An "Extinct" Fish Finds Life Again in a Parched Desert: The Saga of the Shoshone Pupfish

The pupfish habitat at the springs in Shoshone, east of Death Valley National Park

Of all the things one might look for while exploring intense desert environments, what is the most unlikely form of life you would expect to encounter? Fish of course. It's practically an oxymoron to use the term "desert fish". But in the harsh desert environments of eastern California and western Nevada, there are indeed fish. And not just a single species, but around a dozen species and subspecies. There are nine distinct populations of the Cyprinodon Pupfish, three species of Speckled Dace, and a Poolfish. How they survive today, and how they got there in the first place is a fascinating story.

How they survive is not difficult to understand: despite the aridity of the California desert, there are sources of water. There are permanent springs and pools of water scattered all around Death Valley and the Amargosa River Basin, and the fish have adapted to life in waters that might be hot, cold, fresh, or salty.

How they got there in the first place is a little trickier to understand. Our climate has been subject to huge variations over the last two million years, and more than a dozen times, it got much cooler and glaciers developed and expanded, especially in the Sierra Nevada mountains. Some of the meltwater from those glaciers flowed into the deserts of the Basin and Range province and accumulated in huge freshwater lakes. As a lake basin filled (such as at Mono or Owens Lake), it spilled over into the next lake basin until a network of lakes extended from the Sierra Nevada to Death Valley. The Amargosa River flowed through western Nevada, also ending in Death Valley. So there was plenty of water once upon a time.

At some point in time, a connection was made with the Colorado River, and fish were able to make their way into the network of freshwater lakes, and they thrived. But as each glacial stage ended, the lakes would begin drying up and most of the fish lost their habitat and went extinct. But those very few species that could adapt quickly enough took refuge in the rare and isolated springs and pools. A few, including the Lahontan Cutthroat Trout survived in the cold streams, lakes and rivers of the eastern Sierra Nevada. Those trapped in saline waters had to adapt to the salty conditions. Some fish adapted to high temperatures,  and unlike pretty much any other fish in the world can survive in water that reaches a hundred degrees or more.

One of my very few photos of the Devils Hole Pupfish, taken from around 100 feet away.

Perhaps the most famous of these fish is the Devils Hole Pupfish (above), found in a single cavern opening in the Ash Meadows National Wildlife Refuge (the spring officially lies in an outlier of Death Valley National Park). Their story is compelling, but they are not the fish I'm discussing today. You can read about them if you wish here or here.

 

The various populations of pupfish survived for thousands of years in isolation from human developments. But the colonization and occupation of the desert by miners and ranchers spelled doom for some of them. One species, the Tecopa Pupfish, was driven extinct pretty much in an afternoon when pipes were installed at the one spring where they lived. A similar fate apparently happened to a different subspecies, the Shoshone Pupfish (Cyprinodon nevadensis shoshone) in the 1960s as springs in that area were developed for domestic use at the village of Shoshone. The species was declared extinct in 1969, as none could be found anywhere.

Improbably, a small population of the fish actually survived the devastation of their original habitat by taking refuge in a nearby irrigation ditch, unnoticed by anyone. In 1986 they were rediscovered, and a cooperative effort by the private landowner and several environmental organizations resulted in a resurrected habitat. This habitat was actually expanded to three pools and some artificial off-site refuges as well. Despite visiting Shoshone yearly for the last three decades, I never heard about the efforts being made on behalf of the fish's well-being. 

That changed last week when I found out that a nature trail had been constructed, and interpretive signs posted that allowed for some close viewing of the diminutive fish (as well as another highly endangered creature, the Amargosa Vole). The site also serves as an excellent habitat for a large variety of birds, and we saw Western Bluebirds, Yellow-rumped Warblers, White-crowned Sparrows, a Costa's Hummingbird (a life-lister for me) and we could hear Verdins chattering away in the brush.

The trail is just off the main highway in Shoshone, and the locals seem proud of the efforts and can easily point the way to the trailhead, next to the local school. If you ever travel to Death Valley from the east, you can't miss the town. It's the only gas station and food stop for many miles. Don't forget to stop in at the local museum for a look at the Columbia Mammoth fossils on display inside!