Tale of Fish Sperm and Factors Affecting Sperm Motility: A Review

Motility is an important function of the male gamete, which allows sperm to actively reach and penetrate the female gamete in organisms with internal and external fertilization. Sexual activity of some fish is generally seasonal and fertilization is external. Sperm, once differentiated in the gonad, remain there completely quiescent until they are released into the external medium, which is either freshwater or sea water. Various parameters such as ion concentrations (K+, Na+, Ca2+), osmotic pressure, pH, and temperature affect motility. In the present paper, we review the roles of these factors on sperm motility in the teleosts. Studying the effects of these factors on teleost sperm can help establish good activation and/or immobilizing media for improving either artificial fertilization or cryopreservation.