A dramatic warming trend, along with the correct photoperiod, allowed DNR staff to capture more than 3,100 adult female walleyes in a short amount of time at Clear, Rathbun, and Storm lakes.
Rathbun and Storm lakes began netting operations on April 6, while Clear Lake started gill netting for walleyes on April 9. The last night of netting for these three locations was April 11, but the spawning of fish continued as “green” females ripened in the hatchery.
“The 2023 season for collecting walleye adults for spawning in hatcheries was one for the ages,” said Jay Rudacille, DNR Warm and Coolwater Fish Culture Supervisor. “Mother Nature provided incredible weather for a fast and furious spawning season.”
Along with some walleye adults that stay at the hatchery all year long, netting crews collected enough walleyes to produce 763 quarts at Rathbun Fish Hatchery. Crews at Storm Lake spawned enough females to produce 631 quarts of walleye eggs, while efforts at Clear Lake produced 356 quarts of eggs. The Clear and Storm Lake satellite hatcheries transferred their eggs to the Rathbun and Spirit Lake Fish hatcheries to be incubated and hatched.
By April 13, Storm Lake and Clear Lake stations had already provided over 85 percent of the walleye eggs needed to fill the Spirit Lake Hatchery. Ice did not go off of Big Spirit and East Okoboji lakes until April 12-13. Because of the eggs provided by the satellite hatcheries, only local teams needed to net one day to collect enough muskellunge and walleye broodstock to meet egg quotas for both species. Out of town crews were not called in to assist this season. Hatchery staff believe this is the first time that the satellite stations have provided enough eggs to nearly meet quotas prior to staff netting the local lakes.
“It is hard to fathom that we could nearly reach our egg goal with only having to collect a minimal number of fish from East Okoboji or Spirit lakes, which have been reliable and significant contributors to walleye fry (newly hatched fish) production for many, many years,” said Rudacille.
“Our goal was to collect 1,880 quarts of walleye eggs to produce over 162 million walleye fry that we can stock in Iowa lakes or raise to a larger size in hatcheries before being released,” Rudacille explains. “In total, 1,891 quarts of walleye eggs are being incubated.”
DNR staff had one of the best walleye collection seasons in more than 15 years at Rathbun Lake. “Our walleye population has seen a great resurgence in recent years,” stated Mark Flammang, district fisheries biologist at Rathbun Lake. “Abundant 17- to 28-inch walleyes allowed us to capture more than 1,300 fish (627 females) in just six nights.”
It is typically difficult to catch big fish and lots of them. “We collected an abundance of walleyes with excellent size at Storm Lake this year,” said Ben Wallace, district fisheries biologist. “Storm Lake's walleye population is stellar right now and will likely remain that way for some time with the protection of the slot limit. If we can get good environmental conditions again in 2024, we should see a repeat next year.”
Three nights of walleye netting at Clear Lake produced its best year since 2015. “We collected 740 female walleye that produced just short of 356 quarts of walleye eggs,” said Scott Grummer, Clear Lake fisheries management biologist. ”There are several strong year-classes of walleye in the Clear Lake population. The outlook looks great for future hatchery operations and angling opportunities at Clear Lake.”
Iowa is one of the top producers of walleye fry in the United States, surpassed only by Minnesota in annual production. Hatchery staff will keep a watchful eye over the eggs during the 12-21 day incubation period until they hatch. Walleye fry will be stocked into 31 public bodies of water and 13 watershed rearing ponds. While the majority of Walleyes are stocked as fry, some are cultured in Iowa DNR hatcheries and stocked at different sizes. More than 1.6 million two-inch Walleyes are expected to be stocked into lakes, rivers, and streams across the state this summer. Larger 6- 9-inch fingerlings (more than 320,000) will be stocked in lakes later this fall.
With little natural reproduction in most Iowa lakes and rivers, Iowa’s Walleye populations rely heavily upon stockings. Walleyes are stocked throughout Iowa into natural lakes, interior rivers, flood control reservoirs and selected larger man-made lakes.
While the sole focus at Rathbun Fish Hatchery in the spring is collecting and producing walleyes, crews at Spirit Lake collect three species of coolwater fish: muskellunge, northern pike and walleyes. DNR personnel collected 257 northern pike that produced more than 2.4 million northern pike fry. A total of 141 Muskellunge were collected, which are currently being held in the hatchery waiting to be spawned.