'Mysterious' fish species: There were 37 fish left, living in Devil's Hole, conservation costs amounted to more than 90 billion VND

This strange fish is estimated to have fewer numbers than even pandas. They live in Devil's Hole, a place in Death Valley in the US with an extremely harsh climate.

Previously, pandas were included in the endangered species list. However, thanks to the efforts of conservationists, recently, the number of pandas in the wild has reached more than 1800 ones living in the wild. Few people know that, in the world, there is a fish that is more precious than pandas because their number is currently only close to 200. What kind of fish is that?

Special place to live

At a place called Devil's Hole in an isolated area of ​​Death Valley National Park located between the US states of California and Nevada. According to Wikipedia, Devil's Hole is a geothermal pool in a limestone cave in the Amargosa Desert in Nevada's Amargosa Valley, east across the Amargosa Mountains and Funeral Mountains from Death Valley. It is 730 m above sea level and the water has a constant temperature of 33 degrees Celsius.

The entrance to the Devil's Hole in Death Valley National Park, USA. (Photo: Dri)

The surface area of ​​Devil's Hole is about 22 m long x 3.5 m wide. About 0.3 m deep at one end of Devil's Hole is a small 3.5 x 5 m stone shelf. Dissolved oxygen in water ranges from 2.5–3.0 ppm up to about 22 m deep, although shallow shelves can have dissolved oxygen levels as high as 6.0–7.0 ppm in June and July. .

Inside the Devil's Hole there is a population of fish living, they are called devil hole pupae. Devil's hole pupae, also known as devil pupae, were first found in 1930 by an American ichthyologist named Joseph H. Wales. They are closely related to the Amargosa pupae and the Salt Creek pupae.

The devil hole pupa is a small fish, reaching a maximum length of 30 mm. They have different colors according to age and sex. Specifically, males are bright green and females are bright yellow. The edges of all fins are black, and the back is golden iridescent. The iridescence is particularly pronounced on the eyelids (gill lids) with a purple sheen on the back of them. The irises are blue and also have a metallic sheen.

Devil pupae live in the Devil's Pit.

Females and juveniles are more yellow than males. Females have a yellowish-brown back, and the margins of the pectoral and caudal fins are yellow, not black. However, the dorsal fin has a black border like the males. Females' brains are metallic green, and their eyes are metallic green. Juveniles have the same overall coloration as the females, although they have a translucent vertical bar on the sides. This fish has no pelvic fins. Its dorsal fin has twelve rays, while each pectoral fin has seventeen rays. The caudal fin is convex and has twenty-eight rays, curved outward at the edge. Its lateral band (the number of scales from the posterior tip of the tip to the tip of the tail) is 27 scales. The scales are serrated, or toothed, at the outer edge.

The diet of the devil pupae changes year-round, feeding on beetles, snails, algae, and freshwater crustaceans. Consumption of different food sources varies with the seasons, although inorganic granules have a high frequency in their stomachs. The scientists suggest that the inorganic granules are thought to be incidentally consumed as a result of the fish's feeding strategy of bottom-feeding and surface food.

They breed year-round, usually in spring and autumn. The peak spawning time is from mid-February to mid-May. Female devil pupae have very low fertility. Females can only produce four or five mature ovaries per breeding season. Mature ovaries account for 10-20% of the total number of ovaries produced.

Close-up of demon nymphs at Devil's Hole.

In each spawning, an adult female lays only one egg, which allows only 1 male to swim next to her. After it lays eggs, the male will fertilize it immediately. The eggs of the devil pupae are only 1 mm in diameter. Eggs also have a very low survival rate. Devil pupae can live from 10-14 months. They are often eaten by the diving beetle Neoclypeodytes cinctellus. Dive beetles eat eggs and their young. Dive beetles have only recently become part of the ecosystem and were first recorded at Devil's Hole in 1999 or 2000.

Devil's Hole has a depth of more than 130 m and the devil pupae live at a depth of 24 m. According to research by scientists, the devil pupae have lived in the Devil's Pit since about 60,000 years ago. It is said that Devil's Hole was formed 500,000 years ago. As for the cause of Devil's Hole, experts surmise that it is an earthquake. As for how the demon pupae invaded the Devil's Hole, scientists theorize they came through underground waters.

Facing the danger of extinction

Since the end of 1940, hydrologist Carl Leavitt Hubbs has begun to advocate for legal protection of the pupae in Devil's Hole. In 1967, the devil hole pupa was officially listed as an endangered species. It became one of the first species to be protected under the Endangered Species Act.

The reason is due to a large number of wells drilled in the area near the Devil's Hole. This resulted in a sharp decline in the numbers of Devilhole pupae in the 1970s due to rapid groundwater withdrawal and limited reproductive capacity. After the groundwater level increased, the number of individuals recovered again but suddenly decreased in 1995. The cause of this second decline was confirmed by scientists to be inbreeding. , algae and microbial populations are altered or due to changes in sediments.

A water level gauge is located at Devil's Hole to monitor fluctuations in the habitat of the devil pupae.

Besides the indirect threats of groundwater depletion, human actions can also affect pupae in other ways. For example, a flash flood in 2004 swept scientific monitoring equipment into Devil's Hole, causing the deaths of an estimated 80 demon pupae. As of 2014, the devil hole pupae are classified as critically endangered by IUCN (International Union for Conservation of Nature). In the state of Nevada, the devil hole nymph is considered a protected endangered species.

In April 2016, three drunken men broke into the protected area of ​​Devil's Hole, destroyed scientific equipment and waded onto the shallow shelf, smashing the eggs and larvae of pupae, as well as fish larvae. vomit into the water. This has reduced the number of devil pupae to only 37. After the vandalism took place, the US National Park Service added barbed wire to the fence that had been erected earlier and installed additional surveillance cameras.

From Crisis to Hope

In addition, the scientists added, the Guerrero - Oaxaca earthquakes in 2012, the Gulf of Alaska earthquake in 2018 and the Ridgecrest earthquake in 2019 caused seismic waves in Devil's Hole, possibly resulting in reproductive disruption of the devil pupae.

The replica of Devil's Pit was built for the purpose of preserving the demon pupae.

American scientists have made every effort to preserve devil hole pupae. They have moved them to other, safer places, but most have failed. In early 2010, they created a replica of the Devil's Hole analogue to preserve the fish at the Ash Meadows Fish Conservancy (AMFCF).

Millions of dollars have been spent to preserve the devil hole pupae, which is estimated to have cost 4.5 million USD (more than 90 billion VND). And this has caused a great controversy due to the high cost. Fortunately, the efforts of scientists have paid off, as of April 2022, the number of devil hole pupae at Devil's Hole has increased to 175 individuals.