Natal Contribution and Movement of Gizzard Shad in Lake Sharpe, SD Evaluated Using Otolith Microchemistry

The Missouri River is the longest river in the United States, drains 1/6 of the nation, and has six mainstem reservoirs that support important sport fisheries. Side-channel embayments are rare in reservoirs, and are thought to be crucial habitat for forage and sport-fish. In South Dakota, Hipple Lake, a side-channel embayment in Lake Sharpe, is in danger of losing connectivity to the reservoir because of sedimentation.  This embayment is suspected to provide important spawning habitat for gizzard shad and various sport-fish. We collected age-0 and adult gizzard shad from Hipple Lake and several sites in Lake Sharpe and used otolith microchemistry to evaluate the contribution of Hipple Lake to the Lake Sharpe gizzard shad population. At least 26% of adult gizzard shad in Lake Sharpe (~25,000 ha) originated in Hipple Lake (178 ha). Nearly half of all gizzard shad production for the entire reservoir occurred in two embayments (Hipple Lake and La Framboise) that make up less than two percent of Lake Sharpe’s surface area. This research will guide management actions regarding maintaining connectivity between embayments and large rivers.