Claim: Climate change puts endangered Devils Hole pupfish at risk of extinction

From the University of Nevada, Reno | A claim that more likely has to do with natural drought cycles, fresh water influx,  and the PDO than it does with the universal boogeyman “climate change”.

University of Nevada, Reno and Desert Research Institute research shows rare fish struggling to survive


RENO, Nev. – Climate change is hurting reproduction of the endangered Devils Hole pupfish, threatening the survival of this rare species that has numbered as few as 35 individuals, new research by the University of Nevada, Reno and Desert Research Institute shows.

Scientists report that geothermal water on a small shelf near the surface of an isolated cavern in the Nevada desert where the pupfish live is heating up as a result of climate change and is likely to continue heating to dangerous levels.

The hotter water, which now reaches more than 93 degrees, has shortened by one week the amount of time pupfish larvae have to hatch during the optimal recruitment periods. The recruitment period is the 10 weeks during which water temperatures are conducive to egg hatching and sufficient food is available to sustain the newly hatched larvae. This decrease contributed to the decline of the adult pupfish population, according to a scientific paper published in Water Resources Research, a journal of the American Geophysical Union.

Caption: Scuba divers conduct fish research at Devils Hole, an isolated geothermal water-filled limestone cavern in the Nevada desert. The aquifer-fed pool in the Ash Meadows National Wildlife Refuge, a detached unit of Death Valley National Park, is the habitat for the only naturally occurring population of the endangered fish. It is an extreme environment, with water temperatures and dissolved oxygen concentrations near their lethal limits for fish.

“Climate change is making it harder for the Devils Hole pupfish to survive and has most likely contributed to the decline we have seen,” said Mark Hausner, a hydrologist at the Desert Research Institute in Las Vegas, Nev., and lead author of the paper, “Life in a Fishbowl: Prospects for the endangered Devils Hole pupfish (Cyprinodon diabolis) in a changing climate.”

Devils Hole, in the Mojave Desert, will also likely become less hospitable to the pupfish as climate change continues to warm the planet, he said. The new research found that increasing temperatures will likely reduce the pupfish’s optimal recruitment period by another two weeks by mid-century. Higher temperatures could also affect the availability of food for young pupfish, leading to fewer adult fish.

“There is no question that the temperature is going to rise on the shallow shelf, and there is no question that the fish are going to be affected,” said Scott Tyler, lead scientist in the project, co-author of the paper and a professor of hydrological sciences at the University of Nevada, Reno.

“While the population of the pupfish has declined, we are hoping they are in a period of recovery,” Kevin Wilson, aquatic ecologist and a member of the research team from the Pahrump Field Office of Death Valley National Park, said. “Climate change is threatening the already small population size.”

Devils Hole is a water-filled limestone cavern in the Ash Meadows National Wildlife Refuge, a detached unit of Death Valley National Park. It is an extreme environment, with water temperatures and dissolved oxygen concentrations near their lethal limits for most fish.

The iridescent blue, one-inch-long pupfish have lived in the top 80 feet of the water-filled cavern for more than 10,000 years.

There are now 92 Devils Hole pupfish observed living in the geothermal pool. The population, which fluctuates throughout the year, is down from 171 fish a decade ago (according to seasonal counts). The population is down from 553 fish when the population counts began in 1972, according to the National Park Service.

“This is a fish that does live in a fishbowl, an incredibly hostile fishbowl, and you can’t move the fishbowl,” Tyler said. “This is a species that can’t adapt or change or leave to go to a better environment, though it’s most likely gone through tremendous genetic bottlenecks in its more than 10,000 years of evolution.”

Tyler and his team, with grants from the National Park Service, Nevada Department of Wildlife and the Death Valley Natural History Association, used fiber-optic cable distributed temperature-sensing equipment, pioneered by Tyler, to monitor temperature changes in the more than 400-foot deep geothermal fissure in the desert. They used current and historic data to create a numerical model, using the same equations used in fluid dynamics and aerodynamics for designing Formula-one race cars and airplane wings, to chart thermal mixing of the water within the aquifer.

