LIVING FOSSILS OF

PUPFISH ONCE FLOURISHED IN PRIMEVAL SEAS. NOW THEY SURVIVE IN THE DESERT

BY DEIRDRE MCNULTY

verywhere you look Death barely enough to keep a saltbush' I feed on , plectonema, and E Valley is brown, dry, and alive. Yet, underground other found near the surface of dusty. You can see for miles, yet sustain many seeps, springs, and ' the water. there isn't much to see except wide- shallows in this desiccated valley. open spaces, chemical desert, and These pools are home to several spe- wls—barn owls, great horned scrub. The air parches your skin and cies of ; and each habitat of- 0 owls, and others—provide a throat, and your eyes squint against ten has its own endemic species, vital link in the pupfish food chain. the hot bright sun. It is in this arid some just a few hundred yards from Owls that nest on rocky outcrop- environment, almost barren of vege- each other. pings above Devils Hole drop cast- tation, that the pupfish lives. were originally dis- ings into the water, which provide . in ? Yes, and covered in 1898, but it was not until many nutrients that promote algal they've been there a long time, long - scientist Carl Hubbs began studying growth. enough to provide scientists with a the fish in the 1930S that they got As with most vertebrates, male window to the Pleistocene Epoch their common name. Their playful pupfish are far more colorful than and some insights into the develop- behavior reminded Hubbs of pup- the females. Coloring varies from ment of certain human regulatory pies, and thus the name. species to species, but usually males organs. The best-known species are the are royal blue, becoming iridescent During the Pleistocene, which Devils Hole pupfish, the Salt Creek when excited, agitated, or breeding. ended 10,000 to 20,000 years ago, pupfish, and the Cottonball Marsh Males also have dark striping and what is now desert was covered by a put sh. All of them, and their habi- violet gill covers. Females are a dull lake, posthumously named Lake tat -e protected as part of Death yellow-brown with a silvery under- Manly. Approximately 175 miles VAL National Monument. side. long and 600 feet deep, nese species, the Devils Hole Devils Hole pupfish lack stripes covered virtually all of Death Val- pu- ,n is the only endangered one, and pelvic fins that the other species ley; and flourished. Over the say iom Baugh, fisheries biologist have. They are also unique in that centuries, the dimate warmed, gla- for the U.S. Fish and Wildlife Ser- their heads are large in proportion to ciers receded, and southeastern Cali- vice. There are, however, other en- their bodies. Scientists speculate fornia became dry, causing the lake dangered species found outside the that once flooded Death Valley to national monument. PUPFISH, because of their ability to evaporate. Pupfish are small—they measure adapt to varying levels of salinity, are Today the average annual rainfall about one to two inches in length, providing information that assists sci- in Death Valley is only 0.7 inches, ' and Weigh only a few grams. They entists with kidney research.

