’s decline has come to symbolize both California’s history of dysfunctional water politics and the Bay Delta’s slow-motion ecological collapse. The fish’s likely imminent extinction in the wild also raises a key question in American environmental policy: how well has the Endangered Species Act (ESA) of 1973 – the strongest conservation law ever adopted by any nation – protected this country’s imperiled plants and animals?

The California Bay Delta acts as a water storage and distribution point in the state’s vast water infrastructure., CC BY

The ESA has two main goals: to prevent the extinction of endangered species and to recover vulnerable plants and animals to the point where they can be removed from the endangered species list. It seeks to achieve these goals by ending overharvesting, conserving habitat, mitigating diseases, controlling exotic pests and, in extreme cases, breeding plants and animals in captivity. Since 1973, the federal government has listed around 1,500 species as protected under the ESA. Of these, just 10 (0.6%) have gone extinct, but only 30 (2%) have recovered. More than 97% remain on the list.

There is a lot these statistics don’t tell us, including the amount of resources dedicated to recovery programs and whether listed species are declining or rebounding over time. What they do show is that although the ESA has done a remarkable job preventing extinctions, so far it has resulted in too few recoveries. To understand why, let’s look at both sides of the ledger, beginning with the departed.

Emergency room

All 10 of the species declared extinct since 1973 were already in big trouble by the time the ESA became law. Several lived in just one or two isolated areas, and most had very specific resource requirements. Some had lost their entire wild habitats or survived only in captivity. At least five may have disappeared even before being listed. During the past decade, the federal government has reclassified only one listed species, the Caribbean monk seal, as extinct. The truth, however, is that this charismatic marine mammal probably vanished more than half a century earlier.

This does not mean that extinction is a thing of the past. Thousands of species around the world remain in grave danger. The International Union for the Conservation of Nature lists 326 species in the United States alone as critically endangered, meaning that they have an “extremely high risk of extinction in the wild.” But although many species remain on the edge, surprisingly few in this country have been confirmed extinct.

Now let’s consider the recoveries. Of the 30 recoveries to date, almost all have involved species, such as the American alligator and brown pelican, that declined due to a single, relatively straightforward problem like disease, pollution, or overharvest. Remove the limiting factor and the species has a good chance of bouncing back.

By contrast, recoveries have proven much more elusive for the vast majority of listed species, like the northern spotted owl and Mojave desert tortoise, whose populations have declined due to multiple, complex habitat-related problems. For many such species, the ESA seems more like a permanent emergency room than the revolving door its authors intended.

Disrupted habitat

Viewed in this broader context, the Delta smelt is both typical and unusual.

The smelt is typical, because, like many other endangered species, it is picky about its habitat: it lives only in the Bay Delta’s brackish waters, where it eats plankton and drifts with the tides. It also has the common misfortune of dwelling in a severely altered and degraded ecosystem.

The Bay Delta, which once served as the confluence of California’s two great rivers, the Sacramento and San Joaquin, now acts mainly as a storage, redistribution, and flood control apparatus for the state’s vast water infrastructure. It is a disorienting and often bizarre region of elevated waterways and sunken farms, where many streams flow uphill (toward pumping stations) and exotic species comprise more than 95% of the biomass. Given the deplorable condition of its habitat, it is no surprise that the smelt is in such bad shape.

The smelt is unusual because, unlike most endangered species, it appears to be going extinct in the wild. If its population drops to zero and the federal government removes it from the endangered species list, it will be the first official extinction in the United States since 2008. Indeed, it may be the first time any American species that had a viable population at the time of its listing goes extinct despite the benefit of a mature and fully functional ESA.

Fortunately, we will probably not have to face this grim scenario. Smelt are tricky to maintain in captivity, but two hatchery populations, one at UC Davis and one at Shasta Dam, are well-established. Endangered species have vanished from the wild before only to return to their native haunts with the help of captive breeding and reintroduction programs. The problem is that reintroduction requires suitable habitat.

An ambitious new habitat conservation plan is in the works for the Bay Delta. Such plans hold great promise. Yet, in other areas they have contributed little to the recovery of listed species. Even if the Bay Delta plan moves forward, it will not resolve the multiple, complex forces behind the smelt’s decline any time soon.

Road to recovery?

The Delta smelt’s brush with oblivion reminds us that the loss of unique plants and animals remains possible, even when such species have the protection of the world’s most powerful conservation law. A review of the ESA’s record, however, suggests that although such losses are terrible to contemplate, the more pressing challenge in the United States is not preventing extinctions, but rather achieving recoveries.

Congress has done little to improve the ESA since its last major amendments to the Act in 1982, but a few key changes could make recovery efforts more efficient and effective. To help more endangered species achieve robust and sustainable populations, policymakers should support:

  • more proactive projects that seek to prevent species from becoming endangered in the first place

  • stronger incentives for the protection and restoration of privately owned lands and waters where many endangered species live

  • more flexibility to engage in “adaptive management” efforts designed to produce new knowledge that improves conservation

  • better links between recovery programs and related initiatives, such as habitat conservation plans

  • the allocation of more resources for recovery efforts, at the state and federal levels.

The problems facing most endangered species are numerous and complex. But after four decades of rearguard action, American conservation is very much in need of more success stories.

Moving from a period of rescue to an age of recovery for America’s endangered species will require all of the tools conservationists have, from captive breeding to habitat restoration.

A few modest changes to the ESA could greatly improve this landmark statute by better integrating these diverse approaches, incorporating new ideas and refocusing conservation efforts on the law’s recovery goals. One day, they might even bring back the Delta smelt.

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