Effects of Environmental Factors on Walleye and Sauger Recruitment in Pool 13, Upper Mississippi River

Abstract

Abstract I measured the abundance of walleyes Stizostedion vitreum and saugers S. canadense in the spring as larvae and in the fall as age 0 to determine which factors limited reproductive success in Pool 13 of the upper Mississippi River. Catches of larval walleyes and saugers in conical and rectangular drift nets during 1993–2000 were significantly higher in night samples than day samples but were similar at the surface and at the bottom. The fall abundance of age-0 walleyes and saugers in four to eight nights of sampling at fixed sites in lock and dam tailwaters during 1992–1999 was not correlated with the spring abundance of larval walleyes and saugers. However, the fall abundance of age-0 walleyes and saugers was highly correlated with the rate of water warming (°F/d) between April 15 and May 5. Age-0 walleye and sauger abundance was not correlated with river discharge during the April spawning period. Strong walleye and sauger year-classes were produced in 1992, 1994, and 1997 in Pool 13. The age-0 ...