Out-of-season spawning of mountain trout (Salmo macrostigma Duméril, 1858) through artificial photoperiod manipulation
Makaleler > Tam Makale · 2017
Yazarlar: İsa Şen, Ferit Rad
Ege Journal of Fisheries and Aquatic Sciences, Uluslararası, 2017, cilt 34, ss 219-226
DOI: 10.12714/egejfas.2017.34.2.14
Özet
The effects of artificial photoperiod manipulation on spawning time and hatchery success of 3+ old mountain trout (Salmo macrostigma) broodstock were investigated.Broodstock fish in the photoperiod group were exposed to constant long days (18L:6D), from February 1st until May 31 st , 2013 and then to constant short days (8L:16D) starting from June 1 st , 2013.The fish in the control group were exposed to natural light-dark regimes.Out-of-season milt was observed in males starting from August 15th.Out-of-season spawning of females started in August 30th and reached its peak level in September 13th.Mean values of absolute fecundity, relative fecundity, and egg size were found to be 1242.48±382.55 eggs/fish, 1148.76±336.91 eggs/kg and 4.14±0.19mm respectively.Mean fertilization, eyeing, and hatching rates of out-of-season eggs were determined as 56.77%, 20.81%, and 11.95% respectively.Regardless of the fact that the mean fecundity of females in the photoperiod group and hatching success (egg diameter, fertilization, eyeing, and hatching rates) of out-of-season eggs were lower than those in the control group, the overall results demonstrate that that regulating spawning time and out-of-season spawning of mountain trout by the use of artificial photoperiod is possible.