Decline Of The Lake Trout Fishery In Lake Michigan

Examines the history of human use of the fish resources of the Great Lakes, and analyzes the changing nature of the fish populations, especially those that became popular in the commercial markets.

Fishing the Great Lakes is a sweeping history of the destruction of the once-abundant fisheries of the great "inland seas" that lie between the United States and Canada. Though lake trout, whitefish, freshwater herring, and sturgeon were still teeming as late as 1850, Margaret Bogue documents here how overfishing, pollution, political squabbling, poor public policies, and commercial exploitation combined to damage the fish populations even before the voracious sea lamprey invaded the lakes and decimated the lake trout population in the 1940s. From the earliest records of fishing by native peoples, through the era of European exploration and settlement, to the growth and collapse of the commercial fishing industry, Fishing the Great Lakes traces the changing relationships between the fish resources and the people of the Great Lakes region. Bogue focuses in particular on the period from 1783, when Great Britain and the United States first politically severed the geographic unity of the Great Lakes, through 1933, when the commercial fishing industry had passed from its heyday in the late nineteenth century into very serious decline. She shows how fishermen, entrepreneurial fish dealers, the monopolistic A. Booth and Company (which distributed and marketed much of the Great Lakes catch), and policy makers at all levels of government played their parts in the debacle. So, too, did underfunded scientists and early conservationists unable to spark the interest of an indifferent public. Concern with the quality of lake habitat and the abundance of fish increasingly took a backseat to the interests of agriculture, lumbering, mining, commerce, manufacturing, and urban development in the Great Lakes region. Offering more than a regional history, Bogue also places the problems of Great Lakes fishing in the context of past and current worldwide fishery concerns.

Data collected during successive years (1971-79) of sampling lake trout in Lake Michigan were used to develop statistics on lake trout growth, maturity, and mortality, and to quantify seasonal lake trout food and food availability. These statistics were then compiled with data of lake trout year-class strengths and age-specific food conversion efficiencies to compute production and forage fish comsumption by lake trout in Lake Michigan during the 1979 growing season. Lake trout consumed an estimated 3,037 t of forage fish, to which alewives contributed about 71%, rainbow smelt 18%, and slimy sculpins 11%. Seasonal changes in bathymetric distributions of lake trout with respect to those forage fish of a suitable size for prey were major determinants of the size and species compositions of fish in the seasonal diet of lake trout.