Tolerance of Incubating Walleye Eggs to Temperature Fluctuation

Abstract

Eggs of walleyes Stizostedion vitreum incubating under hatchery conditions were subjected to temperature fluctuations of −8.8, −9.3, +13.6, +20.2, or −21.1 followed by +21.1°C. We found that eye-up rates remained approximately 70% for all control and test lots. Swim-up rates were reduced from approximately 90% for the control and first three temperature variations to 42% and 13.6% for the last two temperature variations. We conclude that temperature fluctuations great enough to directly affect incubating walleye eggs are unlikely to occur in hatcheries or on natural spawning grounds.