Devil’s carnation – a worldwide phenomenon

One of the world’s smallest fish populations is formed by the Devils Hole pupfish(Cyprinodon diabolis, Devils Hole pupfish). It numbers several hundred individuals, and since they live for several months, the number can change significantly from year to year. Moreover, it is smaller in spring than in autumn. We know this because every spring and fall, scientists from Death Valley National Park dive into their habitat to count the individuals living there.

Living conditions in the Devil’s Hole

Devil’s Hole, a geothermal spring located in Nevada, not far from Death Valley. The reservoir does not have the morphometry of a typical lake. Rather, it is a system of caves with a complex structure and hydraulic connections to the groundwater and oases of the Amargosa desert that are not fully known. The divers managed to descend roughly to a depth of 130 meters, but did not reach the bottom. Exploration fervor is dampened by the memory of several victims who never returned from there to the surface. The unexpected connections are evidenced by the fact that the reservoir experiences tsunamis even during earthquakes on the other side of the Pacific.

The cave system is 0.5 million years old, but opened to the surface around 60,000. years ago. During the glaciations, these regions were covered by extensive lakes, of which relics remain today. The current water table of the Devil’s Hole is a crack 22 meters long and 3.5 meters wide. The water maintains a temperature of 33 degrees Celsius year-round (although in full sunlight it reaches as high as 39 degrees Celsius at the surface) and is poorly oxygenated. Under such conditions, most fish would not be able to survive.

However, different species of carpenter beetles are adapted to live in such oases, and one of them has settled this particular one. Some estimate that this happened immediately after the creation of the open lake, while others shorten this period to just 1,000. years. This means that the pace of its evolution was fast or extremely fast.

Devil’s Hole fish diet

The Devil’s Hole ecosystem is poor. Apart from the devil’s carpenter, there are no vertebrates in the area, not counting the owls that appear here. However, their role for the ecosystem is not insignificant, as their spits are almost the only external source of nutrients for algae, fungi and few invertebrates. Carpentines eat everything they can get their hands on. Most of their digestive tracts are filled with calcareous matter of bottom sediments.

In second place are filamentous algae – torsions. However, they are difficult to digest and diatoms are considered the proper food. Occasionally you will get a goby, a clam, an amphipod, a snail, or possibly a protozoan. For a fish measuring 2-3 cm, this is enough. However, in winter, little light reaches the cave, which negatively affects the amount of algae available. For this, the carpaccio copes with the lack of oxygen by switching to alcoholic fermentation.

Devil’s carpenter – why are there so few of them?

The cave is deep and carp happen to enter deeper, but in practice they mainly use the shallow rock shelf (calling it a littoral would be an abuse), where their food lives and where they spawn. This means that the primary fish habitat is limited to a space 3.5 meters wide, 5 meters long and 30 cm deep. Therefore, it is impossible to sustain a larger population. Fertility is not high, nor is survival rate. Any disturbance can upset the ecosystem. The species is very genetically homogeneous.

Devil’s Hole since 1952. Is an exclave of Death Valley National Park. Access to it is limited, although incursions do occur. In the late 1960s. Last century, the area saw a surge in groundwater extraction for field irrigation. This resulted in a lowering of the groundwater level and, consequently, the water table in the reservoir. The space above the rock shelf has shrunk. The case went to the Supreme Court, which in 1976. ruled that the consequences of such an intake violate the basis of the national park, and thus federal law. One of the anthropogenic threats has been resolved.

Monitored every six months, the population fluctuated, but by the mid-1990s, the population was in the mid-1990s. The amplitude was between 200 and 250 in the spring counts. Suddenly, however, it began to fall and is now settling at around 90. In 2013. has dropped to just 35. Pressure from the beetle Neoclypeodytes cinctellus is believed to be one of the causes. It was first observed in Devil’s Hole in the last years of the last century. It is an insect about the size of a poppy seed. It feeds on eggs and can even hunt down fish larvae twice its size.

Devil’s Carpenter in numbers

Attempts to raise devilfish in alternate habitats are yielding poor results. Fortunately, over the past decade, the natural population has begun to increase. In August 2023. The desert was hit by Hurricane Hilary. Water inflow is a disturbance with unpredictable consequences. The wave may have destroyed the eggs – such cases have been reported before. The rains are also a source of pathogens. This time, however, they brought nutrients in amounts favorable to carp. During the spring count in 2024. 191 individuals were observed, the most since March 1999. Scientists monitoring this population approached these results with optimism.

Photo. main: Presumably Olin Feuerbacher/Public domain/Wikimedia Commons