The Growth of the Muskellunge, Esox masquinongy immaculatus (Garrard), in Various Lakes and Drainage Areas of Northern Wisconsin

Abstract

T HIS study of muskellunge growth is a continuation of the game fish studies undertaken by the Wisconsin Geological and Natural History Survey since 1928. In the summer of that year the late Dr. G. I. Kemmerer, in cooperation with the U. S. Bureau of Fisheries, interested a considerable number of Wisconsin anglers in research on the growth of game fish and obtained scales and data from the fish they captured. This cooperative enterprise has continued up to the present time with the result that a scale collection representing 3500 specimens of game fish is now at the disposal of fishery biologists at the University of Wisconsin. The willingness of anglers to cooperate in these studies is noteworthy and especially significant from the conservationist's viewpoint. The 8 years of cooperation between anglers and fishery investigators show that fishermen are deeply concerned over the preservation of their game stock. Within 2 years after the inauguration of the program, sufficient data were on hand to make a study of the growth rates of the valuable game species. The first report appeared in the spring of 1930 (Juday and Schneberger, 1930). It stated the age-length relationships of 10 game species, based on an examination of the scales of 336 specimens taken by anglers and scales from 164 individuals collected by Bureau of Fisheries investigators during the 1927 and 1928 seasons at the Trout Lake Laboratory. Thirtyeight of the 500 individuals represented in the 1930 scale collection were muskellunge. Twenty-five of these had been caught by anglers and the remainder by investigators. All of the specimens taken by the latter measured below the legal length of 30 inches. The scales from these young individuals were of considerable value in the present study. Their conspicuous annuli gave the author a definite idea concerning their nature and made age determination of these scales a simple task. In the second place, the actual lengths of these specimens verified the calculated lengths, for the earlier years of life, made from the scales of the older individuals. The rapid accumulation of data made possible a second report of game fish growth in 1933 (Juday and Schneberger, 1933). By this time the scale collection had increased to 1100, largely through the splendid cooperation of the fishermen. Their hearty response made it necessary to limit the number of species considered to the 5 most important, namely, the muskellunge, Esox masquinongy immaculatus (Garrard), northern pike, Esox lucius Linnaeus, wall-eyed pike or yellow pike-perch, Stizostedion vitreum (Mitchill), large-mouthed black bass, Aplites salmoides (LacepDde), and the small-mouthed black bass, Micropterus dolomieu (Lacbpide).