Evaluating the contributions and economic costs for Walleye fry and fingerling stocking in a large midwestern reservoir

Stocking is a common management practice to maintain Walleye populations where natural recruitment is low or to introduce and sustain Walleye populations outside of their native range. Walleye can be stocked at multiple lengths (e.g., fry and fingerling) and different sizes of stocked Walleye may contribute differently to Walleye year class strength, depending on the system into which they are stocked. The cost associated with stocking also varies by product. Therefore, it is important to determine the contributions from different stocked products within a region or for an individual waterbody. The objectives of our research were to 1) compare the relative contribution of and total length and body condition at the time of capture at age-0 between stocked Walleye fry and fingerlings and naturally produced individuals; and 2) estimate and compare the economic costs of Walleye fry and fingerling production relative to their contribution to the age-0 catch in Lake McConaughy during 2022 and 2023.We collected 178 and 263 age-0 Walleyes from Lake McConaughy during the summer and fall of 2022 and 2023, respectively. Fingerling-stocked Walleye contributed 2.12 times in 2022 and 2.92 times more in 2023 than fry-stocked Walleye. Production cost estimates revealed that fry cost 1.08 and 1.35 times greater than fingerlings per stocking unit in 2022 and 2023, thus fingerlings were deemed the most cost-effective product in this study. Walleye stocked as fry were significantly longer at the time of collection in 2022 and were in significantly better condition in both years compared to fingerling stocked Walleye. Our results provide valuable insights for fisheries managers by offering a case study example as well as offering a practical approach to guide effective management decisions on which stocked product is most appropriate for other systems. Overall, this research enhances the existing literature on Walleye stocking in large reservoir systems, offering practical and useful information for effective management decisions.