Walleye Egg Survival Was Unaffected by Four Semen Inclusion Techniques during Artificial Fertilization

Abstract

Improving the percent hatch during artificial spawning of walleye (Sander vitreus) could save agencies substantial resources. Semen inclusion techniques used to artificially fertilize walleye eggs may have a subsequent influence on the percent hatch. We compared walleye egg survival to the early embryo stage across four semen inclusion techniques used during fertilization to determine if one or more of the techniques would result in a higher percent hatch. Six mL of freshly collected (within 2 h) semen was presented to common pools of walleye eggs separated into 250 mL lots by either 1) pouring semen on top of the eggs before sperm activation, 2) placing 3 mL of semen below and above the eggs before sperm activation, 3) pouring 3 mL of semen on top of the eggs, activating sperm, and adding the remaining 3 mL of semen after 30 s, or 4) activating the sperm by adding semen to 1 L of water, mixing and pouring the solution on the eggs within 3 s. All treatments received 1 L of filtered lake water for sperm activation and fertilization. Mean egg survival was similar ranging from 49.5% to 56.7% among the four techniques and was not significantly different across methods. These results suggest that any of the semen inclusion techniques will likely provide a similar percent hatch for walleye eggs when 250 mL of eggs, 6 mL of semen, and 1 L of water are used during fertilization.