Fisheries management to reduce contaminant consumption

Lake Michigan is a microcosm of global environmental issues. A history of problems has plagued the lake, arising from the wide range of human activities the basin supports. Much of Lake Michigan`s watershed is agriculturally developed, and the shoreline is dotted with major urban, industrial centers. The lake has supported important commercial shipping and fishing industries for more than a century. In the 1960s and 1970s eutrophication was a concern. More recently toxic contaminants, particularly PCBs, and invasions by exotic species, such as the zebra mussel (Dreissena polymorpha), have captured headlines. More than 200 years of development and exploitation have taken Lake Michigan far from a pristine state. The Lake Michigan fishery in intensively managed, and food web manipulation may more effectively reduce PCB exposure than cleanup activities do. Four management options are discussed in this article: trophic cascade; growth maximization; size of stocked fish; and selective species stocking. The most promising option, well supported by data is in many ways the simplist: selective stocking of species that accumulate contaminants at the lowest levels. 51 refs., 6 figs., 1 tab.