Factors related to growth and survival of fry- and fingerling-stocked saugeye

In reservoirs systems where natural reproduction is limited, sportfish populations are maintained by stocking programs.  In the Ohio Division of Wildlife’s over 25-year history of stocking saugeye (female walleye Sander vitreus X male sauger S. canadensis) fingerlings (TL=35 mm), survival and growth has been highly variable, while raising fish to the fingerling stage puts a substantial strain on the hatchery system.  We are assessing the feasibility of stocking fry (TL=6 mm), a practice that would reduce hatchery strain and free up time for other fisheries.  We stocked four reservoirs with fry (1000/acre) and four with fingerlings (250/acre) during 2008 and 2009.  Throughout the summer, we sampled prey availability (zooplankton and ichthyoplankton) and abiotic conditions. In the fall, we assessed growth and survival of stocked saugeye.  During both years, survival of fingerling-stocked saugeye was variable (5-317 CPH).  During 2008, survival of fry was poor (0-7 CPH), but during 2009, survival in two of four reservoirs was average to excellent (23 and 117 CPH).  Here, we use results from weekly sampling to explain variation in fall survival and growth of saugeye stocked at two different sizes, with ultimate goals of understanding saugeye recruitment and contributing to design of stocking programs.