Manipulated Photoperiod Enhances Sperm Production and Quality in Male Gray Snapper Lutjanus griseus (Linnaeus, 1758): A Potential Approach for Tropical Aquaculture

Abstract

Photoperiod manipulation has been used as an alternative non-invasive method to stimulate sexual maturation in fish. It consists of spatial and temporal manipulation of reproductive physiology. There are few studies on the effect of photoperiod on reproduction in male fish, particularly in tropical climates. Because of this, the present study focused on inducing gonad maturation in male gray snapper (Lutjanus griseus), by manipulating of photoperiod. From the fourth week of March (12h and 30 min light), the day length was increased by 2.4 minutes per day until the maximum estimated annual day length (13h and 42 min light) was achieved. All fish exposed to the artificial photoperiod produced sperm. In addition, greater fluidity and greater sperm motility were observed, with a higher number of sperm cells per ml (5.14 million cells ± 1.64 e6) compared to fish exposed to the natural photoperiod (3.63 million cells ± 0.36 e6). Current results indicate that manipulated photoperiod can be used to lengthen the duration of sperm production in gray snappers.