The Length-Weight Relationship, Factors for Conversions between Standard and Total Lengths, and Coefficients of Condition for Seven Michigan Fishes

Abstract

A heavy loss of fish occurred in the Yahara River below Lake Kegonsa, Wisconsin, during the latter part of September and the early part of October, 1946. All species of fish in the river were affected in the mortality. The fish, crowded close to shore, were breathing at the surface and showed marked signs of distress before expiring. Chemical analyses of the water were made in successive periods, and experiments were performed to determine the toxicity of the river water to experimental fish. Death was attributed primarily to the depletion of the oxygen supply by the decomposing algal mass consisting of almost a pure culture of Aphanizomenon flos aquae. Secondarily, toxic substances liberated into the water by the decomposing algae probably contributed to the death of the fish.