Abundance and Growth of Young-of-Year Walleye (Stizostedion vitreum) and Sauger (S. canadense) in Pool 10, Upper Mississippi River, and at Prairie du Sac Dam, Lower Wisconsin River, 1987–1994

Abstract

ABSTRACT We estimated the relative abundance and growth of young-of-year (YOY) walleye (Stizostedion vitreum) and YOY sauger (S. canadense) based on night electroshocking each October from 1987–1994 in the upper part of Pool 10 on the upper Mississippi River and in the tailwaters of the Prairie du Sac dam on the lower Wisconsin River. Catches of each species varied substantially from year to year at each location. Strong year classes of walleye and sauger were produced at both locations in 1991 and 1994, and weak year classes were produced in 1990. In other years, relative year-class strengths were only partially concordant between species and locations. Overall, growth of YOY walleye and YOY sauger was fast at both locations, and varied less than abundance. However, annual growth fluctuations were not correlated between species or between locations. Abundance and growth of YOY walleye and YOY sauger were correlated to only a limited extent with water levels during the spring (April-May), with air tempera...