Incubation of Walleye eggs in Petri dishes

ObjectiveEggs of Walleye Sander vitreus are typically incubated in upwelling jars. The relatively large number of eggs required for efficient and effective incubation in each jar, along with the difficulties in accurately quantifying egg survival to fry hatch, inhibits the replication needed for the controlled experimentation of Walleye spawning procedures and egg development. In addition, the use of production-sized incubators for experiments can be problematic because of the risks associated with potentially hazardous treatments on large numbers of eggs. This study evaluated the technique of incubating small numbers of Walleye eggs in Petri dishes.MethodsEight treatments were used: (1) 20 eggs/dish with daily water exchanges, (2) 40 eggs/dish with daily water exchanges, (3) 20 eggs/dish with every-other-day water exchanges, (4) 40 eggs/dish with every-other-day water exchanges, (5) 20 eggs/dish with every-third-day water exchanges, (6) 40 eggs/dish with every-third-day water exchanges, (7) 10 eggs/dish with no water exchanges, and (8) 20 eggs/dish with no water exchanges. At the eyed stage of egg development, water in all dishes was exchanged daily; at hatch, water was changed and hatched fry were removed twice daily.ResultMean (SE) survival to hatch was 74% (2) and was not significantly different among any of the treatments.ConclusionThese results indicate that small numbers of Walleye eggs can be successfully incubated in Petri dishes without any water changes before the eyed stage of development, making this a viable technique for use in controlled experiments. Successful incubation of Walleye eggs in Petri dishes is the groundwork for small-scale replication for use in future controlled experimentation on spawning and incubation techniques.Impact statement