Extinction in the wild looms for two California fish (commentary)

Over at the California Water Blog, UC Davis fish biologists Peter Moyle and Jason Baumsteiger observe that two species of California fish — one small and the other big — appear to be on the verge of imminent extinction in the wild. The delta smelt (Hypomesus transpacificus) and the winter-run Chinook or king salmon (Oncorhynchus tshawytscha) have long been in dire straits.

The plight of these two hapless species symbolizes how biodiversity and wild nature in California are being pummeled by a human population now numbering nearly 40 million. In stark contrast, only six tiny smelts, the lowest number ever recorded, were counted in a survey by state fishery biologists in 2015; in previous years, up to several hundred had been netted.

The human population in California, in both its rural and urban manifestations, is exerting an ever-greater load on the environment — in this case, via ever-increasing competition for the precious and all-too-limited resource, water. At the moment, California is bathing in water after the wettest winter on record, but we all know that won’t last. The state has always been plagued by multi-year droughts, but climate modelers predict that it may be punished by a “terrifying” scenario of longer-lasting “megadroughts” in the future.

The delta smelt is a three-to-four-inch long, silvery-blue fish that has long been at the center of California’s contentious water wars. It lives only in the San Francisco Bay and the Sacramento-San Joaquin Delta, and its numbers have been declining for decades as enormous quantities of freshwater are diverted through the state’s vast network of aqueducts and canals.

It used to be that the force of Sacramento River and San Joaquin River flows pushed back against saltwater from San Francisco Bay (and smaller connected bays such as San Pablo, Suisun, Grizzly, and Honker), preventing the salty wedge from protruding too far upstream into the fresher water (less brackish) delta. The delta smelt foraged in the brackish bay and spawned in the freshwater delta.

The freshwater river flow also replenished Chinook salmon spawning grounds and freshened habitats (reducing salinity) in San Francisco Bay for waterfowl, Dungeness crab, and countless other aquatic flora and fauna in an immense system of sloughs, mudflats, and marshes.

Now, however, most of that water is diverted to California’s thirsty farms and clamoring, growing cities. And the two fish species are dying out as a result. If they disappear altogether from the wild, they will join approximately 57 other fish taxa declared extinct in North America since about 1900. Seven fish species in California have gone extinct.

However, captive populations of both the salmon and the smelt are being maintained (and carefully protected against inbreeding) to guard against their complete obliteration from the universe. Perhaps someday, when conditions in the wild have improved, these survivors might serve as a “seed source” to re-establish wild populations, although this is a big “if.”

Moyle and Baumsteiger raise important questions about extinction, official declarations of extinction, and their implications for fisheries and wildlife management and allocation of scarce conservation dollars.

Parallels between death and extinction

A death certificate is an official statement documenting the cause, date, and place of a person’s ultimate demise. It is signed by a physician.

If a lifetime could be likened to a sentence with a subject, object, and verb — action performed by a subject on an object — then a death certificate would be like the period at the end of the sentence. It connotes finality and closure.

But what happens when an entire species dies out? While extinction amounts to the death of a whole species or sub-species — that is, of each and every member of a population that share a common genetic inheritance and that can interbreed with one another in the wild — in California and the United States there is no formal declaration of extinction that corresponds to a death certificate.

Being absolutely certain of a species’ extinction is typically much harder than being certain of an individual’s death. There is often a good deal of lingering doubt as to whether or not all remaining individuals, down to the very last one, have in fact perished from the face of the Earth. This lingering doubt may engender a good deal of stress, tension, and even dispute.

Years ago my good friend Dave vanished while traveling and hiking in the Peruvian Andes. His father traveled to Peru in search of his missing son, and managed to track down and speak to a lady who’d sat next to Dave on a bus that dropped him off at a trailhead. This was the last known person to see him other than perhaps those who may have murdered or abducted him. No remains and no belongings were ever recovered from this remote place.

Tragically, my buddy’s parents went to their own graves years later still mourning their missing, beloved son.

In such awful circumstances, a person may legally be declared dead in absentia in spite of the absence of direct evidence of his or her death (e.g., a corpse or skeleton, or portions thereof). Typically, a declaration of death in absentia is made only when a person has been missing for an extended period of time and in the absence of any evidence to the contrary.

The situation we as a society face in the case of biological species or subspecies on the verge of extinction is more like the case of my missing friend. Rarely are extinctions as clearcut as they were in the case of Martha, the very last passenger pigeon to perish; when Martha, an “endling” or last of her kind, died in the Cincinnati Zoo in 1914, an entire species died out with her.

More often extinctions are like the sad story of the ivory-billed woodpecker (Campephilus principalis), last confirmed in the wild back in the 1940s, but claimed by at least some competent ornithologists and amateurs to have been observed as recently as this century. In 2010, the U.S. Fish and Wildlife Service released a recovery plan for this bird which may have already been extinct for three-quarters of a century.

Moyle and Baumsteiger conclude that:

[T]he best strategy is not to let any fish species go extinct. If a fish species does go extinct, despite our best efforts, then funds and water used to keep the species going should be redirected towards keeping other species from following the same extinction trajectory. But to avoid spending scarce conservation dollars on species that have already gone extinct, we need a policy in place that provides a pathway for declaring a species officially extinct.

By extension, this applies to conserving all species of flora and fauna that share Planet Earth with us.

Extinction, like death, may be a natural phenomenon — all species are doomed to die out sooner or later. Extinction occurred for eons before Homo sapiens swaggered onto the scene. But H. sapiens has now assumed the role of life’s executioner. Biologists estimate that the rate of extinction has increased one-thousand fold above the natural background rate since humankind took dominion of the Earth.

As I wrote at the end of my essay, “Overpopulation versus Biodiversity: How a Plethora of People Produces a Paucity of Wildlife,” in the 2012 book Life on the Brink: Environmentalists Confront Overpopulation:

Our species is unique, because here and now only we have the ability to destroy, or to save, biodiversity. Only we have the ability to care one way or the other. The destiny of all wild living things is in our hands. Will we crush them or let them be wild and free? Limiting human population will not guarantee success, but not doing so means certain failure.

Leon Kolankiewicz is a wildlife biologist and environmental scientist and planner. He is the author of Where Salmon Come to Die: An Autumn on Alaska’s Raincoast and the essay “Overpopulation versus Biodiversity” in Environment and Society: A Reader. He also is an Advisory Board Member and Senior Writing Fellow with Californians for Population Stabilization.

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