Forest Keepers
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Living Landscape At high tide, the marshes in Mobjack Bay, near Hayes, Virginia, fill with salt water. Areas like this offer rich habitat and foraging grounds for Chesapeake Bay’s marine animals, including birds, fish and crabs. © Cameron Davidson
Stephanie Alexander stands on a wooden platform two stories high and peers over the edge of a steel tank into a pool of murky water. The manager of Horn Point Oyster Hatchery, one of the largest oyster hatcheries on the Eastern Seaboard, can’t see them with the naked eye, but she knows they’re there: millions of oyster larvae fattening up in a 10,000-gallon tank.
“These guys are only nine days old,” she says.
They’ll remain here, feasting on specially grown algae, for another week or two, then move into outdoor tanks containing oyster shells. The larvae will attach to the shells—at which point they’re called “spat”—and acclimate to the outdoors before being dumped from a barge into the waters of the Chesapeake Bay. Over the last decade, Horn Point, run by the University of Maryland Center for Environmental Science, has been the birthplace for billions of oysters released into the bay, part of a multistate restoration effort to help clean up the United States’ largest estuary.
Oyster Production
Stephanie Alexander, Senior Faculty Research Assistant, at Horn Point Hatchery in Cambridge, Md. cleans an oyster larvae tank. Larvae are nurtured into spat on shell, which will eventually be placed into the Chesapeake Bay and supplied to oyster farms.
© Greg Kahn
Oysters
At the Horn Point Oyster Hatchery oysters are spawned in water-filled tanks as part of a large-scale effort to supply oyster farms and restoration efforts in the Chesapeake Bay. The hatchery is one of the largest on the East Coast.
© Greg Kahn
Oyster Production
Stephanie Alexander, Senior Faculty Research Assistant, at Horn Point Hatchery in Cambridge, Md. cleans an oyster larvae tank. Larvae are nurtured into spat on shell, which will eventually be placed into the Chesapeake Bay and supplied to oyster farms.
© Greg Kahn
Oysters
At the Horn Point Oyster Hatchery oysters are spawned in water-filled tanks as part of a large-scale effort to supply oyster farms and restoration efforts in the Chesapeake Bay. The hatchery is one of the largest on the East Coast.
© Greg Kahn
James “Bubba” Parker of Choptank Oyster Company harvests oysters from floating baskets off the company’s pier in Cambridge, Md., on Oct. 21, 2024. Choptank Oyster Company is known for its sustainable aquaculture practices, producing high-quality oysters for the region while supporting the health of the Chesapeake Bay. The company’s oysters are grown in floating baskets, a method that allows for optimal water flow and growth conditions. By helping to filter and clean the bay’s waters, the farm plays a vital role in the restoration of oyster populations in the Chesapeake, which are crucial for maintaining the bay’s ecosystem.
The Chesapeake Bay covers almost 4,500 square miles and is home to more than 3,600 species. It’s a nursery for fish that may later swim as far away as Maine, and the bay itself produces half a billion pounds of seafood each year, including the region’s beloved blue crab. It’s been the outdoor playground for generations who vacation on its beaches, boat on its waters and watch the sunset from its shorelines. Its watershed filters drinking water for nearly 13 million people.
The Chesapeake is also surprisingly vulnerable. It’s shallow, averaging just 21 feet, which makes it especially susceptible to water pollution. The bay’s oyster reefs were once so dense and numerous that they hindered ship navigation. Sturgeon, rays, rockfish, crabs and more filled the waters, using the bay’s dense seagrasses as protective nurseries.
But a lot has changed in the last 400 years. Throughout its watershed, forests—crucial for ensuring water quality—were felled for logging, agriculture and development. Fish and oysters were overharvested. Algal blooms created dead zones and blocked sunlight in the water column, which caused seagrass meadows to die off. And the region’s human population boomed to more than 18 million, bringing roads, parking lots, sprawling subdivisions and pollution.
Since the 1980s, however, state governments, federal agencies and hundreds of nonprofits, including The Nature Conservancy, have fought to restore the Chesapeake—if not to what it once was, at least to a sustainable and healthier bay.
“To get clean water in a place as big as the Chesapeake, someone has to be working everywhere,” says Mark Bryer, TNC’s Northeast Division director.
This group effort has created oyster sanctuaries, restored tracts of forests, brought seagrass meadows back to life, and worked with farmers and cities to reduce water pollution. They are making real progress—but there’s a long way to go.
