The influence of depth and velocity on age-0 Scaphirhynchus sturgeon prey consumption: Implications for aquatic habitat restoration

Abstract

After the pallid sturgeon ( Scaphirhynchus albus ) was listed as endangered in 1990, a variety of management actions focusing on early life history needs have been implemented to aid species recovery. Given the scarcity of age-0 pallid sturgeon, managers and scientists have relied on sympatric congeners to evaluate the effectiveness of management actions in the short term; however, increased understanding of habitat requirements for age-0 Scaphirhynchus sturgeon is still needed to appropriately focus management efforts. Recently, a lack of food-producing and foraging habitats were proposed as potential limiting factors for pallid sturgeon, and the purpose of this study was to evaluate the current definition of these habitats at multiple spatial scales using data from age-0 Scaphirhynchus sturgeon (shovelnose sturgeon [ Scaphirhynchus platyrhynchus ] or hybrid [shovelnose sturgeon x pallid sturgeon]). Results showed the water depths and velocities that currently define age-0 pallid sturgeon foraging habitat had little effect on age-0 Scaphirhynchus sturgeon prey consumption. Similar results occurred when evaluating the relationship between prey consumption and food-producing habitat present 10, 20, and 30 days before capture. Assuming that individuals captured during this study were a valid surrogate, these results suggest that increasing foraging and food-producing habitat as defined by the current depth and velocity criteria is unlikely to result in the desired benefits of increased growth and survival of age-0 pallid sturgeon.