The scientists combined climate projections, models of water circulation in the deep, water-filled fissure, and food web ecology to understand how climate change could affect the ecosystem within the pool. The model estimated optimal pupfish spawning periods based on projections about how much the environment will change and how much food will be available under different climate scenarios.

“The techniques used to model the impacts of climate change for the Devils Hole pupfish can be applied to other species in other desert locations to see how they might respond to the changing climate,” Tyler said.


The research team includes Kevin Wilson and Bailey Gaines of the Pahrump Field Office of Death Valley National Park; Francisco Suárez from the Pontifical Catholic University of Chile; and Gary Scoppettone of the Western Fisheries Research Center of the United States Geological Survey. The American Geophysical Union posted a similar story about the research on their GeoSpace blog at on the AGU Blogosphere at

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Mike T
August 28, 2014 8:19 pm

This species relies on geothermally heated water. How would air temperatures affect them, even given that the area has actually warmed (which is not proven)?

Reply to  Mike T
August 29, 2014 7:06 am

Viva Las Vegas.

Because of geothermal activity, Nevada is home to about 300 hot springs. Here are just a few:

I have found out that the cave is susceptible to disturbance from earthquakes occurring far away. An they were formed 500,000 years ago.
Q)Could this be bringing hot water up faster?

Devils Hole is a window into this vast aquifer and an unusual indicator of seismic activity around the world. Large earthquakes as far away as Japan, Indonesia and Chile have caused the water to ‘slosh’ in Devils Hole like water in a bathtub. Waves may spash as high as two meters up the walls, sweeping clean the shallow shelf so important to the pupfish.
Watch this YouTube video of a ‘tsunami’ in Devils Hole caused by a 7.4 magnitude earthquake in Oaxaca, Mexico on March 20, 2012. Learn more and see another video in this Scientific American article.

James the Elder
Reply to  Mike T
August 29, 2014 8:44 pm

Aha!! That’s where Hansen’s heat is going.

stan stendera
August 28, 2014 8:20 pm

As a solid environmentalist I cannot help but wonder if all the research into the poor pupfish is causing their decline.

grandpa boris
Reply to  stan stendera
August 28, 2014 11:10 pm

Yes, research did (indirectly) contribute to the recent decline. A decade ago negligence of the researchers had resulted in deaths of a large number of fish:
These fish is that they evolved for their unique habitat. They are related to other Cyprinodons native to the Death Valley. At some point in the last 20K years, as the water levels in the giant lake that filled that area shrunk, they became isolated in a small pool located in an earthquake-caused fissure in a porous limestone outcropping, Today this pool is fed by groundwater. Their primary food source on algae that grows on limestone rocks in the Hole. The hole is deep, well over 90′, and connects to other underground water-filled chambers, so there is water there for the fish to retreat to if water levels drop. But their food source would be severely constrained.
What is scientifically remarkable about these tiny, very attractive fish, is that despite being confined to a pool with a surface area of a medium sized hot tub, they had not experienced genetic degradation from inbreeding and reproductive isolation.
These fish were critically threatened in the 1970s by the pumping of the ground water from the aquifer that feeds the Hole. The water was used to irrigate nearby cotton fields. The Hole was going dry. The pupfish population reached the lowest point right before they were listed as critically endangered and the ground water pumping was constrained (which didn’t please the farmers).
Like other pupfish in the Death Valley, Cyprinodon diabolis can survive in very warm water. “Global warming” will threaten their survival only it sufficiently affects the rainfall outside of the Death Valley, and that stops the flow of the water that drains into the Valley and feeds its springs and highly saline and alkaline lakes. As you correctly wonder, stan, humans’ attention and inattention are probably a much greater threat to the pupfish than the climate change, whether man-made or natural.

August 28, 2014 8:20 pm

In the desert.

