ENHANCING PERCID STOCKING SUCCESS BY UNDERSTANDING AGE-0 PISCIVORE–PREY INTERACTIONS IN RESERVOIRS

Abstract

Though young-of-year (YOY) saugeyes (Stizostedion vitreum × S. canadense) are routinely stocked in spring to create and maintain percid fisheries, their growth and survival to fall vary greatly among Ohio reservoirs, as well as among years within a reservoir. To understand the relative importance of size-dependent and size-independent mechanisms during ontogeny that underlie variable stocking success of saugeye, we quantified the role of stocking date and prey density (zooplankton and ichthyoplankton, i.e., larval gizzard shad [Dorosoma cepedianum]) in field enclosure, pond, and reservoir experiments. In 1-m3 enclosures, ichthyoplankton density (0, 5, 10, or 20 larval gizzard shad/m3) did not influence time to switch to piscivory by saugeye (all switched in <12 h); saugeye in enclosures with ichthyoplankton, regardless of density, grew faster than those without ichthyoplankton. In 0.4-ha ponds, saugeye growth and survival did not differ between ponds with zooplankton plus macrobenthic prey and ponds with ...