Survival of Three Sizes of Genetically Marked Walleyes Stocked into Two Missouri Impoundments

Abstract

Survival of genetically marked walleyes Stizostedion vitreum of three size-classes was used to determine stocking success in two Missouri impoundments that differ in age, productivity, and fish species abundance. Markers at the IDHP-1* gene locus were selected because they can be detected by nonlethal methods. Stocking rates averaged 1,223 fry, 37 small fingerlings (25–51 mm in total length, TL), and 24 advanced fingerlings (91–122 mm TL) per hectare. Zooplankton were sampled before and after fry and small fingerlings were stocked. Walleyes collected by electrofishing during the 2-year period after stocking were used to compare stocking success. General sampling of fish populations was also conducted by electrofishing during the study period. Small fingerlings exhibited greater rates of survival in both impoundments than did advanced fingerlings, and both fingerling sizes were returned at significantly higher rates than fry. Although increased survival is generally assumed for an increase in stocking size, study results and production characteristics justify stocking walleyes as small fingerlings in Missouri impoundments.