August 28, 2014 8:26 pm

There are around 10 MILLION species of animals on Earth.
Extinction is a natural process that has been going on for Billions of years.
There have only been about 50 animal extinctions over the past 100 years, and not ONE can be attributed to Global Warming. They’ve been caused by: over hunting, introduction of non-indigenous species, habitat destruction, etc…
I can’t believe the CAGW acolytes still use this silly “CAGW mass extinction” meme, when there is absolutely no empirical evidence to justify it…
This “unprecedented CAGW extinction” (TM) meme is complete hokum used to scare and deceive “useful idiots”, that will believe whatever they’re told to believe, regardless of empirical evidence that negates their blatant propaganda.

Reply to  SAMURAI
August 28, 2014 9:24 pm

You are missing The Point. This potential extinction is linked to Climate Change, so it is OUR FAULT!

Adam from Kansas
August 28, 2014 8:28 pm

Heh, now that’s a possibility, the pupfish going extinct because their pool is getting continually disturbed by the boatloads of researchers studying and counting them, nothing to do with climate.
Or maybe it does have to do with climate, does anyone know if there’s a correlation between the number of researchers in the pool and the temperature?

Reply to  Adam from Kansas
August 28, 2014 9:23 pm

Between your and Stan’s comment and my own thoughts, I counted at least 5 researchers in the pool and at their body temps would have lowered the water temp besides the fact there is contamination of all sorts on their diving gear (oils etc).

James the Elder
Reply to  asybot
August 29, 2014 8:47 pm

Water temp 93F, body temp 98.6F. The divers are killing the fish by raising the temperature. Not to mention the extra CO2 being discharged into the water.

Leon Brozyna
August 28, 2014 8:35 pm

Such an eye-roller moment it hurts.
You mean that in thousands of years the climate never experienced more severe conditions than at present, such as during the megadroughts of the Medieval Warm Period, when it was warmer and dryer than at present?
Next thing you know, they’ll be anointed as our new “canaries in a coal mine”.

August 28, 2014 8:36 pm

It’s a big aquarium. Control the temperature and sparge air into the water for oxygen.

george e. smith
August 28, 2014 8:43 pm

Well get a class of about 20 fourth graders, and some worms, maybe a gallon of ice cream, and they’ll get all of those pupfish out of that boiling hole, then we won’t have to worry about them any more. They probably taste just like chicken.

mark l
August 28, 2014 8:51 pm

” Climate change is hurting reproduction of the endangered Devils Hole pupfish, threatening the survival of this rare species”
Once again someone gets published because they support the doom and gloom inevitability of AGW. The certainty they use makes the average person believe it’s true and not just another theory, to support another theory. But I believe most people are catching on because a common satirical retort to something/anything going wrong is “climate change caused it”.

Mike Tremblay
Reply to  mark l
August 28, 2014 9:14 pm

How else are you going to get research grants for such marginal areas of research if you don’t get on the Climate Change Gravy Train?

August 28, 2014 9:04 pm

Provided governments continue with halfhearted reactions to the CAGW creation without going overboard we can be tolerant. I have to admit that it has led to a few good environmental decisions and technological developments.
A side effect of the CAGW scare is entertainment. Many of the claims are so ridiculous that they are just downright funny (extinction of the coffee plant (panic!), melting of the earth’s mantle and the increases in insurrections because it’s too darn hot were some of the more memorable ones for me).
Other claims, such as this story, are simply sad and disturbing. How can a scientist with any credibility and sensitivity justify the amount of disruption to the habitat that this picture shows, and without any logic or proof make the claims that they have. These are not scientists, and we will lose another species not because of CAGW but because Dr. Billy-Bob accidentally blew the last specimen out his snorkel.

Richard G
August 28, 2014 9:17 pm

My first bit of skeptism began when I saw it was a geothermal pool. Then I saw they used climate projections in their study. Those wouldn’t be from the same climate models that have been overestimating temperatures would they?

