would be expected in older bodies of water of 

 comparable size and composition. As pointed out 

 by Tanner (1965), the fish life in the Great Lakes, 

 just prior to the appearance of the sea lamprey was 

 relatively thin, with fragile and unstable relations 

 among predators and their prey. As a result, the 

 biological balance of the Great Lakes has been up- 

 set to an astonishingly large degree by a series of 

 shocks; the introduction of exotic species, some 

 from saltwater and some from fresh; man's own 

 selective fishing activities; and the flagrant pollu- 

 tion and misuse of the coastal zones of the Great 

 Lakes. 



No other factor has done as much to damage 

 the aggregate economic productivity of the Great 

 Lakes fisheries as the invasion of the sea lamprey. 

 Originally landlocked in Lake Ontario, this nor- 

 mally saltwater parasite found its way into the 

 other Great Lakes through the Welland Canal. 

 Water conditions in Lake Erie prevented any major 

 destruction there, but when the lamprey moved 

 into Lakes Huron, Michigan, and Superior, it 

 expanded very rapidly with disastrous effects on 

 some of the most valuable fish stocks in the lakes. 

 The lamprey was particularly devastating to the 

 lake trout, but it also attacked other valuable 

 species, such as burbot and whitefish. Within a few 

 years it had literally eliminated some of the major 

 commercial fishing operations on the Great Lakes. 

 An idea of the magnitude of its impact can be 

 gleaned from the fact that the lake trout fishery, 

 once valued at more than $4 million annually, had 

 dropped to less than $100,000 in the 1960's. 



The effect of the lamprey invasion spread even 

 further. It led to greater concentration of fishing 

 effort on the remaining valuable species, with 

 serious effects on these populations and on the 

 total stock of predators. Partly because of this, the 

 alewife, another saltwater fish long known in Lake 

 Ontario, suddenly exploded into phenomenal 

 growth in Lakes Huron and Michigan about 1955. 

 Tills latest intruder is unwelcome in several re- 

 spects; it is not directly usable for human con- 

 sumption and brings prices of only $15 to $20 per 

 ton for fishmeal and oil or for pet food. More 

 important, it is competitive with a variety of other 

 species, for example, chubs, lake herring, and 

 shiners. On the other hand, it serves as an excellent 

 forage fish for trout and the recently introduced 

 coho and chinook salmon. The success to date of 



these introductions may be due, in part, to the 

 abundance of alewives. 



It has been argued by some biologists that the 

 dangerous instability of the Great Lakes fish 

 populations will be increased by the tremendous 

 dominance of the alewife. At present, it probably 

 represents 90 percent of the total tonnage of fish 

 in the Great Lakes. Greater stabiUty and produc- 

 tivity might be achieved if a multiple species 

 complex of prey and an appropriate balance of 

 predators, both natural and human, could be 

 re-established, but this remains a matter of disa- 

 greement. 



The Commission's deep concern over the deteri- 

 oration of water quality in the Great Lakes has 

 been developed more fully in the reports of other 

 panels and need not be repeated here. We simply 

 note that the problem has many dimensions that 

 touch the fisheries, usually adversely. Industrial 

 wastes and oxygen—depleting organisms fertilized 

 by processed sewage have taken their toll. Unwise 

 development of agricultural and forested areas has 

 damaged the nearshore environment through soil 

 erosion. Herbicides and pesticides have reached 

 dangerous levels in many parts of the Great Lakes. 

 The constant pressure for industrial and commer- 

 cial locations on the lake front has inflicted 

 irreparable damage on the shoreline environment 

 in many areas, with consequent reductions in fish 

 productivity. 



c. The Future Outlook It would be fatuous to 

 argue that all of these adverse effects on the 

 commercial and sport fishing potential of the 

 Great Lakes could be reversed through imple- 

 mentation of a single set of recommendations, 

 however wise. The land-water interface of the 

 Great Lakes will continue to become more con- 

 gested, and the impact of the tremendous popula- 

 tion and industrial concentration in the North 

 Central states will inevitably involve some costs in 

 terms of environmental quality in all the. Great 

 Lakes. Nevertheless, there is evidence of sufficient 

 public concern and of well conceived action 

 programs to warrant limited optimism for the 

 future. Cooperative efforts by the Canadian and 

 U.S. governments, the States, and the Province of 

 Ontario have brought the sea lamprey under 

 control in Lake Superior, and the situation is 

 sufficiently well in hand in Lake Michigan to make 

 it feasible to undertake major rebuilding programs 



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