干旱区生态环境知识资源中心

The endangered Mohave tui chub Gila bicolor mohavensis, which occurs only in three populations in southern California, has not been previously spawned in captivity. Captive breeding of imperiled fishes can be important to conserve biodiversity and aid in native fish conservation efforts by reducing the collection of wild fish for translocations, providing individuals for experimental studies, and ensuring species survival. To spawn Mohave tui chub, we lowered water temperature to 10 degrees C, held this temperature constant for 30 d, and then warmed the tank at a rate of 1 degrees C per day to reach ambient air temperature (20-22 degrees C). We used a photoperiod of 10 h light : 14 h dark and adjusted the photoperiod to 14 h light : 10 h dark when the tank reached 15 degrees C. These photoperiod and water temperature regimes were designed to simulate Mojave Desert springtime conditions. Artificial plants were provided as spawning substrate. Three spawning events produced over 1,700 larval fish. Fish not subjected to this photoperiod and water temperature regime did not spawn. Simulation of a spring photoperiod and temperature regime was associated with successful spawning of Mohave tui chub in captivity and may be effective for spawning other endangered cyprinids with similar requirements.