The effects of photothermal manipulations on the artificial reproduction of female Barbus barbus (L.) (age 6+, 0.3–0.8 kg body weight) were studied under controlled conditions. The experiment was preceded by a 3-month period of wintering (Light/Dark hourly regime 9L : 15D–13L : 11D; temperature 8–12°C). The experiment commenced when the photoperiod was changed promptly from 11L : 13D to 14L : 10D. As the experiment progressed, the photoperiod gradually changed to 16L : 8D. After 50 days of photostimulation, water temperature was increased from 12 to 17°C within 24 h, and stabilized for the next 14 or 22 days. When photothermal stimulation was completed (65 or 73 days, respectively), fish were treated with mGnRH-based ovulating agent Ovopel. The ovulation rate amounted to 33% and 22%, respectively for the shorter and longer stimulation time (difference insignificant at P ≤ 0.05). Longer photothermal stimulation resulted in lower variability of latency time, higher relative weight of stripped eggs, and higher relative working fecundity. The undesirable effect was the triggering of oocyte resorption in 11% of females.

artificial reproduction, barbel, Barbus barbus, photoperiod, temperature, stimulation