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.
In general, people who live around Superior know only their own neck of the woods. "There she is, Lake Superior!" exulted Woodrow Wilcox of Brimley, Mich., a commercial fisherman setting out one morning recently to lift his herring nets. Wilcox gestured with his arm, and there, as far as the eye could see, was a limitless expanse of water. A glance at the map later revealed that Wilcox was gesturing toward Whitefish Bay, just a tiny pocket on the southeast side of the lake.
During a storm, Superior can be more dangerous than the ocean. Among commercial fishermen, it is known as "the lake that never gives up her dead." Year-round the water, except in the shallows, is a constant 39.2° Fahrenheit, and it is said that the body of anyone who drowns in mid-lake sinks to the bottom never to arise.
There is some plant growth in the shallow areas of the lake, but for the most part vegetation is sparse. Except for the Bad River Slough in Wisconsin, where the Chippewa Indians harvest wild rice, there are virtually no marshes, and as a result, few ducks and geese are seen. Because of the low temperature of the lake, fall in the area is pleasantly long and cool, while spring is often short and harsh. For four months of the year ice closes the lake to shipping. The center almost never freezes over, but inshore the ice is of sufficient thickness to support automobiles. In fact, during the winter the town of LaPointe on Madeline Island maintains a stretch of lake ice as a road to Bayfield on the mainland.
Geologically, much of the lake basin lies on the Canadian Shield, a block of igneous and metamorphic rock, mostly granite, that dates as far back as 3½ billion years. Fossils of microscopic organisms two billion years old have been found on the northwest shore of the lake. It is thought that before the arrival of the first glacier Superior was part of a great river valley that extended to the Atlantic, and it became a lake as a result of glacial erosion.
Indians moved into the region about 10,000 years ago, and the tribe encountered by early white explorers was the Ojibway, or Chippewa, an Algonquin-speaking people celebrated by Longfellow in The Song of Hiawatha. They called Superior Gitche Gumee or "great sea." The real Hiawatha, however, was not an Ojibway but a hero of Iroquois legend. With poetic license, Longfellow transported him west to the shores of Gitche Gumee.
The first European to discover the lake probably was Etienne Brulé, lieutenant to Samuel de Champlain, in the year 1622. The Brulé River in Wisconsin, one of the excellent trout streams tributary to Superior, is named after him. To Brulé and Champlian, Superior was known as Grand Lac, but French Jesuits later called it Lac Supérieur, meaning it was above Lake Huron. Some explorers were interested in venturing to the western end of Superior because they thought it might be the northwest passage to China. Indeed, Jean Nicolet arrived in Green Bay in 1634 wearing a damask robe for the mandarins whom he expected to meet there. Duluth itself is a corrupted contraction of Sieur Du Lhut, the title of Daniel de Greysolon, a trader who obtained dozens of canoeloads of furs from the area in 1680.
In the 1840s and 1850s, copper and iron were discovered on the Upper Peninsula of Michigan and along the southern shore of Superior. On the Canadian side of the lake the land supported a spruce and balsam forest that gave rise to a pulp-and-lumber industry. With the opening of the Soo locks at Sault Ste. Marie in 1855, the lake's economy boomed, and settlers poured into the Upper Peninsula, northern Wisconsin and Minnesota. Many of them were Swedes, Norwegians and Finns, lured by the writings of Fredrika Bremer, Sweden's first lady of letters, who visited the Superior region in the 1840's and envisioned it as a new Scandinavia.
Compared to the other Great Lakes areas, the Superior basin is sparsely populated, with less than 30 inhabitants to the square mile. Since the completion of the Trans-Canada Highway in 1960, it is possible to drive around the lake by automobile. In the summer months the 1,300-mile Lake Superior Circle Route is heavily traveled by campers and tourists, but most of all by fishermen.
It appears paradoxical that a lake as clear and sterile as Superior could yield the fish it has. "The answer is spatial," says Jim Selgeby, a young biologist of the U.S. Bureau of Sport Fisheries laboratory in Ashland, Wis. "The lake is not rich, but it has a great depth of production. The fish have no feeding problem at depths of 300 to 400 feet. There is tremendous depth of water, and it is all usable because there is no oxygen depletion. In many other lakes there is oxygen depletion on the bottom from organic sediments, but here we have very little."
Fish arrange themselves in tiers like office workers in a skyscraper. Northern pike, walleyes, yellow perch, smallmouth bass and sunfish occupy the shallow bays. Lake sturgeon, now rare, common suckers and the northern sturgeon sucker live in the shallows and down to a depth of 150 feet. The lake herring or cisco, a member of the delectable whitefish family, inhabits depths of 250 feet. Lake trout occupy similar depths, although they may go deeper. Inshore, the whitefish descends to at least 400 feet, while other members of the family—the bloater, the kiyi and the shortjaw chub—are found from 200 to about 600 feet down in company with the burbot, a freshwater codfish. The deepwater sculpin dwells from 100 feet to the bottom. Indeed the only sculpin specimens collected by the late Dr. Samuel Eddy of the University of Minnesota were taken from the stomachs of siscowets, a very fat subspecies of lake trout that inhabits the abyssal depths.
Of all the fishes in Lake Superior, none is more highly prized by commercial fishermen than the whitefish. Early explorers, who often had to exist on fish, reported that the whitefish, no matter how often eaten, never jaded the appetite.
