Manipulation of fertilization procedures to improve hatchery walleye egg fertility and survival

摘要

The purpose of this investigation was to determine the effect of egg depth and the timing of semen presentation on the egg survival of walleye Stizostedion vitreum and to alter these procedures to improve egg fertility and subsequent Survival and hatch. Tests were conducted evaluating egg depths of 4, 7. and 10 mm and one to three semen additions during the first minute of fertilization. The findings indicated that an egg depth of 4 mm resulted in significantly more fertile eggs (86%) than depths of 7 mm (77%) and 10 mm (65%) and that a 7-mm egg depth will yield significantly more fertile eggs than a 10-mm depth. Tests using the multiple addition of semen (extended 2: 1) to 473 mL of eggs at a depth of 4 mm resulted in the highest fertility rate of 83% when 3.0 mL of semen was added initially and then 30 s and 60 s later, compared with a 79% fertility rate for a single, 9.0-mL addition (P < 0.05). Using an egg depth of 12 rum and 9.0 mL of extended semen resulted in a fertility rate of 70%.