“If we can’t figure this out in the Chesapeake, we’re in trouble,” says Amy Jacobs, the director of TNC’s Chesapeake Bay Program. Many of the bay’s greatest challenges, after all, also threaten the Mississippi River and the Gulf Coast, as well as other critically important bodies of water. “But I think it’s a great experiment for the world,” she says. “How do we figure this out? What can we do to be successful?”
To begin to answer those questions, you have to go north.
Quote: Mark Bryer
To get clean water in a place as big as the Chesapeake, someone has to be working everywhere.
Northeast Division Director
As the sun rises fog lifts from Pine Creek Gorge in northern Pennsylvania on Oct. 19, 2024, revealing the dramatic landscape of what is often called the “Grand Canyon of Pennsylvania.” Located within the Tioga State Forest, this 47-mile-long gorge reaches depths of up to 1,450 feet and offers stunning views of rugged cliffs and dense forests. Carved over millions of years by Pine Creek, the gorge plays a crucial role in the watershed, as its waters ultimately flow into the Susquehanna River, one of the largest tributaries to the Chesapeake Bay. This region is a vital part of the broader ecosystem, contributing to the health of the bay.
An early April fog has set in on Hamer Woodlands at Cove Mountain, a tract of land along the Kittatinny Ridge near Harrisburg, Pennsylvania. Goldfinches and a variety of woodpeckers pierce the silence. Hundreds of tadpoles vibrate in a vernal pool. A hiking path leads to a steep clearing and offers views of the Susquehanna River stretching out far below.
“The Appalachians here are a series of parallel ridges that run [through] Pennsylvania, and the Susquehanna snakes through them,” says Keith Fisher from his office 10 minutes south. He is TNC’s conservation director in Pennsylvania and Delaware. “Our work here is about giving the water a place to start.”
A map of the Chesapeake Bay watershed for the 3-25 issue of the magazine. The Chesapeake Bay receives fresh water from a vast watershed spanning 64,000 square miles across six states and the District of Columbia, including some of the most densely populated areas of the country. Since the 1980s, the states and D.C. have made agreements to reduce pollution that reaches the bay.
Did You Know?
At one point in time, today’s Chesapeake Bay functioned as the river valley of the Susquehanna River. About 35 million years ago, an asteroid or some other object from space hit the region near where the present-day Bay meets the Atlantic Ocean, creating a large and deep impact crater. This event caused a huge tsunami, which helped shape the future development of the Chesapeake Bay. Read more about the ongoing research into this event and the evidence researchers are still discovering today of the asteroid’s impact on the region’s geology at Cool Green Science.
As large as the Chesapeake Bay is, its watershed is much larger. It traverses the southern border of New York, parts of West Virginia and east to the coastal Delmarva Peninsula, covering parts of six states and Washington, D.C. About 150 rivers flow into the bay. Among them, the Susquehanna is king: It provides about half of the fresh water that runs into the Chesapeake each year.
The Nature Conservancy bought Hamer Woodlands’ 1,379 acres in two parcels in 2017 and 2021, filling a gap in an otherwise continuous 14-mile stretch of protected lands along the Kittatinny Ridge. A few years before creating the preserve, TNC began working with Capital Region Water, the area’s water agency, to help sustainably manage a stretch of forested land just across the river from the preserve. It’s the type of work, Fisher says, that they’re doing throughout the state—working with landowners, land trusts and the American Forest Foundation, a national conservation group, to preserve land that was historically forested. Similar work is happening in Virginia, where TNC bought 700 acres of forest near the James River in April 2025.
“Forests provide clean water,” Fisher says. “They capture the water. They store it. They release it slowly into streams. It’s natural filtration.”
Today less than 60% of the Chesapeake’s watershed is forested, but at one time, that number was closer to 95%. The landscape was wetter, too. In the 1980s, a Johns Hopkins paleoecologist named Grace Brush used soil cores taken from around the watershed to create a picture of what the area once looked like. Beavers, she wrote at the time—possibly numbering in the millions—constructed dams that held fresh water longer on the landscape. This slowing down of the fresh water made the bay saltier, and in response salt-loving oysters thrived much higher in the tributary rivers—filtering water before it reached the Chesapeake. In fact, there are still remnants of long-lost oyster reefs in Baltimore Harbor. It’s just one way changing the forests has changed the bay itself.