August 28, 2014 9:27 pm

I wonder if the pupfish react to the urine the divers leave in there(I sure don’t see any portapotties in that environment, and they really should drink a lot a water in Death valley.) And what of the effect of the divers skin oils, deodorants, soap and shampoo on the water quality? The neoprene wetsuits?
Remember what they did to all those endangered desert tortoises when they lost funding? Hundreds were euthanized. Probably best to just leave them alone to die.

August 28, 2014 10:19 pm

‘“There is no question that the temperature is going to rise on the shallow shelf, and there is no question that the fish are going to be affected,” said Scott Tyler, lead scientist in the project, co-author of the paper and a professor of hydrological sciences at the University of Nevada, Reno.’
“There is no question … ” Huh? This is a scientist?

Reply to  DesertYote
August 29, 2014 5:28 am

My thought exactly….. If the pup fish goes, will the dog fish be far behind.

August 28, 2014 10:27 pm

There are now 92 Devils Hole pupfish observed living in the geothermal pool. The population, which fluctuates throughout the year, is down from 171 fish a decade ago (according to seasonal counts). The population is down from 553 fish when the population counts began in 1972, according to the National Park Service.
“This is a fish that does live in a fishbowl, an incredibly hostile fishbowl, and you can’t move the fishbowl,” Tyler said. “This is a species that can’t adapt or change or leave to go to a better environment, though it’s most likely gone through tremendous genetic bottlenecks in its more than 10,000 years of evolution.”

Genetic bottlenecks” means the population was nearly wiped out so badly it removed genetic diversity on more than one occasion. When this happens due to one constraint, the remaining genetic pool may lack the robustness to overcome another constraint.
After one, the natural course is either a population recovers or it goes extinct. They say the species cannot adapt or change, thus likely it is highly inbred, genetic diversity about nil. Extinction is thus the likely natural result.
Why do people who care so much about “Nature” fight so hard against what is natural?
More than 10,000 years of evolution? Practically nothing. That sounds suspiciously like the start of the current interglacial, as if this was a population left behind during the warm-up. Seems most likely they could be traced by their genes and shown to be a genetic subset of a species found elsewhere, that has large and healthy populations.

August 28, 2014 10:52 pm

This propaganda dressed as science did not bother to mention that almost all declines in C.diabolis can be directly attributed to the activities of researchers, as some commentators have speculated. Sometime in the mid 2000’s, one third of the population was wiped out by equipment that researchers had left behind washing into the sink during a flash flood.
BTW, 94F is not unusual at all.

Reply to  DesertYote
August 28, 2014 11:57 pm

Thanks DesertYote for the info- I came across this article which mentions “researchers” looking into a variety of reasons for the decline- (
“Other factors the researchers are examining include changes in water chemistry, changes in algal communities that might impact the amount of dissolved oxygen available to fish (already low), or a phenomenon called “inbreeding depression,” which basically means pupfish are not reproducing successfully because they lack the genetic diversity to avoid deadly mutations. ”
I’m curious of the results of any of this other research? or is the AGW temperature theory the only one getting press? Another article talks about them originally being part of a fish that had been in this pool since ice was in the valley? It sounds like they’ve “adapting” thru many changes over 40000 years, so really, we should believe that climate change is the most likely explanation for their numbers to be low? Wow. This paper was peer reviewed?

August 28, 2014 11:01 pm

The Devil’s hole pupfishFish can’t cope with climate* ? Sooo the fish obviously went extinct during the Holocene optimum, the Minoan warm period , the Roman warm period and the Medieval warm period and has recovered from being dead just in time to go extinct again ?
* ( change is implied , there’s no such beastie as a static climate )

August 28, 2014 11:08 pm

kadaka (KD Knoebel)
August 28, 2014 at 10:27 pm
The concept of genetic bottleneck does not really apply to many families in Cyprinodontiformes. The scientist responsible for second paragraph in your quote was incredibly ignorant or deliberately misleading. One of the problems with this species is that attempts to establish refugia populations sometimes fail, because the species soon adapts to new conditions. That is how C. macularius complex species managed to flourish in the desert. It adapts and adapts rapidly.

