Chapter 19 The Ecology of Lifetime Growth in Percid Fishes Michael D. Rennie and Paul A. Venturelli Abstract The factors responsible for the lifetime growth patterns of percids in natural populations can provide meaningful insights for culture operations. Here, we present a summary of a number of well-studied factors and review the current state of knowledge. We illustrate an informative approach to describe lifetime growth of percid species by applying a biphasic growth model to European perch and pikeperch populations, and discuss life-history constraints considering biphasic growth. An evaluation of proposed hypotheses for proximate mechanisms of female- biased sexual size dimorphism in percids is presented, indicating that reduced feed- ing in males is the most parsimonious explanation given the current evidence. Growth rates in percids are strongly temperature-dependent, and show strong evi- dence of countergradient growth. Percids also show significant density-dependent growth, demonstrating twofold variation in individual growth rates. Predation, food availability and prey particle size can also affect the efficiency of percid growth. Parasitism and disease in percids are not as well studied as other factors reviewed here within an ecological context, but the reported effects on percid growth vary from negative to neutral to positive. Our review of drivers of natural variation in percid growth will assist culture operators with regards to broodstock selection, husbandry and maintenance of cultured percids. Keywords Percids • Growth • Broodstock selection • Sex dimorphism • Husbandry M.D. Rennie (*) Department of Biology, Lakehead University, 955 Oliver Road, P7B 5E1 Thunder Bay, ON, Canada e-mail:
[email protected] P.A. Venturelli Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota Twin Cities, 135 Skok Hall, 2003 Upper Buford Circle, 55108 St.