The effect of different photoperiod on survival and morphological changes of nile tilapia (oreochromis niloticus) fry

Abstract

Long-day photoperiods are considered as an effective managerial tool in manipulating fish growth and morphology in a number of fish species. In this study, three different photoperiod regimes were exposed to Nile tilapia (Oreochromis niloticus) fry in order to determine the fish survival. Besides that, the other purpose of this study is also to investigate the effect of different photoperiods toward fish morphological changes. Fish total length, TL fish body depth, BD and deformities were accessed at three different photoperiod treatments of Tl(l2L:l2D), T2 ( l6L:8D), T3(24L:0D), and control. Growth and development of the fries increased with increasing photoperiod duration in all treatments throughout the two weeks experiment. The best performance for TL and BD was recorded in treatment with continuous light (24L:0D). No deformities was observed in all treatments conducted in this study. The highest percentage of survival rate was recorded at photo period T3(24L:0D) and the lowest was at TI ( I 2L: l 2D). The results from this study indicate that extended light increases the growth of Nile tilapia fry because during this stage, the fish are more sensitive with light and also other environmental factors.