DEVELOPMENT AND UTILIZATION OF A POPULATION-GROWTH HISTORY OF RED-LAKE WALLEYE, STIZOSTEDION-VITREUM

An environmental growth history of commercially harvested walleye, Sti zostedion vitreum, in Red Lakes, Minnesota, was constructed for the ye ars 1944-1992. This was accomplished using a linear model which was fi tted to annular scale increment measurements. Increment size was separ ated into one component due to a combination of environmental factors, an environmental growth coefficient, and one due to the age of the fi sh. Our hypothesis was that variables such as air temperature, walleye year-class strength, catch-per-unit-effort (CPUE) of walleye, and CPU E of yellow perch, Perca flavescens, affect walleye growth, and theref ore a historical series of these variables would show coherence to the series of walleye growth coefficients. Multiple regression techniques were used to test these hypotheses. Significant predictors of the gro wth of walleye after age one were average February temperature, cumula tive degree days in July, walleye year-class strength, and growth of y oung-of-the-year (YOY) walleye. We hypothesized that YOY walleye respo nd to a different set of factors than walleye after age one, thus, a s eries of YOY growth measurements would show coherence to a different s et of environmental factors. Significant predictors of YOY walleye gro wth were May, June, and August cumulative degree days, as well as the growth of older walleye. We expected the set of factors which affect f reshwater drum, Aplodinotus grunniens, to include factors that affect walleye, such as temperature, shared prey availability, and abundance of both walleye and drum. As a lest, environmental growth coefficients computed by Pereira (1992) for freshwater drum were compared to walle ye growth coefficients. The growth coefficients of drum were significa ntly positively correlated with the walleye coefficients, and the sign ificance increased if the poorest walleye growth years were excluded.