An Illustrated Guide to the Identification of the Planktonic Crustacea of Lake Michigan with Notes on their Ecology

Abstract

Although reported observations on the planktonic crustacea in Lake Michigan began over a century ago (Hoy 1872), much remains to be learned about the general biology as well as the trophic relations of these animals. The planktonic crustacean community (including the benthic amphipod, Pontoporeia) provides the major portion of available food for the greater mass of the lake's fish populations. Management of the lake as a valuable natural resource must be based on a knowledge of the lake's biological processes and potentials. The crustacean plankton community forms the major link between algae and fish and, for this reason, should be considered an important area for future study. Although much is known about the crustacean plankton in terms of taxonomy, and seasonal and vertical distribution (Wells 1960, 1970; McNaught 1966; McNaught and Hasler 1966; and Gannon 1972a), little is known of the population dynamics, production, and feeding of these animals. The purpose of this guide is to facilitate easy and rapid identification of the common planktonic crustaceans of Lake Michigan with the hope of aiding and promoting further study concerning their biology.