The lake trout are a saga in themselves. Until the 1950s both commercial fishermen and anglers caught them in great numbers, some weighing as much as 60 pounds. Then the sea lamprey invaded Lake Superior. Where it originated is a mystery. A landlocked form was present in the Finger Lakes of central New York in the early 19th century, and the species apparently spread into Lake Ontario through the newly constructed canal system. In the 1920s the lampreys moved up through the Welland Canal into Lake Erie, some of them pushing on into Huron and Michigan. By the mid-1940s the lake trout, whitefish and chub in Huron and Michigan were under especially severe attack by these predators.
The Soo locks slowed the lamprey invasion of Lake Superior, but eventually they did pass through in numbers, some gaining entry by attaching themselves to the hulls of ships. By the early 1950s they had established spawning runs in about 120 streams flowing into Superior from the U.S. shore.
Electrical barriers were set across streams but did little to stop the lampreys, and Dr. Vernon Applegate of the U.S. Bureau of Commercial Fisheries was put in charge of a research program to see if a chemical could control them. It took Applegate's unit seven years to devise TFM, a selective chemical poison, which was then applied to streams to kill the young lampreys or larvae. For the first three to eight years or so of its life the sea lamprey is harmless, leading a larval existence in stream muds, filtering microscopic organisms for food. When it becomes an adult, it leaves the stream to feed upon fish. The chemical proved successful and was soon applied to tributaries of Michigan and Huron. Superior did not suffer as great a loss of lake trout as the other Great Lakes, but ever since the arrival of the lamprey, biologists have had to rely on stocking the trout, rather than on natural reproduction, to build up the population. Since 1958, more than 34 million young lake trout have been planted in Superior, and even more will probably be required if natural reproduction is to become viable.
With the sea lamprey under control, attention has turned to other fish invaders. The alewife, which gained entry to Huron and Michigan, has made an irruption in Superior but it has not yet become a problem, apparently because of the low water temperatures. The smelt is another story. An anadromous fish native to the Atlantic Coast, smelt were stocked in a tributary of Lake Michigan in 1912. They were first recorded in Lake Superior in 1930, and by 1952 their numbers had increased to the point where commercial fishermen began harvesting them. The catch now exceeds one million pounds a year. What effects the smelt have had on the ecology of the lake are not well understood. In some parts of Superior they have replaced the chub as the main food of big lake trout, but they may have depressed the stocks of lake herring by competing for their food. The lake herring, already in decline because of commercial fishing pressure, may soon disappear from Superior as it has from the other Great Lakes, unless restrictive measures are taken. Michigan, Wisconsin and Minnesota, for instance, have curtailed commercial fishing on inshore spawning grounds.
Of all the fishes sought by anglers, the lake trout is the prime quarry. There are charter boats available for lake fishing in Brimley and Munising, Mich., Ross-port, Ontario and other locales, but the most notable fleet, a cooperative of 13 boats, is at Bayfield, Wis. Modern cabin cruisers equipped with twin V-8s can each troll up to 12 lines. The season runs from May until October, and the rate per boat is $120 a day.
Before the advent of the lamprey, lake trout comprised 99% of the sports catch. Now one can expect a mixed creel of lake trout, rainbows, steelhead, brook trout and occasionally coho salmon, which have enjoyed neither the success nor reputation they have earned in Lake Michigan, probably because they do not have the alewife as forage. In season, excellent trout fishing is to be had in tributary streams. As a matter of fact, a longstanding world-record brook trout of 14½ pounds was caught in the Nipigon River in 1916.
Superior displays some instances of localized pollution. In Nipigon Strait, Ontario, for example, so much debris lies on the bottom from log drives that the area cannot be fished with nets. A population of walleyes in Nipigon Bay has been wiped out, apparently because of pulp-mill wastes. Lake trout cannot be taken and sold commercially from Thunder Bay, Ontario on account of excessive mercury levels in their flesh. (Mercury is used in processing pulp.) There are also high levels of mercury in lake trout caught near Marathon, Ontario, and Marathon, Nipigon and Thunder Bay often smell of hydrogen sulphide from the mills. Local boosters call the stench "the smell of money." Several years ago an outraged resident of the Fort William section of Thunder Bay erected a billboard on its outskirts that read: "You are now leaving Fort William—Resume Breathing." Angry politicians had it torn down.
On the American side conditions are worse. According to the Northern Environmental Council Wisconsin's scenic shoreline is being eroded because of mismanagement of the Soo locks' water levels by the International Joint Commission, a body set up to administer the boundary waters, and by the U.S. Corps of Engineers. By keeping the levels artificially high in the lake, the subsequent wave action caves in red clay banks, thereby increasing the turbidity of the waters. Red-clay erosion is also a problem in a number of Wisconsin tributaries, where destructive logging, poor farming practices and inadequate road maintenance have exposed soils to runoff, causing abnormal sedimentation.
Another point of contention is the St. Louis River, which flows into Duluth harbor and suffers from municipal and industrial pollution that has caused extensive fish kills. The St. Louis, the major U.S. tributary to Superior, undergoes additional indignity as it flows through Minnesota's Jay Cooke State Park. It does not flow at all there in the summer months because the Minnesota Power & Light Company diverts the river water for the operation of a power plant.
Given the condition of the St. Louis, it is perhaps ironic that people in Duluth should complain about what Reserve Mining is dumping in the lake. But then, anyone anywhere on the lake should be concerned about what might happen to this giant but fragile body of water. As a pair of Canadian biologists, Richard A. Ryder and Lionel Johnson, told fellow scientists at the international symposium on oligotrophic lakes, Lake Superior and others like it "should be recognized for what they are, swimming pools carved out of granite, with low-nutrient tributaries and a cold annual thermal regime. They are capable of having their environment and their communities severely altered—only too easily. Unless further increases of eutrophication and exploitation are brought to a halt, the lakes will be altered within the next three decades and their demise...may then be irrevocable."