Effects of photoperiod on gestation period and sex fixing in swordtail (Xiphopharus helleri)

Abstract

Four different photoperiod (included the control tank or ambient condition tank) were tested on gestation period in female swordtails and sex fixing on the larvae, tank A were the ambient conditioned tank, which also acted as controlled tank; tank B were conditioned with 12 hour of light and 12 hour of darkness (12L: 12D); tank C were conditioned with 24 hour of light (24L: OD) while tank D were conditioned with 24 hour of darkness (OL: 24D). Result of the effect of photoperiod on gestation indicates that the ambient conditioned fishes shown the shortest gestation period compare to others, its average gestation period was 30 days. For the 1·2L: 12D conditioned fishes, its average gestation period was 32 days, follow by the 24L:OD conditioned fishes where its average gestation period was 33 days. The longest average gestation period was the OL: 24D conditioned fishes, which was 35 days. From the One-Way ANOVA statistical analysis, there were differences between the effects of photoperiods on gestation period in swordtail.