Lakes on the Line

The Great Lakes have made huge environmental gains during the past 50 years—but today, new challenges are roiling these vital waters

  • Drew YoungeDyke
  • Conservation
  • Jun 09, 2022

Minnesota native Jeff Schulte hoists a massive walleye he caught in Lake Erie near Ohio’s Ottawa County, now called “The Walleye Capital of the World.” Declared “dead” in the 1960s, Lake Erie revived thanks in part to protections mandated by the 1972 Clean Water Act. (Photo by Lee Thomas Kjos)

MINNESOTA NATIVE AND AVID ANGLER Jeff Schulte knows a thing or two about walleye, a sport fish native to the northern United States and Canada. “I’ve fished walleye my whole life, but nothing compares to walleyes in Lake Erie right now for size and abundance,” he says, crediting ample forage and healthy waters for the boon. “These fish are growing so fast, they’re just grotesquely chubby.”

This fish tale would have been unimaginable 50 years ago, when Lake Erie was a putrid dumping ground for pollutants. An article in MacLean’s magazine in 1965 titled “Death of a Great Lake” described it as a 10,000-square-mile dead sea: “By smothering it with pollution, man is making it an odorous, slime-covered graveyard.”

Prompted in part by such devastation, the U.S. Congress in 1972 passed the Clean Water Act to curb pollution and protect U.S. waters. Lake Erie’s resurrection is one of many success stories tied to that historic legislation. But today, rising human populations, a changing climate, invasive species and other threats are renewing concern for the nation’s waters—particularly for the five Great Lakes.

Read the Caption
A shoreline in Isle Royale National Park

Michigan’s Isle Royale National Park in Lake Superior (above) is a car-free wilderness where wildlife thrive. From protected parks to densely populated cities, millions of people depend on the Great Lakes (below) for survival. Covering more than 94,000 square miles, they hold 21 percent of Earth’s surface fresh water.

A global treasure

A map of the Great Lakes

The Great Lakes are epic waterscapes—freshwater inland seas with stunning shorelines, vital habitat for wildlife and waters that mean life itself for millions of people. Carved by glaciers and filled as they melted some 11,000 years ago, the lakes today span eight U.S. states and the province of Ontario, Canada. Lakes Ontario, Erie, Huron, Michigan and Superior and their connecting waters cover more than 94,000 square miles, hold 21 percent of Earth’s surface fresh water and drain a watershed that’s home to 34 million people. These waters are also home to the many Tribal nations with reserved treaty rights and a connection to the lakes that dates back millennia.

The Great Lakes region—which includes three national lakeshores and two national parks—is also a haven for wildlife. Moose, wolves, bears and a host of other terrestrial species thrive across the region, and the lakes support more than 170 species of fish, including salmon, trout, muskie, bass, pike, perch and the famous walleye. These fish in turn support a $7 billion annual sport fishery and some 75,000 jobs. But for all their collective majesty and cultural, economic and biological significance, the Great Lakes today are facing great challenges as significant as any in their history.

Read the Caption
Mussel and snail shells washed up on the shore of Lake Erie

Amidst the massive beauty of the Great Lakes, multiple challenges threaten the region’s health. Invasive quagga mussels (pictured) and zebra mussels now litter the lake beds, filtering out the phytoplankton native fish need to survive.

Unwelcome newcomers

“There is no greater ecological and economical threat to the Great Lakes than invasive species,” says Marc Smith, the National Wildlife Federation’s Great Lakes policy director. Invasive zebra and quagga mussels have been particularly destructive—and have spread at an alarming rate.

In the 1980s, zebra mussels entered the Great Lakes through ballast water discharges from overseas vessels, according to the U.S. Geological Survey. Native to Eurasian fresh waters, zebra mussels have had a devastating impact by displacing native mussels, clogging up water intake systems, carpeting lake beds in sharp points and filtering out algae that native aquatic organisms need for food.

Quagga mussels, native to the Black Sea region, arrived in the 1990s and have already largely displaced zebra mussels in lakes Ontario, Huron, Michigan and the eastern basin of Lake Erie. Like zebra mussels, they rapidly colonize lake beds and hard surfaces such as docks and water intakes and filter out the phytoplankton at the base of the aquatic food chain. This filtering turns the water crystal clear, signaling the loss of vital natural food sources—and that loss of food is already having a negative impact on some fish populations.

“Over the past decade, it’s been actually more difficult to catch fish” in Lake Michigan, says David Rose, a longtime fishing guide out of Traverse City, Michigan. “The nutrients just aren’t there, and the clarity actually makes it more difficult.” He faults invasive mussels for the decline.

