Induction of Spawning in Common Carp (Cyprinus carpio) Using LHRHa ([D-Ser (tBu)6, Pro9-NEt]-LHRH) Combined with Haloperidol: Effects of Different Treatment Time and Determination of Latency Period Dependence on Temperature

A single injection of 20 mu g/kg LHRHa ([D-Ser (tBu) super(6), Pro super(9)-NEt]-LHRH) combined with 0.5 mg/kg of the dopamine receptor antagonist, Haloperidol (LHRHa+HAL) was used for induction of spawning in the common carp under routine hatchery conditions. This treatment caused successful ovulation. Latency in common carp injected with LHRHa+HAL was dependent on water temperature, and minimal latency was 14 h. When LHRHa+HAL was given at various hours of the day it resulted in identical spawning with the same latency. These results show that the predicting latency at a given temperature may provide successful hatchery management for fish farmers.