TY - JOUR
T1 - Piscivory in juvenile walleyes
T2 - Relative importance of prey species, timing of spawning of prey fish, and density on growth and survival
AU - Kolar, Cynthia S.
AU - Wahl, David H.
AU - Hooe, Michael L.
N1 - Funding Information:
We thank S. Krueger of the Jake Wolf Memorial Fish Hatchery, Illinois Department of Natural Resources (IDNR), for providing walleyes. S. Stuewe, D. Austen, and L. Dunham coordinated activities with the IDNR. P. Hays and J. Fossum assisted with field work and laboratory analysis for the pond experiments. We also thank the personnel of the Kaskaskia Biological Station, especially L. Einfalt, for technical assistance. Special thanks to D. M. Lodge for patiently supporting C.S.K. while finishing this paper. This manuscript was improved with the thoughtful comments of three anonymous reviewers. This study was supported in part by the IDNR through Federal Aid in Sport Fish Restoration Project F-118-R, and a Clare Boothe Luce Memorial Fellowship (to C.S.K.) at the University of Notre Dame.
PY - 2003/7
Y1 - 2003/7
N2 - We examined the effect of the timing of spawning by prey fish and the species of prey fish on the growth and survival of juvenile walleye Stizostedion vitreum. We expected that age-0 walleyes would grow more in ponds when stocked about the same time as the spawning of gizzard shad Dorosoma cepedianum than when stocked about 6 weeks after spawning. We found, however, that the timing of larval gizzard shad presence did not affect walleye growth or survival. Also contrary to our expectations, walleyes from ponds with bluegill Lepomis macrochirus grew more (by 9% in total length and 38% in mass) than those from ponds with gizzard shad. However, the density of gizzard shad was lower than that of bluegills, particularly after the first few weeks of the experiment. Bluegills remained within the gape limits of walleyes throughout the experiment, whereas gizzard shad outgrew their vulnerability to predation. Late-spawned gizzard shad remained vulnerable to walleye predation only slightly longer than did those from early spawned ponds. The survival of age-0 walleyes was unaffected by water temperature, the timing of spawning by prey fish, prey species, or density. Our results suggest that even though walleyes typically grow faster in systems with gizzard shad as prey than in those with bluegills, juvenile walleyes can still grow well in bluegill-dominated systems. In some systems, high densities of a less beneficial prey (e.g., abundant bluegills rather than less abundant gizzard shad) may overcome the growth differences of juvenile walleyes that would be expected based on the differences in prey species alone. A wide variation in individual walleye growth in our ponds, even within prey treatments, indicated the complexity of interactions among the factors affecting juvenile walleye growth.
AB - We examined the effect of the timing of spawning by prey fish and the species of prey fish on the growth and survival of juvenile walleye Stizostedion vitreum. We expected that age-0 walleyes would grow more in ponds when stocked about the same time as the spawning of gizzard shad Dorosoma cepedianum than when stocked about 6 weeks after spawning. We found, however, that the timing of larval gizzard shad presence did not affect walleye growth or survival. Also contrary to our expectations, walleyes from ponds with bluegill Lepomis macrochirus grew more (by 9% in total length and 38% in mass) than those from ponds with gizzard shad. However, the density of gizzard shad was lower than that of bluegills, particularly after the first few weeks of the experiment. Bluegills remained within the gape limits of walleyes throughout the experiment, whereas gizzard shad outgrew their vulnerability to predation. Late-spawned gizzard shad remained vulnerable to walleye predation only slightly longer than did those from early spawned ponds. The survival of age-0 walleyes was unaffected by water temperature, the timing of spawning by prey fish, prey species, or density. Our results suggest that even though walleyes typically grow faster in systems with gizzard shad as prey than in those with bluegills, juvenile walleyes can still grow well in bluegill-dominated systems. In some systems, high densities of a less beneficial prey (e.g., abundant bluegills rather than less abundant gizzard shad) may overcome the growth differences of juvenile walleyes that would be expected based on the differences in prey species alone. A wide variation in individual walleye growth in our ponds, even within prey treatments, indicated the complexity of interactions among the factors affecting juvenile walleye growth.
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U2 - 10.1577/T99-068
DO - 10.1577/T99-068
M3 - Article
AN - SCOPUS:0042814961
SN - 0002-8487
VL - 132
SP - 679
EP - 690
JO - Transactions of the American Fisheries Society
JF - Transactions of the American Fisheries Society
IS - 4
ER -