Factors Affecting Survival of Age-0 SaugeyeStizostedion vitreum×S. canadenseStocked in Ohio Reservoirs

Abstract

-To explain variable stocking success of juvenile saugeye Stizostedion vitreum females × S. canadense males, we quantified survival of saugeyes in response to transport conditions, predation mortality, and prey resources at stocking in four Ohio reservoirs (162–1,145 ha) in 1991. May through October survival was 0.8–11.5%. We assessed stresses associated with transportation and handling by holding fish in small enclosures 5–10 d poststocking. Enclosure mortality varied greatly (18.9–63.5%), and because enclosures inadequately mimicked the reservoir environment, transportation and handling mortality were likely overestimated. Mortality resulting from resident piscivores was calculated via population estimates and poststocking sampling. Predation on age-0 saugeyes was minimal during poststocking sampling, ranging from 0 to 28.3% of the stocked population. Saugeye survival was statistically unrelated to zooplankton or ichthyoplankton (i.e., larval gizzard shad Dorosoma cepedianum) densities, although both ichthyoplankton density at stocking and saugeye growth showed positive trends with saugeye survival. Ichthyoplankton availability likely influences growth and survival of saugeyes; therefore, saugeye stocking should coincide with peak ichthyoplankton densities.