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Abstract
Crappies Pomoxis spp. are popular sport fishes but often fail to achieve sizes that are acceptable to anglers. While many factors may contribute to episodes of suboptimal growth in crappies, insufficient densities of prey fish and high summer water temperatures (>27°C) have been considered to be key underlying causes. We examined the influences of prey fish size, prey availability, and water temperature on the consumption and growth of white crappies P. annularis (ages 1–3) in three Missouri reservoirs over five successive years. Monthly growth rates were estimated using aging analyses, while consumption was estimated using a bioenergetics model. All age-groups grew fastest in the reservoir that was warmest but in which prey fish availability was the highest. Diet analyses coupled with bioenergetics modeling suggested that white crappies were able to maintain positive growth rates at temperatures exceeding 27°C by maximizing consumption rates when adequate prey fish resources were available. When sufficient prey fish resources were unavailable, white crappies fed on invertebrates and often ceased growing or lost weight, even during periods with suitable water temperatures. Our study documents the importance of adequate prey fish resources for maintaining positive growth rates of white crappies, especially during periods of adverse temperature conditions.
Received April 21, 2011; accepted December 13, 2011
ACKNOWLEDGMENTS
We thank Mike Colvin for assisting with project development and fieldwork. We also thank Dean Nicks, Earl Buckner, Rachel Wright, Steffanie Abel, Karen Brickey, Jamey Decoske, and numerous seasonal employees for their assistance with field and laboratory work. Anonymous reviewers’ comments on previous drafts improved the manuscript. This study was partially funded through Federal Aid in Sport Fish Restoration Project F-1-R (Study I-38) to the Missouri Department of Conservation.