Factors Influencing Year-Class Strength of Percids: A Summary and a Model of Temperature Effects

Abstract

Factors regulating year-class strength in the percid genera Stizostedion and Perca are summarized. Some index of water temperature regime correlates significantly with year-class strength of percids in many water bodies. Moderate synchrony of year-class strength is noted for walleye (Stizostedion vitreum vitreum) in several lakes in North America. A probablistic model is proposed to explain the basis of temperature dependence of year-class strength in percids, but tests of the model using Lake Erie data indicated that observed correlations between temperature and year-class strength of yellow perch (Perca flavescens) and walleye may not be the result of direct effects of the temperature regime on survivorship of early life-history phases. Key words: Percidae, year-class strength, temperature, probalistic model, early life history