Morphometry of the cisco, Leucichthys artedi (Le Sueur), in the lakes of the Northeastern Highlands, Wisconsin

Abstract

In an earlier study (Hile, 1936) a detailed investigation was presented of the age and growth of the ciscoes of Trout Lake, Musckellunge Lake, Silver Lake, and Clear Lake in northeastern Wisconsin. It was demonstrated that the growth rate of the cisco varies widely from lake to lake within the same geographical area, and that these differences in growth rate show a close correlation with certain environmental conditions. The present study of the morphometry of the cisco populations of these same four lakes may be considered a continuation of the earlier investigation, since emphasis will be places on the problem of the relationship between the growth rate and morphological characteristics of the cisco. Attention will be given also to the existence of fundamental structural differences between year classes of the same population, differences that must be considered the result of variation from one calendar year to another in the environmental conditions at the time of the early growth and development of the cisco.