Abstract

The reproductive cycle of Nassau Grouper (Epinephelus striatus), a large, commercially valuable predatory fish inhabiting coral reefs throughout the tropical western Atlantic, is linked to circadian rhythms and seasonal changes in the environment. Spawning occurs during full moons of December and January indicating the use of full moon as a clue to trigger reproductive behavior. Until recently, photoreceptors (rods and cones) were the only cells known to contain light-sensitive opsin protein. However, in recent studies the phototransductive protein melanopsin was found in retinal ganglion cells, which is believed to play an important role in the regulation of rodent circadian rhythms. This study investigates the presence of melanopsin in the Nassau grouper retina and seeks to demonstrate that this photoactive protein serves as a dim-light molecular switch in Nassau grouper reproduction. Studies of the Nassau grouper reproductive system at the molecular/biochemical level are needed to provide the biological foundation for making informed management decisions and insuring the conservation and protection of this economically valuable species

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