Abstract
Sauger (Stizostedion canadense) reproduction and early life history have been studied to determine factors affecting year-class strength in Lewis and Clark Lake, a 28,000-acre reservoir on the South Dakota-Nebraska border. Sauger spawn over a rubble substrate in the Missouri River below Fort Randall Dam. Spawning is initiated at a water temperature of 43 F and is complete in approximately 2 weeks. Maximum egg survival occurs 4 ft below minimum river water level. Eggs hatch in 21 days at an average temperature of 47 F and larvae drift down the Missouri River and into Lewis and Clark Lake. The yolk sac is absorbed in 7 to 9 days and larvae feed primarily upon Cyclops. Larger size larvae feed on Daphnia and Diaptomus. Fish are a major food after sauger reach 70 to 110 mm lengths. Adult year-class strength was inversely related to water level fluctuations over the spawning grounds. Abundance of larvae was 15 times greater in 1965 when water levels fluctuated 2.67 ft/day than in 1963 when water levels fluctuated 4.44 ft/day. Apparently, year-class strength is dependent upon water level fluctuation during the incubation period and is determined before young-of-the-year enter Lewis and Clark Lake.
Published Version
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