Superior is an unusual body of water; it is an extraordinary lake. Although Lake Baikal in Siberia contains more water because it is deeper, Superior is the largest freshwater lake in the world in surface acreage, covering more than 32,000 square miles. To limnologists, scientists who study lakes, Superior is the classic "oligotrophic" lake, the term applied to very deep, very cold, very clear lakes. The limnology of the lake, its internal dynamics, its ecosystem of mysid shrimp, deepwater ciscoes, bloaters, whitefish and lake trout make it fragile to an extreme. Superior is tremendously different from the typical "eutrophic," or nutrient-enriched, bass lake that most Americans know. It is a delicate giant of another time, another creation—a giant that is in dire danger of being toppled by pollution. Perhaps its most heinous polluter is Reserve Mining of Silver Bay, Minn., whose plant was shut down last month. For two days.
In what is now the longest conservation trial in the country's history, the U.S. Government, the states of Minnesota, Wisconsin and Michigan and a number of citizen organizations like the Northern Environmental Council have sought to prevent Reserve from dumping 67,000 tons of taconite tailings a day into Lake Superior. Jointly owned by Armco and Republic Steel, Reserve has been in business there for 19 years. It mines taconite, a flintlike rock found in the nearby Mesabi Range that contains iron in small quantities, and extracts the ore through a magnetic process. Made into pellets, the iron is shipped to steel mills, and the tailings, or wastes, crushed into particles finer than flour, are dumped into the lake where, the company claims, they sink harmlessly into the 900-foot-deep Great Trough off Silver Bay.
Not so say the plaintiffs, who want Reserve to dump the tailings on land instead of in the lake. The plaintiffs contend that the dumping has polluted the lake with asbestos-like fibers that may cause cancer in residents of Duluth, 60 miles south of Silver Bay, and in four other communities that draw drinking water from Superior.
Last month, after Reserve argued that it could dump on land only with government financial aid, U.S. District Judge Miles Lord ruled, "Up until the time of writing this opinion the court has sought to exhaust every possibility in an effort to find a solution that would alleviate the health threat without disruption of operations at Silver Bay. Faced with the defendants' intransigence, even in the light of the public-health problem, the court must order an immediate curtailment of the discharge."
The plant shut down, but operations and dumping resumed 48 hours later when an emergency panel of three circuit-court judges met in a Missouri motel to issue a temporary stay of Judge Lord's decision. The federal court of appeals is expected to rule on the stay this month, and whatever the outcome, the verdict probably will be appealed to the Supreme Court. Meanwhile, 67,000 tons of taconite tailings a day continue to pour into the lake. To anyone who knows Lake Superior, the final decision is of utmost importance.
Superior is to most lakes what the finest cut glass would be to no-deposit beer bottles, but for all its naturally fine qualities, it can be a most frustrating lake to study or to fish. It is so vast that U.S. and Canadian scientists have been mostly restricted to inshore areas, trying to fit bits and pieces of data together. It is so deep in places (1330 feet) that the bottom life can only be guessed at, and the clarity at depths of more than 50 feet makes it difficult to trawl a net for fish because they can see it coming.
Until recent years much of the existing information about Superior had been gathered more than a century ago by Louis Agassiz, a Harvard professor of geology and zoology, who led an expedition to the Canadian shore of the lake in the summer of 1848. Agassiz' party included four fellow naturalists, two Bostonians described as "admiring and cultivated" and nine Harvard students seeking fresh air and sunshine. They worked-for six weeks from three canoes and a dory, then returned to Cambridge to publish their findings about the rocks and fish they saw.
Agassiz apart, information on Superior and the four other Great Lakes is also to be found in a special issue of the Journal of the Fisheries Research Board of Canada published in June, 1972. Entirely given over to papers delivered at an international symposium on salmonid communities in oligotrophic lakes, the volume makes for both fascinating and gloomy reading. Green Bay, which has yielded about half of the total production of commercial fish in Lake Michigan, is covered in good part with anoxic gray sludge. In Lake Huron, Saginaw Bay suffers heavily from pollution, and Lake Erie is an infamous disaster. Far less publicized is the plight of Lake Ontario, which has lost its native stocks of landlocked salmon, lake trout, whitefish and ciscoes. Perhaps the only gamefish population still healthy is the smallmouth bass for which Ontario is famous. In the bay of Quinte, however, they have declined because of competition from white perch, which moved in from canals that connect it to the Hudson River.
The report on Superior was delivered by A. H. Lawrie and the late J. F. Rahrer, biologists for the Ontario government, who noted that every commercial species of fish had been severely depleted. This happened in good part because fishermen were catching stocks confined to a particular part of the lake, and having fished up one area, moved to another. "In this way," Lawrie and Rahrer explained, "stock after stock was depleted while conventional yield statistics gave an impression of relative stability." Under government regulation, there has been some recovery, and up-to-date hatcheries offer further promise.
Rejuvenating the fish populations of Lake Superior might seem like trying to stock the ocean. Indeed, in many ways, Superior appears to have more in common with the ocean than with most lakes, a situation that has not been lost on local chambers of commerce that call the lake "the inland sea." The U.S. Government is buying up the Apostle Islands off the Wisconsin shore as a National Lake-shore, and tourists who throng to Bay-field, Wis., a picturesque town that looks like a New England fishing village, are exhorted to go "deep-sea fishing" for trout. Duluth, connected to the Atlantic by the St. Lawrence Seaway, ranks as the third largest seaport in the U.S., and the Sault Ste. Marie locks at the eastern end of the lake handle more tonnage than did the Panama and Suez canals combined at their busiest.