Devils Hole pupfish

The Devils Hole pupfish is a critically endangered species that inhabits only Devils Hole, a singular water-filled cavern in Nevada, USA. Discovered in 1930, this diminutive fish belongs to the pupfish family. Males exhibit a vibrant bright blue coloration, while females and juveniles display a yellow hue. Notably, they lack pelvic fins and subsist on limited food sources available in their isolated environment. They must also contend with diving beetles, their principal predators. Although the pupfish reproduce year-round, their survival rates are alarmingly low.

Devils Hole itself is a remarkable habitat, characterized by a constant temperature and low oxygen levels, posing significant challenges for the species. Unfortunately, the pupfish face numerous threats, including groundwater depletion, flash floods, earthquakes, and even acts of vandalism. Efforts to establish additional populations have largely been unsuccessful. Conservation initiatives involve creating refuges, sustaining the wild population, and constructing a replica of their habitat at conservation facilities. These endeavors have proven costly and, at times, contentious, with some questioning the rationale behind conserving the species.

Population counts are conducted biannually, revealing considerable fluctuations in numbers. The Devils Hole pupfish was added to the U.S. endangered species list in 1967 and designated as critically endangered by the International Union for Conservation of Nature (IUCN) in 2014. There is ongoing debate about the fish's taxonomy and evolutionary history, with estimates of their existence ranging from 1,000 to 60,000 years.

Both in situ (within their natural habitat) and ex situ (outside their natural habitat) conservation methods are being employed to safeguard this unique species. These efforts include removing sediment, supplementing their food supply, and establishing protected areas. Nevertheless, conservation endeavors have encountered challenges, such as hybridization and maintenance issues within refuge populations. The high costs associated with these efforts have sparked ethical debates over the value of saving the species.

Despite these obstacles, recent population surveys offer a glimmer of hope. The pupfish population once surged to around 550 individuals, with numbers increasing from a mere 35 in 2013 to 136 in 2019. The distinctive habitat and precarious status of the Devils Hole pupfish make it a focal point for conservationists and scientists dedicated to its preservation.