Alien Invaders from Outer (Aquatic) Space Part 2
There was an old lady who swallowed a salmon…
“The Great Lakes is one of the most invaded aquatic ecosystems in the world.”—Derek P. Crane and Donald W. Einhouse in the Journal of Great Lake Research
Part one of this series explained how the construction of the Welland Canal in 1919, which allowed commercial ships to get around Niagara Falls, opened the Great Lakes to waves of devastating invasive species, including sea lampreys and alewives.
A Great Lakes Savior
Decades of pollution, overfishing, habitat loss, and now invasive species had brought Lake Erie, and all the other Great Lakes, to the brink of collapse. By the mid-1960s, alewives were just about the only fish remaining—estimates suggest they accounted for up to 90% of the biomass in the Great Lakes at that time. While these small herrings had conquered the ecosystem, they were poorly adapted to its temperature swings. Billions of them would die at a time, their rotting corpses clogging municipal water intakes and piling up all over beaches in Ohio, Michigan, Illinois, and Wisconsin. In 1964, Howard Tanner accepted a job as fisheries chief in his natal state of Michigan, a choice that would prove fortuitous for the Great Lakes’ ecosystems and their recreational fishing culture.
Tanner returned to the Midwest after more than a decade working in Colorado and brought with him a novel approach to managing fish populations. Tanner described the clear direction he got on starting this new position to Boating Magazine: “My new boss (Michigan Conservation Department director Ralph MacMullan) was a profane man. In my first conversation with him, he told me, ‘Fisheries Division hasn’t done a God-damned thing in 40 years. I want you to do something.’ And, as I walked out the door, he said, ‘and if you can, make it spectacular.’”
Tanner’s story is long and fascinating—you should read the book about it—but I’ll cut to the punchline: Tanner decided to import Pacific salmon from West Coast hatcheries and release them into America’s inland seas. No one was sure if this idea was going to work, but everyone agreed they had to try something.
According to a report, Tanner wrote: “The ultimate aim is to convert an estimated annual production of 200 million pounds of low-value fishes—mainly alewives—that now teem in the upper Great Lakes into an abundance of sport fishes for recreational fishermen.”
Technically, salmon had made that trip before, but Tanners were the first to succeed.
His stocking plan was better targeted, more robust, and sustained over a longer period. Plus, the salmon that he brought over were being released into a system now teeming with alewives, which the salmon quickly started devouring.
A New Fishery Is Born
Two years after the first juvenile coho salmon were introduced into Lake Michigan, they returned to the rivers where they had been planted by the tens of thousands, and they were huge. Midwestern anglers had never seen anything like it: hordes of fat, hard-fighting fish suddenly appeared in their waters, and because the salmon were running back to where they had “spawned,” they were accessible to even casual anglers with minimal gear.
Tanner described the scene as, “a frenzy:”
“With existing tackle and small boats and motors, they went out and they caught their load of five fish, and their lines got busted, and the fish were leaping out of the water, and they were all around them, and the excitement was just explosive.”
Other Great Lakes states took notice and followed suit. By the early 1970s, all the Lakes, including Erie, were stocking some mix of coho, chinook, and pink salmon. A new salmon fishing culture, and industry, emerged. Before Pacific salmon, the Great Lakes didn’t really have a recreational fishing culture. People fished, but sparsely and mostly for panfish. Even before lake trout disappeared, they weren’t sport fish. They tend to frequent very deep water, which makes catching them consistently difficult for the average weekend warrior. All of a sudden, the Great Lakes were bursting with silver rocketships that smashed lures and baits, peeled drag, leaped from the water, and made for great table fare. American fishing changed, as did our relationship with the Great Lakes.
“I always point out that we created a constituency for the lakes,” Tanner told the Milwaukee Sentinel Journal.
The salmon brought recreational fishing to the Great Lakes, which meant that huge numbers of Americans were personally invested in the status and health of those fisheries, both because they wanted to keep catching fish there, and because they wanted to feel confident that the fish they fed their families were safe.
Voracious Eating Machines
Journalist Dan Egan described Pacific salmon as, “essentially swimming muscles that…feed with such ferocity that they can grow to 40 pounds [in the Great Lakes] during their three-year life cycle. It can take a lumbering lake trout 40 or 50 years to reach that weight, carrying much of it as belly fat.”
During the 1980s the Great Lakes, especially Michigan and Huron, became “an angler playground.” Fisheries managers stocked tens of millions of non-native salmon and trout annually, which in turn feasted on the non-native alewives. The planted salmonids proved perfect predators. So much so that they quickly consumed most of their forage base and began starving. By the early 1990s annual catch rates for chinook salmon dropped 85% from their peak.
Anglers and resource managers had a new problem: The salmon fishery they had created in the Great Lakes became so popular—and economically important to local communities—the once reviled alewives were now viewed as an essential resource. Without alewives, there are no salmon, and salmon and trout make up 70%-80% of the recreational fishing in the Great Lakes.
Today, Lake Michigan is the only Great Lake that sustains significant Pacific salmon populations, though salmon still swim—and get caught—in Huron, Superior, Ontario, and even Erie. Alewife populations are now controlled, and native fish like lake trout and yellow perch have seen significant comebacks.
A Permanent Shift
Though the salmon bonanza was short-lived in many of the Great Lakes, its impact on recreational fishing, fisheries management, and anglers’ relationships with the Lakes has persisted and evolved. Even Lake Erie, which never sustained a significant population of Pacific salmon, has benefitted from this shift. Erie’s massive walleye rebound, which started in the ‘80s and persists today, has helped keep alewife numbers down, though the invasive herring maintain a population there.
The meteoric jump in recreational fishing across the upper Midwest that followed salmon introduction helped create the culture and infrastructure we now enjoy. Gazing out at a crowded spring Maumee River or walking along a bustling charter dock in Port Clinton today, it’s difficult to imagine that fishing for fun is relatively new here. Just a couple of generations ago, before Tanner brought salmon across the continent, the Great Lakes were not fishing destinations.
In many ways, everyone drawn here by that compelling tug owes a debt to invasive species. Those salmon built the connection we all now cherish and perhaps take for granted, whether we’re trolling for chinooks, jigging for perch, ice fishing for whitefish, fly fishing for steelhead, or casting for musky. The salmon brought in the anglers and made room in the system for native fish to rebound.
In the next and final installment of this series, we cover the newest waves of invasives to arrive in Erie and imagine what might happen in the future.