Influence of Larval Gizzard Shad (Dorosoma cepedianum) Density on Piscivory and Growth of Young-of-Year Saugeye (Stizostedion vitreum × S. canadense)

Abstract

. 1994. Influence of larval gizzard shad (Borsscama cepedianum) density on piscivsry and growth of young-of-year saugeye (Stizostedion vitreum x S. caraadense). Can. 1.Fish. Aquat. Sci. 51 : 1993Sci. 51 : -2082 Growth and survival of young-of-year saugeye (Stizostedion vitreum 9 x S. canadense 6) (stocked into Ohio reservoirs to create sport fisheries) are probably influenced by prey availability, variations in which may account for historically documented variability in stocking success. Because saugeye switch from a diet of zooplankton to fish once stocked, we sought to determine experimentally if saugeye size and available ichthyoplankton, i.e., larval gizzard shad (Borosoma cepediaraum), affected this switch and whether piscivory improved saugeye growth. In an enclosure experiment, saugeye (33.9 mm TL) immediately switched to piscivory when exposed to ichthyoplankton densities of 20 and l O~-m -~, growing faster when more gizzard shad were available. In another enclosure experiment, saugeye 30-49 mm TL consumed 14-rnm gizzard shad. In ponds (N = 4 ponds-treatment-') containing zooplankton and chironornids, we compared saugeye growth with and without larval gizzard shad and found, as in the first enclosure experiment, that piscivory improved saugeye growth. Neither saugeye size nor ichthyoplankton density influenced how quickly saugeye switched to piscivory. We conclude that managers should stock saugeye 230 mm 1-2 wk before peak ichthyoplankton densities to improve saugeye growth and survival by enhancing opportunities for exploitation of young-of-yeas gizzard shad.La croissance et la susvie de jeunes de l'annee issus du croisement entre le dor6 jaune et le dore noir (Stizostedisn vitreum B x S. canadense 8 ) (ensernences dans des reservoirs en Ohio pour la peche sportive) sont probabfement influencees par I'abondance des proies, dsnt les variations peuvent expliquer la variabilite historique du succ&s de I'ensemencement. Etant donne que ce dore hybride passe d'un regime form6 de zooplancton A un regime piscivore d&s I'ensemencernent, nous avons tent6 de determiner experimentalernent si la taifle du poisson et la presence d'ichtyoplancton, c.-a-d. la Barve de I'alose a gesier (Dorosoma cepedianum), influen~aient cette modification du regime et si le regime piscivose accelerait la croissance du dore. Dans une experience en enclos, les dor6s (LT = 33,9 mm) snt adopte immediatement un regime piscivore Borsqu'ils ont ete exposes h des densites d'ichtyoplancton de 28 et de 100-m-" et leur croissance s'est revklee plus rapide en presence d'une plus grande quantit6 d'aloses h gesier.Dans une autre experience en enclos, des dores de 30 A 49 mrn de LT ont consomm6 des alsses A gesier de 14 mm. Dans des etangs (N = 4 &tangs-traiternent-') renfermant du zooplancton et des chironomides, nous avons compare la croissance du dor6 avec et sans la presence d'aloses 2 gesier. lVous avons observe, comme dans la premi&re experience en enclos, que le regime piscivore activait %a croissance des dorks. N i la taille des dores, ni...

Enhancing Percid Stocking Success by Understanding Age-0 Piscivore-Prey Interactions in Reservoirs

“…Final zooplankton densities did differ, ranging from 14.3 Ϯ 6.7 individuals/L in enclosures with 20 larval gizzard shad to 150.4 Ϯ 29.8 individuals/L in enclosures without larval gizzard shad (one-way ANOVA, P ϭ 0.022). Mean density of those taxa commonly eaten by saugeye, cyclopoids, Daphnia, and calanoids (Fielder 1992, Stahl andStein 1994), was 41.2 Ϯ 7.9 individuals/L on day 0 and 3.2 Ϯ 1.1 individuals/L on day 13, and did not differ among treatments (one-way ANOVAs, day 0, P ϭ 0.19; day 13, P ϭ 0.72).…”

“…Specifically, we sought to extend the findings of Stahl and Stein (1994), who documented that time to piscivory did not differ between 20 and 100 larval gizzard shad/ m 3 . Hence, we tested four low-density treatments of 0, 5, 10, or 20 larval gizzard shad/m 3 .…”

“…Saugeye were transported in aerated solutions (0.5% salt) of pond water and stocked at one point in each reservoir. Transportation to all reservoirs was Ͻ2 h; transportation mortality of saugeye is generally Ͻ20% to Ohio reservoirs (Stahl and Stein 1994).…”

“…In a modeling exercise, increasing growth rates of larval bloater (Coregonus hoyi) by 0.2 mm/d increased larval survival by about 50ϫ (Luecke et al 1990). Conversion from zooplanktivorous or benthivorous feeding to piscivory greatly increases growth (largemouth bass, Aggus and Elliott 1975, Gutreuter and Anderson 1985, Olson 1996; J. E. Garvey, Aquatic Ecology Laboratory, The Ohio State University, unpublished data; Esox spp., Carline et al 1986; Stizostedion spp., Forney 1976, B. L. Johnson et al 1988, Buijse and Houthuijzen 1992, and can be regulated by prey type (Werner and Gilliam 1984), density , and size (Jackson et al 1992), or some combination of these three factors (Mittelbach 1981, Stahl andStein 1994). Timing of this diet conversion can govern summer growth potential of piscivores (DeAngelis and Coutant 1982, Werner and Gilliam 1984, Gutreuter and Anderson 1985, Adams and DeAngelis 1987, Fox 1989 and depends on spawning time of both predators and prey, and their subsequent growth rates (Olson 1996).…”

Seasonal Consumptive Demand and Prey Use by Stocked Saugeyes in Ohio Reservoirs

“…Though stocked saugeyes consume a variety of prey, predominately shads Dorosoma spp., crappies Pomoxis spp., sunfishes Lepomis spp., silver-sides Menidia spp., and yellow perch Perca flavescens (Humphreys et al 1987;Johnson et al 1988a;Leeds 1992), gizzard shad (and their larvae) are particularly important to saugeye stocking success (Stahl and Stein 1994;Donovan et al 1997). Gizzard shad thrive in the shallow (typical mean depth = 4-5 m), mesotrophic-eutrophic (typical total P = 20-60 μg/L) reservoirs found throughout Ohio and are the epitome of dense, highly variable prey fish populations (Bremigan and Stein 2001).…”