Reply to  DesertYote
August 28, 2014 11:28 pm

So these are only relatives of common aquarium fish? What’s next, climate change threatening a historic pond of goldfish?

Reply to  DesertYote
August 29, 2014 5:28 am
Reply to  Bob Greene
August 29, 2014 11:03 am

Which is pretty good considering the number of failures. Most failures are not due to the inability of a population to be established, but rather that the established population does not stay true to type. The standard evolutionary model does not apply very well to this group. These fishes are genetically predisposed to adapt to a wide range of conditions. That is how they have managed to flourish in the desert. Take C. macularius for example. Establish populations in a number of isolated habitats with widely divergent conditions. Come back in 100 years, and you would have what would be considered different species according to current criteria.
Cyprinidontiformes contains some of the most amazing examples of adaptation of any group of fishes.

August 28, 2014 11:15 pm

One of the main constraints on the population of all species of Cyprinodon, is water volume. These are nasty and highly aggressive fishes that will tear each other to shreds when they get to crowded.

Joel O’Bryan
August 29, 2014 12:20 am

Just like the glaciers of West antarctic peninsula, those water hole have been living on borrowed time as the climate warmed.
That is the sinister beauty of the term Climate Change. We want to think that the earth has been and will always be as it was in the 20th century. And when it is not in the 21st, we naturally look for a cause. Warmunistas realized that fallacy and renamed global warming to climate change. Diabolical.
bye bye fishies. hello CAGW.

M Courtney
August 29, 2014 12:46 am

Evolution or Extinction.
Don’t they teach Darwinism at the University of Nevada?

Reply to  M Courtney
August 29, 2014 1:10 am

Didn’t You get the memo ? That old fashioned science is sooo uncool with it’s testable (and thus challengeable ) hypotheses built on observations , it’s all new age psuedoscience now where species , like climate , have all stopped evolving/changing .

August 29, 2014 2:02 am

Saving endangered species is just one more arrogant attempt by man to control nature. Its arrogant meddling. If nature wants this fish gone, then let it go gracefully, doesn’t anyone understand this type of meddling is what got us all these problems to begin with….George Carlin

Mike T
Reply to  pissedman
August 29, 2014 2:22 am

So trying to prevent Japanese whalers killing whale species such as the Humpback is a waste of time? Or allowing poachers full access to national parks in Africa to hunt rhino so their horns will find their way into Chinese aphrodisiacs is good?

M Courtney
Reply to  Mike T
August 29, 2014 2:26 am

Is there not a difference between human actions and things that happen anyway?
If man is responsible then we have already made nature into a garden and have accepted a duty of care.
But if it’s happening anyway… do we have such a duty of care?
If we do then we seem to be denying the right of anything to exist except for the desire of man.

Reply to  Mike T
August 29, 2014 5:13 am

Congratulations on so spectacularly missing the point!

August 29, 2014 2:22 am

There are two gaping holes in this research,
How did the scientists involved feel about the fish ? what were their emotions ?
How scared were they, were they scared a bit, a lot , scared witless ?

August 29, 2014 3:42 am

wonder how much? money
and how long for?
these idiots have been wasting time an tax funds on a bloody fish that serves NO useful purpose at all to anyone?
and btw theyre in a nice closed spot dont birds and other critters like a fishy meal every now n then?

August 29, 2014 3:58 am

Poor evolutionary choices have consequences. 😉

August 29, 2014 4:28 am

If we want to protect the Pupfish, instead of limiting our CO2, perhaps we should limit our government research grants.

August 29, 2014 5:14 am

More drivel.

Steve in SC
August 29, 2014 6:12 am

Probably not even good bait.

August 29, 2014 6:55 am

There are now 92 Devils Hole pupfish…..
and they have been line bred for thousands of years
…and the idiots wonder why they are in decline

Reply to  Latitude
August 29, 2014 11:21 am

The concept of “line breeding” does not apply very well to desert fishes in general. They have evolved to stay very stable with small isolated populations with the ability to change rapidly when conditions change. Don’t put much stock in these cited population numbers. They are cherry picked. In any given year, the population can range from 400+ to 70. The only real limit on numbers is water volume.

