Effects of Transport Duration and Water Quality on Age‐0 Walleye Stress and Survival

Age‐0 Walleye Sander vitreus are stocked to achieve several management objectives. However, stocked Walleye are exposed to numerous handling‐ and transport‐related stressors that can negatively influence disease resistance, survival, year‐class strength, and fisheries management objectives. The objective of this study was to evaluate relationships between Walleye transport duration with changes in water chemistry, whole‐blood glucose and plasma cortisol concentrations, and short‐term (48‐h) mortality. Walleye were transported between 3.5 and 6.0 h and stocked into holding cages located at one of seven sites. Water quality and stress (via whole‐blood glucose and plasma cortisol) and mortality were evaluated prior to, during, and at 0, 2, 24, and 48 h posttransportation. During transport, water temperatures generally decreased, while carbon dioxide concentrations fluctuated between 2.7 and 22.5 mg/L. Walleye whole‐blood glucose and plasma cortisol concentrations varied by site and time since transport. Changes in carbon dioxide concentrations were associated with changes in whole‐blood glucose concentrations. However, cumulative survival rates and plasma cortisol concentrations were not associated with water quality or transportation duration. Understanding Walleye tolerance to transportation‐induced stress has the potential to enhance stocking programs by providing the opportunity for managers to make informed transport decisions.