Sweetwater Seas Under Siege - Part 2: The Great Salmon Swindle: How One Biologist Traded Native Fish for a Sport Fishing Fantasy

The Sweetwater Seas Under Siege - Part 2: The Great Salmon Swindle: How One Biologist Traded Native Fish for a Sport Fishing Fantasy

The massive 1967 die-off of alewives forced the Great Lakes ecosystem into a state of ecological chaos. These silvery river herring, native to the Atlantic, had used the breached canals to invade Lake Michigan decades earlier. They comprised 90 percent of the total fish mass in Lake Michigan by the 1960s.

In June 1967, a Navy seaplane surveyed the southern end of the lake. The pilot observed white streaks stretching for miles across the surface. This slick was hundreds of millions, possibly billions, of dead and dying alewives. When the winds shifted, this fetid mass washed ashore. The resulting rot smothered 30 miles (48.3 km) of Chicago shoreline, in places reaching shin-deep. City workers disposed of enough rotting alewives to cover two football fields 500 feet (152 m) high. The cleanup cost the tourism industry millions. This biological disaster demanded a radical response.

Two Competing Solutions to Chaos

The problem traced back to the previous invader: the sea lamprey. The lamprey had decimated native predators like the lake trout. Without the lake trout to keep them in check, alewife populations swelled to “almost incredible” numbers.

Biologist Vernon Applegate, the man who found the poison to control the lamprey, favored restoring the ecosystem’s native balance. He planned a massive hatchery program to resuscitate the lake trout populations. Lake trout were uniquely evolved to thrive in the complex Great Lakes environment. They represented a natural “immune system” for the lakes.

However, the new Michigan fishery boss, Howard Tanner, had a different plan. Tanner inherited a system in shambles, essentially a blank ecological slate. He viewed the immense alewife population not as a plague, but as an opportunity to raise predator fish. Tanner aimed to give Mother Nature an upgrade, focusing on recreation over restoration.

The Fishery Architect’s Ethos

Born in northern Michigan, Tanner developed a passion for fishing early, using his skill to help feed his family during the Great Depression. He later earned a doctorate in fisheries biology after returning from World War II.

Tanner saw Great Lakes waters as the Midwest’s “last frontier for recreation”. He believed the resource should be managed to “produce the greatest good for the greatest number”. For Tanner, this meant shifting management away from a self-sustaining food supply and toward sport fishing thrill.

His philosophy was reinforced by the postwar mentality of his colleagues. Tanner, who had built airstrips in the South Pacific, adopted a determined, “get it done” attitude toward environmental engineering.

Tanner quickly ruled out the native lake trout for this new vision. He argued that lake trout were not “sexy enough” because they did not put up much of a fight when hooked. When pulled quickly from deep water, the pressure change can inflate a lake trout’s swim bladder, making it surface “almost like a balloon”. Tanner concluded he was “just not very enthusiastic about lake trout”.

The Search for a Substitute Predator

Tanner sent his lieutenant, Wayne Tody, to find an exotic predator. The initial candidate was the Striped Bass, a large predator from the Eastern Seaboard. Stocking experiments in Western reservoirs had shown “stripers” could live exclusively in freshwater. Striped Bass are known to grow quickly and fight hard, meeting Tanner’s criteria for sport fish.

However, a South Carolina specialist determined the Great Lakes were too frigid. Furthermore, the lakes lacked the long, undammed rivers necessary for bass spawning.

Tody then turned his attention to Pacific salmon. Pacific salmon are naturally built to feast on schooling prey fish like alewives. Crucially, salmon can quickly expel gas from their swim bladder. This allows them to maintain their “ferocious fight all the way to the deck of a boat”.

Tody discovered that new hatchery techniques were yielding surplus eggs in the West. A key innovation was the “Oregon Moist Pellet,” a newly concocted fish food that made the fish more vigorous and durable. Tanner immediately called Oregon and secured a gift of one million Coho (silver) salmon eggs. This decision marked the beginning of a radical ecological experiment.

Ignoring Past Warnings

Tanner knew the intentional introduction of exotic species into the Great Lakes was deeply controversial. In the 1870s, the U.S. Fish Commission deliberately stocked common carp. These bottom-grubbers ravaged lake bottoms, muddying waters across the lakes. Later, the introduction of Atlantic rainbow smelt in 1912 led to the ravaging of native juvenile fish like perch and lake trout.

The U.S. Bureau of Fisheries issued a firm admonition in a 1926 report. They argued against importing any “uncontrollable indigenous animal” due to previous damage. Nearly 40 years later, Tanner was willing to accept the responsibility of introducing Pacific salmon, driven by the belief that “Nobody ever had that much water with that much food supply” (alewives).

The High-Stakes Gamble

The initial plan involved stocking Coho for three consecutive years. This was to test whether the three-year life cycle of the salmon could be sustained in freshwater. If successful, returning fish would be captured to provide eggs and sperm for a permanent hatchery program.

On a gray, snowy April 2, 1966, the program officially launched. A state legislator used a ceremonial golden bucket to dump the first finger-sized Coho into the Platte River, which feeds Lake Michigan. Tanner himself stood at Bear Creek, worrying about the magnitude of the decision. He confessed to his wife, “I’m going to be either a hero or a bum,” noting the outcome would “reverberate for a long time”.

