Age‐0 sturgeon and shallow water: A local‐ and reach‐scale assessment

Despite the hypothesized benefits to age-0 Scaphirhynchus sturgeon, the role that slow, shallow water plays during early life history remains uncertain. Although several studies have reported the depths and velocities observed at age-0 sturgeon capture sites, conditions at larger spatial scales beyond the immediate capture location may also be important. Therefore, the specific objectives of this study were to (a) compare catch among large reaches (26-37km in length) that varied in the availability of water <1.5m deep and (b) identify the local habitats that best promote use by age-0 sturgeon within each reach. Results from the reach-scale analysis suggested that increased availability of water <1.5m did not yield increased age-0 sturgeon catch. At the local-scale, age-0 sturgeon were routinely captured from a wide variety of depths, velocities, and microhabitats (L-dike, wing-dike, rootless-dike, and channel sandbar); these results coupled with previous research suggest that age-0 sturgeon may not require specific depth and velocity criteria but further study is needed to test this hypothesis. Although the prevalence of water <1.5m had little effect on catch rates, this habitat may still be important to age-0 sturgeon. Additional research should investigate the potential effects of shallow water, at local and broad scales, on prey consumption and condition of age-0 sturgeon.