Deployment of DIDSON in the Lower Missouri River to Examine Sturgeon Behavior

The U.S. Geological Survey Columbia Environmental Research Center in collaboration with the Nebraska Game and Parks Commission and the U.S. Army Corps of Engineers—Missouri River Integrated Science Program are engaged in a comprehensive program of research to improve the understanding of the ecological requirements and reproductive ecology of the critically endangered pallid sturgeon (Scaphirhynchus albus) in the Lower Missouri River.  The research integrates metrics of reproductive readiness with movement and habitat-use data collected using telemetry, observations of behavior using DIDSON imagery, and habitat assessments.  Dual Frequency Identification Sonar (DIDSON) is a high-frequency sonar system capable of producing high-resolution, underwater digital video imagery in highly turbid waters.  The incorporation of DIDSON imagery with telemetry tracking of tagged pallid sturgeon allows researchers to precisely document the behavior of sturgeon, identify what habitat features are important to sturgeon, and determine how sturgeon use habitat at a very fine scale.  DIDSON imagery collected in the Lower Missouri River reveals the intimate association of pallid sturgeon with flow and bedforms.  Pallid sturgeon are benthically oriented and swim just above the substrate, utilizing bedforms and bedform hydraulics to maintain position, feed and move.  Adequately characterizing the relationship of sturgeon to bedforms may be critical to evaluating the suitability of habitat for sturgeon.  Sturgeon aggregations have been described in over-wintering habitats, tributary confluences, and at spawning sites.  Descriptions of behavior and fish distribution using DIDSON imagery at these sites provide valuable insight into the biology, ecology and habitat requirements of the species.