Trends in Percid Yields from Lake of the Woods, 1888–1973

Abstract

Commercial yields of walleye (Stizostedion vitreum vitreum) increased from 1888 to the mid-1930s and then gradually declined to 1973. Commercial yields of sauger (S. canadense) and yellow perch (Perca flavescens), first recorded in 1926, were more stable than walleye yields. The increase in walleye yields was associated with declines in the yield of lake sturgeon (Acipenser fulvescens) and lake whitefish (Coregonus clupeaformis). Walleye yields declined from 1.7 kg∙ha−1 annually in the 1930s to 0.8 kg∙ha−1 during 1964–73. Exploitation by commercial and sport fisheries appeared to be the main cause of the decline. Creel surveys from 1967 to 1971 indicated that the sportfishing yield exceeded the commercial yield, and the combined harvest was near the high levels in the 1930s. Wider fluctuations in yield observed since the 1950s suggested that recruitment had become more variable. Short-term increases in growth rate were observed in one area after intensive walleye harvests, but in other parts of the lake no change in growth rates was observed. Sauger appeared to be increasing in abundance in the northern areas of the lake, probably in response to increasing turbidity. Key words: Percidae, yield trends, Stizostedion, Perca, harvest