Walleye Spawning Habitat in Pool 13 of the Upper Mississippi River

Abstract

Abstract Continued development in the upper Mississippi River may pose a threat to critical fish habitats. The purpose of this study was to identify spawning habitat for walleyes Stizostedion vitreum so those areas could be afforded protection from future alterations. Radiotelemetry, egg collections, and the presence of sexually mature fish were used to identify walleye spawning sites in Pool 13 of the upper Mississippi River. Over 2,000 walleye eggs were collected in drift nets at two sites from 1983 through 1986. Substrates at spawning sites comprised sand, gravel, and cobble and included a freshwater mussel bed at one location. Water depths at spawning sites ranged from 0.6 to 6.1 m, and the current velocity ranged from 42.7 to 115.8 cm/s during 1986. Most walleye eggs were collected in April within 2 weeks of peak discharges when water temperatures were 8.3-12.2°C. Both spawning sites were adjacent to the navigation channel.