With nutrients already depleted across much of the Great Lakes, the addition of a new invasive species that also feeds on phytoplankton and algae could be a nail in the lakes’ coffin—and that intruder is invasive carp. 

Originally imported into southern U.S. aquaculture facilities in the 1960s and 1970s, invasive carp—including bighead, silver, grass and black carp—have steadily advanced northward through the Mississippi River watershed after escaping into wild waters. Voracious feeders that can reach more than 100 pounds in size, invasive carp damage native aquatic ecosystems by consuming base-level food chain resources and rapidly reproducing. In some southern waters, they now occupy up to 90 percent of the aquatic biomass.

If these carp reach Lake Michigan, scientists estimate they would have enough food to spread throughout the Great Lakes and into connected inland lakes and rivers. With their food source depleted, native fish would decline, negatively impacting the sportfishing industry. And because schools of silver carp leap high out of the water when spooked by the sound of boats, they pose a physical threat to recreational boaters and their gear.

Following a decade of advocacy from NWF and other groups urging protections to keep invasive carp out of the Great Lakes, last year Congress authorized a plan to rebuild the Brandon Road Lock and Dam on the Des Plaines River about 50 miles south of Chicago. The project would involve installing a suite of smart technologies such as electric barriers, air-bubble curtains and acoustic deterrents to block the carp. Governors of states adjacent to the lakes are urging full federal funding of the $858 million project as soon as possible to help protect the Great Lakes from an invasive species that could have catastrophic consequences.

Read the Caption
Invasive silver carp jump out of a river

Several species of invasive carp are heading north toward the Great Lakes. These voracious feeders outcompete native fish, and their violent leaps as boats come near put anglers at risk.

When green isn’t good

While too few nutrients is a problem in Lake Michigan, too many nutrients is a summertime plague in the western basin of Lake Erie. In recent years, the region has suffered annual cyanobacterial algal blooms, sometimes with toxic microcystins. Bloom severity varies based on factors such as temperature and rainfall, but the main cause is the influx of nutrients—particularly phosphorus—from farm runoff, which causes algae to spread, consuming oxygen and blocking sunlight. In 2014, a toxic algal bloom caused a drinking water crisis in Toledo, Ohio, and these blooms regularly close beaches and create “dead zones” devoid of oxygen.

Though worse in recent years as temperatures warm, this is not a new problem. In 1972, the year the Clean Water Act passed, the United States and Canada signed the Great Lakes Water Quality Agreement setting a reduced target for phosphorus loads in the lake. Those reduced targets helped resurrect Lake Erie, but as algal blooms have been intensifying, the agreement’s goal of reducing 2008 phosphorus levels 40 percent by 2025 is unlikely to be reached.

To address problems plaguing Lake Erie, in 2019 Ohio Gov. Mike DeWine launched H2Ohio, an initiative to fund projects such as wetland restoration, nutrient monitoring and voluntary best management practices to reduce runoff. Time will tell whether such measures can meet reduction targets or whether stronger mandatory protections will be needed.

Read the Caption
A boat drives through a bright green algal bloom

Warming temperatures and agricultural runoff create massive harmful algal blooms (such as this one in Lake Erie in 2011).

The chemicals within

There’s a cruel irony in living next to a freshwater sea yet lacking clean water to drink, but that’s exactly what’s happening in Flint and Benton Harbor, Michigan, Chicago, Illinois, and several other Great Lakes communities—primarily communities of color—where lead levels are well above established limits due to aging infrastructure. In addition to the lead crisis, some lakes are tainted with harmful per- and polyfluoroalkyl (PFAS) chemicals, nicknamed “forever chemicals” because they don’t break down in the environment.

The Wurtsmith Air Force Base near the Michigan town of Oscoda on Lake Huron is one known source of PFAS. Before the base closed in 1993, it hosted fire-suppression training using foam that contained PFAS chemicals, which have been linked to infertility, cancer and other ills.

In 2010, PFAS contamination was discovered around Oscoda. It was so bad across from the former base in the Huron National Forest that the state issued a deer consumption advisory in 2018. The state has also issued fish consumption advisories, including along the Au Sable River, and residents have seen telltale PFAS foam washing up on the beach of a local playground. “The Oscoda community has worked for over a decade to bring attention to the PFAS contamination impacting their health, the health of their families and the natural resources that draw people to this special place along Lake Huron,” says Jennifer Hill, NWF’s Great Lakes associate director. Yet “a comprehensive cleanup plan is still not in place.”

Read the Caption
A bulldozer pushes dirt near Duluth Harbor

Changes in rainfall patterns have caused record lake-level rise in recent years, eroding shorelines. Dredging material to rebuild shorelines (such as this barrier island at Duluth Harbor Basin on Lake Superior) may contain hazardous wastes.