Recently migrated Canada geese search for food in the marshes of Blackwater National Wildlife Refuge on Nov. 16, 2024. Located on Maryland’s Eastern Shore, the refuge is a vital sanctuary within the Chesapeake Bay watershed, providing critical habitat for migratory birds and other wildlife. Spanning over 28,000 acres, Blackwater is known for its extensive tidal marshes, freshwater ponds, and diverse ecosystems that support species like bald eagles, Delmarva fox squirrels, and waterfowl during the winter months.
In the 1970s, the Chesapeake Bay reached its crisis point. Fish populations—critical to the region’s seafood industry—were crashing, and tens of thousands of acres of seagrasses had died off. Politicians and the newly created Environmental Protection Agency also wanted to know what was happening.
“When we started out there were six or seven ideas about what was causing the seagrass decline,” says Walter Boynton, one of the ecologists tasked with solving the mystery in the 1970s. Today, Boynton is a trustee of The Nature Conservancy in Maryland and a professor emeritus at the University of Maryland Center for Environmental Science.
In what became groundbreaking research, the team showed that an excess of nitrogen and phosphorus from common fertilizers was the culprit. These nutrients were running off farm fields and developed areas and seeping into tributaries. When they reached the bay, they fed algae, making the water cloudier, and promoted the growth of tiny organisms called epiphytes, which clung to seagrass so densely that sunlight couldn’t penetrate.
Spurred in part by this research, the governors of Maryland, Virginia and Pennsylvania in 1983 signed the Chesapeake Bay Agreement, a commitment to clean up the bay. The framework set a precedent, and over the decades multiple agreements followed, with Washington, D.C., West Virginia, New York and Delaware signing on as well. In 2010, the EPA placed limits on Chesapeake Bay pollution, making the states’ previously voluntary compliance more legally enforceable.
The water pollution comes from many upstream sources: wastewater, septic systems, agriculture, urban runoff and even a bit from air pollution. Stormwater runoff from urban and suburban areas is the only growing source of nutrient pollution in the bay, but agriculture still accounts for approximately 46% of nitrogen runoff, making it by far the largest contributor.
“We know we’re 37 million pounds a year short of meeting the 2025 goals for nitrogen reduction for the bay,” says Matt Houser, a sociologist with TNC and the University of Maryland Center for Environmental Science, who develops farmer engagement programs. The states’ plans to meet their nutrient reduction goals rely on the agriculture sector to make the largest contributions. “But farmers have made an incredible amount of progress.”
Farms along the north shore of the Susquehanna River in Pennsylvania between the Maryland Border and Conestoga, PA
Farmers working across 100,000 acres have joined the Mid-Atlantic 4R Nutrient Stewardship Association, an industry-led group launched in 2017. The 4R framework promotes more precise use of fertilizer: the right nutrient source, at the right rate, at the right time and in the right place.
“You want to ‘spoon-feed’ your crops over the growing season,” explains Kristin Fisher, a TNC applied agricultural scientist. Providing too much fertilizer leaves excess nutrients in the soil, which can become runoff into the bay.
In Maryland, about 50% of farmers now use legumes, rye grass or other cover crops to hold their fields’ soil in place during fallow seasons. These crops absorb nitrogen and release it back into soil when they’re killed off in the spring, potentially reducing the amount of fertilizers needed.
With 83,000 farmers working across the watershed—and a changing climate bringing heavier rains—the work can be a challenge, Houser says. Still, by working to make improvements in areas like agriculture, cities and oyster reefs, the coalition of nonprofits and agencies has managed to reduce annual nitrogen pollution by approximately 15% since 2009, which is 59% of the 2025 goal.
There’s reason to believe that if enough nitrogen and phosphorus are kept out of the bay, parts of the Chesapeake will recover shockingly quickly, says Walter Boynton. In the late 1990s, an underwater grass meadow near the mouth of the Susquehanna was almost gone before a drought hit the region, driving down nitrogen and phosphorus loads.
“That grass community, in just four years, went from almost nonexistent to covering 14,000 acres,” Boynton says. “It was so thick it was hard to move a boat through it, and so biologically active that it actually changed the quality of the water coming out of the Susquehanna. We do not need to wait many decades for rejuvenation.”