14 NATIONAL IRKS 0 SEPTEMBER/OCTOBER 1956 that, because of its smaller size and One of these tanks is located just large head, the Devils Hole fish is a below , the other is less dwarf species. As creatures of than a mile from Devils Hole. Devils Hole is the strangest, but another time, pupfish There has also been considerable most well known of the pupfish effort to culture the Devils Hole habitats. On the surface, this pool of have given scientists pupfish in aquariums. To date, these sweet water appears small—only insights to life attempts have been less than suc- seven by three meters—and is sur- cessful. Only two aquarium- rounded by rock. The fish feed and on Earth during spawned fish have been raised. on a rocky shelf that lies just the Ice Age. Salt Creek, which flows through inches below the surface of the wa- the central part of Death Valley, is ter. But, below this shallow, rocky the home of the Salt Creek pupfish. shelf, Devils Hole drops off sharply Although McLean Spring, the source into underground catacombs. cently. Although Devils Hole was of Salt Creek, is watered by snow- At about 80 feet below the sur- included as a noncontiguous unit of melt and rainwater, by the time it is face, under an outcropping called \ Death Valley National Monument in forced to the surface through a rock Anvil Rock, the main cavern opens I 1952, the fish's endangered status fault, the water has already become into an immense chamber. Several - I was made more precarious by pro- highly saline. arms branch off of the main cham- posed development in Ash Mead- ber; and, in one, researchers are able ows, which surrounds that section of lthough the Devils Hole spe- to remove their SCUBA equipment the park and has since been desig- A cies is the only endangered and breath from an air pocket at the ) nated as a wildlife refuge. pupfish within the monument, the top of the submerged cave. "Ash Meadows' aquatic habitats Salt Creek pupfish—and the have been drained, channeled, Cottonball Marsh pupfish—are re- ccordirtg to Baugh, who has dammed, and, in some cases, markable for their osmoregulatory A conducted census counts in pumped dry," stated Baugh. abilities, which allow them to live in Devils Hole, the pupfish population At one point, the area was in dan- water that is five times the salinity fluctuates between 150 and 600 indi- ger of being turned into a city of va- of sea water. viduals. He says the fish have been cation homes, jeopardizing 20 to 30 • During the dry season the amount found as far down as 80 feet, but other species of endangered plants of water in Salt Creek declines and they generally stay near the surface and . If development had the pupfish population can drop to and the rocky shelf. A few also have ; been allowed in Ash Meadows, the about 1,000. During the cool part of been found in branches of the main groundwater that supplies Devils the year, however, when greater chamber, but Baugh believes that Hole would have been used up. In quantities of fresh water move down the fish may have been blown into 1976, however, the Supreme Court the stream channel, the population these areas by divers' air bubbles. ruled that the water in Devils Hole can increase to as much as 1,000,000. Typically, for a desert pool, Devils must be maintained at a certain level The adaptability of these fish to Hole is watered by underground to allow the fish access to the rocky changing salt content has provided aquifers. Rainwater falling on the shelf where they feed. medical insight, especially in the ar- surrounding areas percolates down eas of kidney dialysis and transplant through the ground until it is hil Pister, fishery biologist research. stopped by a solid rock base ap- P with the California Depart- In addition, a great deal about proximately 300 to 500 feet below ment of Fish and Game, points out, evolution can be learned by study- / the desert floor. "The key to long-term preservation ing these tiny fish. As creatures of Water that has been collecting lies in habitat integrity!" another time, pupfish have given over millennia in these aquifers bub- After nearly losing prime pupfish scientists insights to life on Earth bles up through fractures or faults habitat in Ash Meadows to develop- during the Ice Age. and forms pools. The "fossil" water ers, scientists realized it was impera- Their benefits to humans are cer in Devils Hole fell as rain on what is tive to scatter the pupfish popula- tainly a factor in protecting pupfish. now the Test Site—a nuclear tion. They wanted to make sure that But, as Phil Pister said, "Any ratio- test site that forms a large chunk of if the Devils Hole population was nale we present to save species and southern Nevada—about 10,000 decimated, due to either natural or habitats should be based less upon years ago. Trickling slowly through man-made disasters, the species potential benefits to man than upon substrata, the water has taken that would not become extinct. the inherent capabilities given to us long to travel the approximately 50 With that in mind, fish were in having a conscience and know- miles between the Nevada Test Site transplanted to two refugiums. This ing—deep down—that it is the right and Devils Hole. was done, according to Baugh, "so thing to do." The Devils Hole pupfish, a sort of all our eggs aren't in one basket." living fossil itself, has survived the These refugiums are large concrete Deirdre McNulty is assistant editor of centuries unmolested—until re- tanks especially built for pupfish. National Parks magazine.

NATIONAL MKS 0 SEPTEMBER/OCTOBER 1986 17 Right: A rocky shelf near the surface of Devils Hole creates a shallow pool where pupfish feed and spawn. Below the shelf are flooded caverns of un- known depths. The instrument at the right of the pool measures the amount of sunlight falling on the surface of the water.

Below: A penny puts the size of anes- thetized Cottonball Marsh pupfish into perspective (top to bottom: immature pupfish, male, female).

Bottom: University of Nevada's Dr. James Deacon, "Dean of Pupfish," studies some Devils Hole pupfish that were transplanted to a refugium just south of Hoover Dam as a hedge against .

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