Since 1997, as part of the state’s lake sturgeon restoration effort – and to increase their survival rate – the Wisconsin Department of Natural Resources (WDNR) started collecting the sturgeons’ eggs below Alliant Energy’s Kilbourn Dam in Wisconsin Dells. Every year, when the river’s water temperature reaches the ideal spawning temperature of about 55 degrees – typically sometime between mid-April and early May – Kilbourn Dam employees help position large 900-gallon water tanks on the dam platform, which remain in place for several days.
Typically sometime in April, WDNR personnel gather up to two or three dozen sturgeon from the river just below the dam and place them in the water tanks. The gathered sturgeon remain in the tanks for three days. Eggs are taken from the females and sperm from the males, and both were combined in the same tank for fertilization.
Once the 100,000 to 300,000 gathered eggs are fertilized, the lake sturgeon are placed back in the Wisconsin River, with some being tagged to track their future movement and progress. The eggs are then taken by WDNR staff to the State Fish Hatchery in Wild Rose, Wis. The fish hatchery has a dedicated sturgeon growing area for the lake sturgeon eggs. The eggs typically hatch in around eight days. Around September, the young sturgeon will be released into the Wisconsin River with the hope that they will reproduce in about 25 years.
Lake sturgeon are living dinosaurs
Lake sturgeon are an ancient, mammoth fish species sometimes referred to as “living fossils” or the “living dinosaurs” of the fish world. These leathery, torpedo-shaped giants are bony-plated bottom–feeders. They typically grow to be three to five feet in length and can reach up to 80 pounds, although some fish have been found to be up to 7 feet and 200 pounds.
The fish mature between the ages of 15 and 20 years and spawn every four to six years throughout their 50 to 100 year lifespan. Due to their slow reproductive cycle, lake sturgeon are especially vulnerable to overfishing, pollution and habitat degradation. As a result, their numbers have been greatly reduced over the past century, and the lake sturgeon has been designated as a “species of concern” in Wisconsin. "Species of concern" refers to those species that might be in need of concentrated conservation actions.
Watch a WDNR video on the egg collection process.