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Devil’s Hole Pupfish Further Endangered by Rising Temperatures

Living in a desert environment is difficult for any species but, one has to imagine, it’s particularly difficult if you’re a fish. Take, for instance, the inch-long iridescent-blue fish that calls a limestone cavern in the floor of the Amargosa Desert it’s home: the Devil’s Hole Pupfish. Here in a spring-fed cavern that’s 426-feet deep and only has a small opening to the outside world the entire population of the Devil’s Hole Pupfish lives out their short, year-long life-spans, as they have for the last 10,000 years.

First granted protection in the 1970s, when the population of Pupfish was more than 500, the pupfish population is now down to 92 members. Over the last forty years the pupfish has suffered a number of population setbacks. A flash flood in 1973 scoured the algae that the fish depend on for both food and breeding from the ledge.

An earthquake in 1978 caused waters to surge and, again, remove the algae. Starting in the mid-1990s the pupfish began declining due to factors unknown, which was compounded when a flash flood washed scientific equipment in to Devil’s Hole in 2004 and killed an estimated 80 fish just as the population was beginning to recover.

More recently researchers have begun to notice a disturbing trend: the geothermal water which feeds Devil’s Hole has begun warming, registering as high as 97 degrees at times, very near what the highest temperature the Pupfish can breed in on the shallow shelf that serves as both breeding ground and feeding ground. The warming water has begun to shrink the the short 10-week hatching widow, already subtracting a week of time over the past two decades. In the past Devil’s Hole was cooled by the ambient air temperature, which, on average, was lower than the water temperature. However, data indicates that there are more days with higher temperature, lending scientists to believe that the warming trend in Devil’s Hole will only get worse.

Although attempts to breed Devils Hole Pupfish in the past were unsuccessful, a recent 2013 breeding program at the brand new Ash Meadows Fish Conservation Facility hatched 33 larvae and raised 29 of the fish to adulthood. They have been released into a specially built refuge tank that closely mimics the habitat found in Devil’s Hole and, since their release, spawning behavior has been observed.

For more information check out the Nevada Fish & Wildlife Office and from Death Valley National Park.