Walleye Spawning

By Conservation Technician Ryan Braun

Even though we had a pretty mild winter it seems like everyone is excited to see spring arrive. The start of the walleye spawning season is generally an indicator of nice weather to come. Walleye spawning typically starts in early to mid-April. The 2022 egg collection goal for the South Dakota Department of Game, Fish and Parks (GFP) is 95 million eggs. Last year, a goal of 200 million eggs was reached. Thus, this year’s goal is achievable. Spawning crews from several GFP fisheries offices around the state will help with the 2022 goal.

We know approximately when walleyes spawn each year, but a couple key factors determine when actual spawning occurs. These two factors are water temperature and photoperiod. Ideal water temperatures are 44-50 degrees Fahrenheit. Photoperiod is the amount of daylight in a day. As the days get longer the walleyes move from deep water to shallow water in preparation to spawn.

Trap nets set perpendicular to the shoreline are used by GFP crews to catch walleye that are ready to spawn. Each net has a 50-foot lead line that the fish will follow into a holding trap where they can’t find their way out. Once in the trap net, the fish are collected and transported in a large tank to a spawning site.

At the spawning location, male walleye are kept separate from the females. The females are sorted as green (not ready to spawn) and ripe (females ready to spawn). Eggs are squeezed out of one to two ripe females into a shallow pan, and then the milt (sperm) from two males is added to the eggs. Water is added to activate the milt, and the mixture is stirred for two minutes to ensure the eggs are fertilized. A mud mixture called diatomaceous earth is then added to the mix and everything is stirred for another two minutes. Adding the mud helps to prevent the eggs from sticking together. Eggs are then rinsed and cleaned in filtered water before being placed in boxes to be taken to the Blue Dog State Fish Hatchery.

Once the eggs arrive at the hatchery, they are placed in jars with circulating water. The incubation period for the eggs to hatch is around 21 days. When the eggs hatch, the walleye fry swim up out of the jar into a trough before swimming into a holding tank where they are netted. Young walleyes are stocked into lakes across South Dakota.

It takes time for a walleye to reach a desirable size. Walleyes typically grow to 14 inches in 3 to 4 years, commonly attain weights over 8lbs, and live to be 15 to 20 years old. Whether you want a walleye for the wall or a few just to eat, now is a good time to go fishing and enjoy the products of previous GFP walleye spawning efforts.