Pupfish, desert

Cyprinodon macularius

phylum: Chordata

class: Osteichthyes

order: Cyprinodontiformes

family: Cyprinodontidae

status: Endangered, ESA

range: Mexico, USA (California)

Description and biology

The desert pupfish is one of at least 35 species and sub-species of pupfish. Most are threatened with extinction. The desert pupfish is small, ranging in size from 0.8 inch (2 centimeters) to 3 inches (7.6 centimeters) long. It is mainly silver in color with six to nine dark bands on its sides. This pupfish has a short, scaled head with an upturned mouth.

The desert pupfish feeds primarily on brown and green algae. It becomes dormant during cold winter months, burrowing in mud at the bottom of its water habitat. When the weather and the water warms, the fish is active again and begins to mate. Breeding males turn iridescent blue in color and fight each other over the right to mate with receptive females. After having mated, females begin spawning (laying eggs) at the end of February. The males protect the eggs until they hatch three days later. Spawning continues throughout the summer.

The average life span of a desert pupfish is six to nine months, although some survive more than one year. Many die when intense summer heat dries up their streams and pools.

Habitat and current distribution

The desert pupfish inhabits the shallow waters of desert pools, marshes, streams, and springs below 5,000 feet (1,524 meters) in elevation. It can tolerate very warm and very salty waters. The fish inhabits only scattered areas in southern California and northwestern Mexico. Biologists (people who study living organisms) have no estimates of the desert pupfish's total population.

History and conservation measures

The desert pupfish was once common in the Sonoran and Mojave Deserts of southern California, southern Arizona, and northwestern Mexico. Only three natural populations remain in California. In Mexico, natural populations survive in four locations. All natural populations of the fish were deemed extinct in Arizona in 1996. Efforts are underway to reintroduce the desert pupfish to various areas in Arizona.

The desert pupfish population has declined because human populations have increased in its range, turning desert areas into communities. As a result, the fish's water habitat has become polluted or has been drained. The pupfish has also been threatened by introduced predators and competitors such as mosquito fish, crayfish, bullfrogs, and snails.

The Dexter National Fish Hatchery and Technology Center in Dexter, New Mexico, maintains a population of desert pupfish.