ACQUISITION, INITIATION AND MAINTENANCE OF SPERM MOTILITY IN THE SHARK, TRIAKIS-SCYLLIA

Shark sperm were immotile in the testis, hut motile in the vesicula se minalis, suggesting that motility potential is acquired in the male re productive tract. Although sperm acquired motility, they were immobile in the undiluted semen, however, motility occurred upon dilution of t he semen in electrolyte solutions, whose concentrations are the same a s seawater or uterus fluid, suggesting that exposure to these fluids a t ejaculation causes the initiation of sperm motility. Duration of spe rm motility was longer in glucose-rich uterus fluid than glucose-free media, suggesting the important role of hexose for maintaining sperm m otility in female reproductive tract.