Supplemental Stocking of Fingerling Walleyes in the Upper Mississippi River

Abstract

Experimental stocking of fingerling walleyes Stizostedion vitreum was initiated in 1987 to determine if the native population in Pool 14 of the upper Mississippi River could be enhanced. Fall tailwater electrofishing surveys were used to develop indices of age-0 and age-1 abundance for Pools 14 and 15 over a 5-year period. Fingerling stocking at a density of 1 1 /hectare had little or no measurable effect on a strong natural 1987 year-class. In Pool 14, stocking densities of 27 and 30/hectare enhanced the 1988 and 1989 year-classes by 46 and 39%, respectively. Downstream dispersal of stocked fingerlings into Pool 15 occurred each year, and at this location stocked walleyes constituted from 3% of the 1987 year-class to 69% of the 1989 year-class. Growth of stocked walleyes was similar to that of naturally produced fish; no significant differences were noted within each pool.