Weather’s uneven hand

As warmer temperatures contribute to algal blooms in the Great Lakes, changing precipitation and weather patterns are causing wild swings in water levels. Lake Superior has been hit by record high lake levels in recent years that have eroded shorelines and damaged infrastructure, particularly along Minnesota’s Duluth Harbor Basin, which lies protected within the largest barrier island in the Great Lakes. To mitigate erosion at the site, the U.S. Army Corps of Engineers is depositing dredging fill pulled from the harbor, which was once a major industrial shipping port for iron. Glass, shards of aluminum and taconite pellets have been found in the fill, posing a threat to people and wildlife. “Potential other harmful chemicals in the dredge spoil may present more of a threat to aquatic life,” says Brad Gausman, executive director of the Minnesota Conservation Federation, an NWF affiliate. “Utilizing dredge material from a historically industrial harbor is an inappropriate response that does not truly address the underlying problem and may exacerbate other challenges created by a warmer climate.”

Read the Caption
A moose wading in mist covered water

A moose wades along the shores of Isle Royale National Park. Ensuring a healthy future for the entire Great Lakes ecosystem will sustain wildlife—and human life—for generations to come.

A hidden peril and public resolve

Lake Huron meets Lake Michigan at the Straits of Mackinac, where the currents of the lakes crash into each other beneath the Mackinac Bridge—and into Enbridge Energy’s 69-year-old Line 5 twin pipelines, which pump nearly 23 million gallons of oil and natural gas liquids through the Straits on top of the lake bed. After a disastrous 2010 spill from a different Enbridge pipeline sent more than 840,000 gallons of crude oil into Michigan’s Talmadge Creek and Kalamazoo River, NWF and other environmental groups began taking a closer look at Line 5. They discovered a history of more than 33 inland spills since 1968 totaling more than 1 million gallons as well as structural problems such as missing supports and dents from multiple anchor strikes. 

Though Enbridge in 2018 agreed to eventually replace the pipelines with a tunnel underneath the straits, the timeline for this action keeps moving into the future, and Enbridge has refused to be fully transparent about risk, including the risk of explosion during construction and operation. And though Michigan Gov. Gretchen Whitmer revoked Enbridge’s easement effective in May 2021, the company is still illegally operating the pipeline, prompting court battles at the state and federal levels.

Last fall, leaders of Michigan’s 12 federally recognized Tribal nations sent a letter to the Biden administration asking it to support the shutdown of Line 5. “Our people—the Anishinaabe—have a teaching that the decisions we make today should result in a sustainable world seven generations into the future,” they wrote. “[T]he decisions we make ... will have consequences long after we are gone.”

A 2021 International Joint Commission Great Lakes Regional Poll found that more than 90 percent of residents in the region agree it’s important to protect the health of the Great Lakes, and help may now be on the way. The 2021 infrastructure bill contained a $1 billion increase to the Great Lakes Restoration Initiative, spread over five years. This is in addition to an increase in the Great Lakes Restoration Initiative Act of 2019, which boosts annual funding levels from $300 million to $475 million over five years.

Clearly the public supports Great Lakes protections, and Congress has responded with bipartisan efforts to fund them. But today’s complex challenges cannot be solved solely with money or one sweeping piece of legislation. They require constant vigilance of environmental organizations, continued bipartisan commitment to protections, ongoing dedication of Tribal nations, scientific research to understand the issues and the united support of each individual in awe of the greatest freshwater resource in the world.


Saving the Great Lakes

The National Wildlife Federation’s Great Lakes Regional Center was established in 1982 through a partnership with the environmental legal clinic at the University of Michigan Law School. The Federation’s work in the region includes policy advocacy, habitat restoration and co-leading and staffing the Healing Our Waters–Great Lakes Coalition. “We are committed to building coalitions with our partners to ensure that our water and vast natural resources remain healthy and accessible for all people,” says Mike Shriberg, NWF’s Great Lakes regional executive director. “Partnering with hunters and anglers, frontline communities, business leaders, farmers and environmentalists, we strive to conduct all our work through a lens of equity and justice.”

Drew YoungeDyke is NWF’s director of conservation partnerships in the Great Lakes Regional Center.

More from National Wildlife magazine and the National Wildlife Federation:

Our Work: Protecting the Great Lakes »
Great Lakes Conservation Coalition »
Historic $1 Billion in Great Lakes Restoration Investments Will Secure Critical Ecosystem for People, Wildlife »

Get Involved

Where We Work

More than one-third of U.S. fish and wildlife species are at risk of extinction in the coming decades. We're on the ground in seven regions across the country, collaborating with 52 state and territory affiliates to reverse the crisis and ensure wildlife thrive.

Learn More
Regional Centers and Affiliates