Walleye inland lake habitat: considerations for successful natural recruitment and stocking in North Central North America

Raabe JK, VanDeHey JA, Zentner DL, Cross TK, Sass GG. 2019. Walleye inland lake habitat: considerations for successful natural recruitment and stocking in North Central North America. Lake Reserve Manage. 36:335-359. Walleye (Sander vitreus) occur naturally or through extensive introductions in many inland lakes (i.e., non-Laurentian Great Lakes) throughout North Central North America. Persistence of walleye in these systems is influenced by factors including habitat, species interactions, exploitation, and stocking. Managers have expressed concerns about recent declining walleye recruitment and abundance in many inland populations, despite various conservation efforts (e.g., stocking, regulations). Therefore, we synthesized the scientific literature to provide information on how habitat influences successful natural recruitment and stocking. Historical and more recent studies indicate walleye are most successful in coolwater, mesotrophic, intermediate-to-large (>100 ha) lakes and that they spawn close to shore, in shallow water, and predominately over gravel and cobble substrates. Recent studies suggest that age-0 recruitment bottlenecks are likely occurring between hatching and midsummer. Relatedly, survival of stocked walleye tends to be higher for large fingerlings over fry or small fingerlings. Modeling studies indicate walleye declines may be attributed to warmer water and increasing water clarity, especially in smaller lakes or those with higher Centrarchidae or northern pike (Esox lucius) abundance. Important future walleye research includes connecting spawning habitat quality and quantity with hatching and recruitment success and continued evaluation of influential factors in the first year and later life stages. Management should focus on identifying and protecting high quality lakes and important habitats (e.g., spawning), along with understanding habitat and biological factors to determine whether walleye populations can be improved (e.g., habitat projects, stocking, regulations) or in some cases not managed for altogether (e.g., too warm).