Changes in the Fish Species Composition of the Great Lakes

Abstract

This paper is an interpretive review of the "case histories" which documented the changes in each of the Laurentian Great Lakes for the 1971 symposium on Salmonid Communities in Oligotrophic Lakes (SCOL). It suggests that lakes Huron, Michigan, and Superior passed through a parallel series of stock changes after the invasions of those lakes by the sea lamprey. First, the lake trout and burbot stocks collapsed, and then with the relaxation of predation pressure rainbow smelt, deepwater cisco, and alewife stocks increased. Lake herring stocks collapsed in apparent response to the smelt increase. Whitefish were affected by sea lamprey but recovery after the control of the lamprey in lakes Michigan and Superior suggested that the exotic species had little influence. Lake Ontario differed from the other lakes in that it was inhabited by both sea lamprey and alewife before the turn of the century, and provided the reservoir from which these species expanded to colonize the upper lakes. Alewife apparently equilibrated early, but the evidence was that more recent perturbations allowed the sea lamprey to become a significant factor in the loss of the piscivores of Lake Ontario. Subsequent proliferation of ciscoes and smelt, and collapse of the herring, followed a sequence similar to that of the upper lakes. Lake Erie seemed to be similarly affected by loss of predator stocks, but its predominantly eutrophic character made the situation more complex. Overfishing was indicted in many early stock collapses, in the early invasion of the smelt in lakes Huron and Michigan and in the recent cisco declines of lakes Ontario and Huron. Eutrophication and more direct pollution stresses had mainly inshore impacts, but the similarity in the species sequencing in the oligotrophic Great Lakes suggested that although these factors may have supplemented the other effects, their influence before about 1950 was less than that of overfishing and the invasion of exotic species. Control of sea lamprey, overfishing, and eutrophication seemed attainable in the Great Lakes, but the only defense against further invasions by pest species appeared to be maintenance of sufficiently dense piscivore stocks to assure their suppression. Determining the levels of harvest appropriate to this provision will require intensified research.

Recent shifts in Daphnia community structure in southeastern Lake Michigan: A comparison of the inshore and offshore regions1,2

“…Thus Eddy (1927) The earliest quantitative zooplankton data for the offshore region are from a station 13 km offshore of Grand Haven in 74 m of water in 1954 (Wells 1960). In the mid1950s the alewife population was low, while lake herring populations were high with commercial catches in 19 54-l 9 5 5 similar to those in 1930-1932(Moffet 1956Christie 1974). Lake whitefish populations were less abundant than in earlier times; commercial catches were much smaller than in the 1880s and somewhat smaller than in the early 1930s (Wells and McLain 1973).…”

“…With no significant predation by the reduced lake trout (Salvelinus namaycush) populations, and with reduced competition from lowered populations of endemic planktivores, the planktivorous alewife rapidly dominated the Lake Michigan fish community (Christie 1974). Furthermore, zooplankton community structure apparently was altered as a consequence of eutrophication and the alewife population explosion (Brooks 1969;Wells 1970;McNaught 1975).…”

Reintroduction of Lake Sturgeon (Acipenser fulvescens) into the St. Regis River, NY: Post- Release Assessment of Habitat Use and Growth

“…However, by 1900 the population component had declined such that the commercial catch was insignificant, and this fishery is often cited as a classic example of over-fishing (Christie 1973). Commercial harvest of lake sturgeon was banned in New York State in 1976, andin Ontario in 1978. Currently no commercial or recreational harvest is permitted in Lake Ontario waters.…”

The Report of the Ecological Society of America Committee on the Scientific Basis for Ecosystem Management

“…The food web of Lake Michigan has been completely reconfigured by exotic species invasions, fishing, and stocking of sport fishes. Overharvest and the parasitic sea lamprey contributed to the collapse of lake charr and native coregonine populations shortly after World Warii (Christie 1974). Exotic zooplanktivores, especially alewife, irrupted while the lake's populations of large piscivorous fishes were low.…”