Desert Pupfish, Cyprinodon macularius
Note: This Species is currently considered to be ENDANGERED and if encountered should be handled accordingly.
Desert Pupfish, Cyprinodon macularius. Fish collected from the feeder streams of the Salton Sea, Southern California, March 2018, photographed quickly returned to its native environment unharmed.
Desert Pupfish, Cyprinodon macularius. Fish collected from the feeder streams of the Salton Sea, Southern California, March 2018, photographed quickly returned to its native environment unharmed.
Desert Pupfish, Cyprinodon macularius, Male. Fish collected from the feeder streams of the Salton Sea, Southern California, March 2018, photographed quickly returned to its native environment unharmed.
Note: In 1986 the Desert Pupfish was placed on the Federal Endangered List by the United States Department of the Interiors Fish and Wildlife Service covering the known populations in Arizona and California. The fish is included in this www site to provide education to recreational anglers in case they encounter this species in the wild and can treat the catch appropriately, i.e., immediately returning to its native environment unharmed. It is also included due the availability of quality photographs taken by one of my readership who encountered the fish in the wild and asked for my help with the identification.
The Desert Pupfish, Cyprinodon macularius, is a member of the Pupfish or Cyprinodontidae Family, and is known in Mexico as carhorrito del desierto. Globally, there are forty-nine species in the genus Cyprinodon of which twenty-nine are found in Mexico’s freshwater systems.
The Desert Pupfish has a rounded back with a thick body that is laterally compressed with rounded fins. They are sexually dimorphic with males being blight-blue in color; the females and juveniles are silvery or tan with dark vertical bars. The dorsal portions of the heads of the males become bright blue with yellow or orange tinges on the caudal peduncle and caudal fin. Their head is short and compressed with an upturned mouth equipped with tricuspid teeth.
The Desert Pupfish is non-migratory and found in shallow clear waters of desert springs, small streams, and marshes with aquatic plants and restricted flow over mud or sand substrate. They can tolerate high salinities, elevated water temperature up to 45oC (113oF), large daily water temperature changes, and low oxygen content at levels that are higher than virtually all other freshwater fish giving them a competitive advantage over non-native fish.
They reach a maximum of 7.6 cm (3.0 inches) in length with males being larger than females. They are opportunistic omnivores that forage early mornings or late evenings that consume algae, crustaceans, detritus, insect larvae, invertebrates, mosquitos, and midges. They are prolific breeders capable of generating three generations per year. Reproduction is oviparous with the males selecting and protecting the breeding location and each female producing 50 to 800 individual eggs that are immediately fertilized by the males and buried in the substrate. Their eggs are subject to cannibalism by Desert Pupfish that are not the parents and to prey by other fishes. They can reach full maturity within three months. They have the ability to bury themselves in the substrate to avoid predation. They have life spans of up to three years.
The Desert Pupfish are found in the Colorado River Delta in Sonora and the Laguna Salada Basin in Baja California at elevations below 1,524 m (5,000 feet).
The Desert Pupfish is a straight forward identification that cannot be easily confused with any other species.
From a conservation perspective the Desert Pupfish is currently considered to be VULNERABLE with populations and range declines documented to be up to 95% in recent years that are attributed to the removal of water from their habitats, steam impoundment, domestic livestock grazing, mining, road construction, pollution and the introduction of non-native species including Crayfish, Frogs, Mosquitofish and Tilapia. They relatively intolerant of competition and predation. They are very small in stature and of limited interest to most, however, they are utilized by the aquarium trade on a limited basis and are difficult to maintain. They are currently, however, a major focus of conservationists in Arizona and California.