Relationship of Condition of Walleye (Stizostedion vitreum) and Northern Pike (Esox lucius) to Water Clarity, with Special Reference to Dauphin Lake, Manitoba

An examination of 37 lakes in the central region of Canada revealed that the summer condition of northern pike, Esox lucius, was correlated with Secchi depth but there was no such correlation for walleye, Stizostedion vitreum. A study of the diets of the two predatory fish coexisting in a prairie lake, showed overlap in the food items selected in July. Food density did not appear to be limited. Walleye food consumption rose from about 1% bodyweight in the spring to 2% in late summer and was less than 1% in the late autumn and early winter. Pike food consumption was similar except it rose to over 3% in the early winter when the lake froze over and the water cleared. High turbidity in the prairie lake during the open water period may have reduced the ability of pike to feed.