Yellow Perch Sperm Motility, Cryopreservation, and Viability of Resulting Larvae and Juveniles

The sperm of Yellow Perch Perca flavescens of two different age-classes, age 0 and 3, were cryopreserved using two different cryoprotectants (dimethylsulfoxide [DMSO] and methanol [MetOH]) with two freezing methods (pellet and vial). The viability and quality of the progenies obtained from fertilization with cryopreserved sperm were then examined. The motility of Walleye Sander vitreus sperm was examined following cryopreservation and ultraviolet (UV) irradiation, with the aim of using heterologous cryopreserved sperm to inseminate Yellow Perch eggs to ensure gynogenesis. The first experiment compared the motility of fresh sperm and pellet method cryopreserved sperm devoid of salmon seminal plasma. Despite the high motility of fresh sperm-75% and 100%-of males age 0 and 3, respectively, the postthaw motility of seminal plasma devoid cryopreserved sperm was 0%. The second experiment addressed the efficiency of pellet and vial freezing methods with DMSO and MetOH supplemented with salmon seminal plasma. Cryopreserved sperm was thawed and motility measured. Sperm motility was not significantly different between pellet (13.3 +/- 10.4%) and vial (10.3 +/- 12.9%) methods in the absence of sperm extender; however, sperm motility of the pellet method was further improved (20 +/- 8.7%) with the addition of sperm extender after thawing, while motility of the vial method sperm (10 +/- 7.1%) was not. Cryopreserved sperm was further evaluated based on fertilization rate and ultimate survival and growth of larvae and juveniles through 14 d posthatch. Effects of UV exposure on fresh and pellet method cryopreserved sperm following UV irradiation were also examined. The motility of control sperm cryopreserved with DMSO and MetOH, and UV-exposed sperm cryopreserved with DMSO decreased from 100% motility before cryopreservation (fresh sperm) to 75% following cryopreservation, while UV-exposed sperm cryopreserved with MetOH decreased from 100% to 50%. This experiment provides significant new data to improve the effectiveness of straightforward cryopreservation techniques for Yellow Perch.