Tanner’s gamble paid off almost immediately. Coho typically spend 18 months in the ocean. However, some mature sexually faster. By September 1966, full-grown Coho “jacks” were returning to the planting streams. Western fisheries officials who visited Michigan were “flabbergasted” by this rapid success. They told Tanner to expect the major returns the next year.

The Salmon Craze Erupts

In the fall of 1967, as the alewife die-off waned, the first full class of Coho returned. The fish, gorging on the abundant alewives, were coming in “fat like footballs”. While an adult ocean Coho averages about 8 pounds (3.6 kg), Great Lakes specimens topped 20 pounds (9.1 kg).

A massive “salmon craze” immediately swept the region. Thousands of fishermen descended on the Lake Michigan shoreline. Wild-eyed steel mill workers were pulling in “lunkers” north of 20 pounds near Chicago. Motor builders like Evinrude began marketing special salmon boats. The Coho introduction triggered one of the greatest spikes in outboard motor sales in industry history.

The fever led to disaster on September 23, 1967. Thousands of anglers ignored small craft advisories and went miles out onto the lake in small boats. When a gale blew in, hundreds of boats were swamped. U.S. Coast Guard crews rescued dozens of people, but 7 fishermen died.

Tanner’s vision had instantly transformed the “forlorn waters” into one of the world’s most popular recreational fishing destinations.

Toxic Flesh and Perch Decline

The success was tempered by contamination. Biologists soon discovered that salmon flesh was packed with the pesticide DDT. Concentrations reached 19 parts per million, more than three times the federal limit of 5 parts per million.

Michigan officials scrapped a plan to commercially sell the excess salmon. However, sport anglers were allowed to continue catching and eating their fill. The DDT “scare” was reportedly of “little concern to the real fishermen”.

The introduction of Coho was quickly followed by Chinook salmon, which can grow even larger. Chinook plantings began to dominate the stocking programs. By the mid-1980s, Lake Michigan was being pumped with more than 10 million salmon annually. Federal lake trout plantings lagged at about half that volume.

The intensive management for the exotic species led officials to prioritize the invasive alewife. Wayne Tody concluded that the alewife was “as important to the future of the Great Lakes as any of its native species”. When alewife numbers dipped in the 1990s, Wisconsin banned commercial harvesting of them.

Meanwhile, native species like yellow perch suffered dramatically. Commercial fisherman Pete LeClair insisted that alewives devoured perch fry like a “herd of cattle”. Wisconsin banned commercial perch fishing on Lake Michigan in the mid-1990s, but the species has never fully recovered.

The Illusion of Control

A myth quickly grew that the salmon had eaten all the dead alewives off the beaches in 1968. Tanner allowed this myth to persist because it was “good publicity”. However, the actual number of salmon present in the lake that year was too small to make a significant dent in the alewife population. Tanner later clarified that he did not stock salmon to solve a beach problem. He was there to “build a fishery”.

Tanner likened his philosophy to a rancher who finds an island overgrown with grass (alewives). The rancher would not ask if cows (salmon) could shorten the grass. He would say, “My God, I can raise more beef than you ever saw in your life”. The states acted like ranchers, aggressively boosting hatchery plantings into the millions. By the late 1990s, over half a billion hatchery-raised Pacific salmon had been planted across all the Great Lakes.

The Inevitable Crash

The aggressive farming of the lakes proved unsustainable. Lake Huron was the first to suffer a devastating Chinook demise. The salmon population crashed so rapidly that biologists likened it to driving off a cliff. The average weight of adult Chinook in Lake Huron plummeted from over 14 pounds (6.4 kg) in the mid-1990s to barely 8 pounds (3.6 kg) by 2006.

This crash corresponded directly to a drop in the alewife population, the salmon’s favored food. That alewife drop, in turn, was tied to a 90 percent drop in phytoplankton, caused by new invaders. The exotic food web that Tanner built was highly fragile.

Howard Tanner’s initial plan was never to eliminate the alewives. He wanted them to be “alive and healthy,” serving as the permanent foundation of the fishery. Unfortunately, the ecosystem he engineered was a “biological flicker”—a brief several decades where humans achieved precise ecological results.

Today, the Upper Great Lakes are beginning a native species renaissance, primarily because the alewives are disappearing. Biologists argue that a true native fish recovery cannot be achieved “in the presence of alewives”.

Lake Michigan’s Uncertain Destiny

Lake Michigan remains more biologically productive than Lake Huron, supporting higher plankton and alewife counts. However, Lake Michigan fishery managers are now seeing alarming trends. Alewife numbers are at an all-time low, and older, larger alewives are disappearing. This is precisely what preceded the Lake Huron crash.

In an effort to stabilize the fishery, states bordering Lake Michigan drastically reduced stocking. Stocking levels dropped from a peak of 8 million Chinook annually in the late 1980s to about 1.8 million in 2016. State biologists are using techniques to imprint salmon with the scent of their concrete hatcheries, ensuring their return for egg harvest.

Biologists Nick Legler worries about the future. He monitors the system, hoping to keep it in balance. Tanner also remains concerned, noting Lake Michigan is “on the same course as Lake Huron”. Chuck Madenjian, a U.S. Geological Survey biologist, notes that the system is entirely synthetic. Nobody knows how long the mixture of Pacific salmon and Atlantic alewives can last.

The aggressive planting of salmon was a relatively simple fix for the alewife and lamprey crisis. However, the system is now facing a devastating new wave of biological invasions. This new chaos attacks the food web at the bottom, making solutions far more difficult than fixing the problem at the top. This third wave arrived as noxious cargo.