August 29, 2014 7:04 am

This species is trying very hard to go extinct. Let’s just let them go quietly into the night. As a heavily inbred species, it is amazing they are here at all.

Richard Ilfeld
August 29, 2014 7:24 am

Hey, it would probably only cost a few billions of dollars to divert some water from Kalifornia and crossbreed the critters with the Delta Smelt. We’d have a more robust species in a bigger fishbowl. Course we’d have to add a billion to build an earthquake spillway under the high speed rail line, and some fish-neutral pumps to get the water over the mountains, but nothing is too good for our friends the pupfish. I remember having one as a kid. breaded, on a stick, at the county fair. Yummy.
Do I really, really need a /sarc tag?

August 29, 2014 7:51 am

Yesterday I found two garter snakes in my shed. I think it is due to global warming.

August 29, 2014 7:54 am

OMG! Not the Devils Hole pupfish! There I was worrying about the New World Order, Gaza, Ukraine, Ebola, vaccinations, Smart Meters and other stupid stuff.

August 29, 2014 7:56 am

I wonder how well they’d do as a warm tank species in the aquarium trade…

Reply to  mjc
August 29, 2014 11:27 am

Not to well. They are a bit of a pain in the butt. Experienced fish keepers on the other hand would find them worth the effort, but moon bat legalities are preventing anyone from owning them except the benighted few. Lefties HATE the pet trade and do everything within their evil power to destroy it.

August 29, 2014 9:05 am

I recall that biologists were making a good living fretting over pupfish forty years ago when I first visited Death Valley. Some things never change.
Pupfish angst is a career for some fortunate academics.

Reply to  Billy
August 29, 2014 11:47 am

You are talking about C. macularius in the Salton Sea. This is really funny as the population there is the result of a man caused flood that greatly expanded its habitat. All of the hand wringing was over Archocentrus nigrofasciata. The goal was to use the plight of the pupfish as a pretext to go after Aquarium hobbyists.

Reply to  DesertYote
August 29, 2014 1:08 pm

I guess that is why we don’t remember the “Aquarium Hobbyist Insurrection”.
Put down by good planning !
Anyhow… the article says that ” climate change could affect the ecosystem within the pool.”, and syas “they ” know how, but I am not seeing it.
It’s a hot spring fed from underground in a cave. I don’t see the connection to anything that passes for “climate science”. Apparently it is just too attractive to hitch your wagon to the AGW foodchain rather than admit you are doing geology or biology, or research into some other field.

August 29, 2014 1:22 pm

Reminds me of the the press releases (that were called scientific papers, pal reviewed no doubt) that showed climate change was causing viruses in toads or frogs. Turned out that the viruses were introduced by the “researchers” who were studying them. Same with penguins in Antarctica. Seems the “researchers” will study every species until they are all killed off by the caring researchers. Or until the money (grants) runs out, whichever happens first.

August 29, 2014 9:34 pm

If you go to Furnace Creek from LV/Pahrump. you go right by Ash Meadows. Really interesting place. There are several springs with a total output of 10,000 gpm. There is no outflow, with a reservoir and some reclamation projects (it was a farming area) taking the surface water.
BTW, there are three species of pupfish at Ash Meadows.

Robert Landreth
September 1, 2014 11:25 am

As a Geology student at UNLV in the early 70’s the pup fish were threatened then due to water being taken for irrigation. They transplanted some of the fish to a warm spring near the Colorado River but they became much larger due to better living conditions. I also remember Devil’s Hole was entered illegally by two divers who never returned. The water was in the 90’s and you hardly know you are in water due to the temperature. The two scuba divers went down and failed to use a line to follow back to the entrance of the hole. Search teams spent several days trying to locate the two divers, but they were never found.

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