Shellfish on the Menu
Toni Lopes and Mak Davis prepare and serve Chesapeake oysters at Dylan’s Oyster Cellar in Baltimore. Commercial seafood in Maryland and Virginia is a $2.8 billion industry, and the bay annually produces about 500 million pounds of seafood. But catches can be halted during times of poor water quality.
© Greg Kahn
A Cleaner Bay
Members of crew teams after practice at the Potomac Boat Club in Washington, D.C. Many cities in the region are capturing and treating urban stormwater runoff. Stormwater is the only increasing source of nutrient pollution in the bay and a challenge, given population growth within the watershed.
© Greg Kahn
Shellfish on the Menu
Toni Lopes and Mak Davis prepare and serve Chesapeake oysters at Dylan’s Oyster Cellar in Baltimore. Commercial seafood in Maryland and Virginia is a $2.8 billion industry, and the bay annually produces about 500 million pounds of seafood. But catches can be halted during times of poor water quality.
© Greg Kahn
A Cleaner Bay
Members of crew teams after practice at the Potomac Boat Club in Washington, D.C. Many cities in the region are capturing and treating urban stormwater runoff. Stormwater is the only increasing source of nutrient pollution in the bay and a challenge, given population growth within the watershed.
© Greg Kahn
Back at Horn Point Oyster Hatchery, on the Delmarva Peninsula’s Choptank River, there’s a room with large glass jars and the sound of percolating water. Some jars are full of brown liquid; others are electric green. This is the algae room, Alexander says. The team will use a curated mix of these algae to feed the growing oyster larvae.
James “Bubba” Parker of Choptank Oyster Company harvests oysters from floating baskets off the company’s pier in Cambridge, Md., on Oct. 21, 2024. Choptank Oyster Company is known for its sustainable aquaculture practices, producing high-quality oysters for the region while supporting the health of the Chesapeake Bay. The company’s oysters are grown in floating baskets, a method that allows for optimal water flow and growth conditions. By helping to filter and clean the bay’s waters, the farm plays a vital role in the restoration of oyster populations in the Chesapeake, which are crucial for maintaining the bay’s ecosystem.
“Oysters are really good at filtering in anything,” she says. “They’re little vacuum cleaners.”
Like the seagrass meadows at Susquehanna Flats, oysters—when healthy and prolific enough—can improve the water quality around them, and their reefs provide critical habitat for other marine life.
In the last Chesapeake Bay Watershed Agreement, in 2014, Maryland and Virginia committed to restoring oyster reefs and ensuring their protection in 10 tributaries. They’re nearly done, and Maryland just signed up to do three more.
Piankatank River, Oyster Reef construction project on July 13th, 2023
The first project took place not far from Horn Point, at a sanctuary called Harris Creek, where 2 billion oysters were loaded onto the sanctuary’s numerous small reefs. When the construction phase was completed in 2015, it began one of the largest oyster restorations in the world—a wider network of reefs throughout the Chesapeake Bay that would ultimately total 2,300 acres.
“The goal is to have the sanctuaries kick-start everything else, and they’re doing a beautiful job of it,” Alexander says. The Maryland Department of Natural Resources monitored the reef three years and six years after the restoration and they found that 98% of the restored reefs in the Harris Creek Sanctuary still hosted thriving oyster colonies. The department declared the tributary to be restored.
“In Harris Creek you see spat sets, you saw water quality improve. You saw [underwater vegetation like seagrasses] rebound,” Alexander says. “Why? Because they’re filtering all the stuff out of the water column.”
Since 2014, nearly 7 billion spat-on-shell oysters have been placed in the bay, helping to double the population from a decade ago. All told, oyster reefs cover only 2% of their historic range, but there are signs that the offspring of planted oysters are already moving into new territories. Commercial fishers, Alexander says, have reported seeing them in nearby Broad Creek. She thinks larvae from Harris Creek have traveled there to set.
Emerging ghost forests at Blackwater National Wildlife Refuge on Nov. 16, 2024. Located on Maryland’s Eastern Shore, the refuge is a vital sanctuary within the Chesapeake Bay watershed, providing critical habitat for migratory birds and other wildlife. Spanning over 28,000 acres, Blackwater is known for its extensive tidal marshes, freshwater ponds, and diverse ecosystems that support species like bald eagles, Delmarva fox squirrels, and waterfowl during the winter months.
Returning the Bay to what it was in the 1600s is probably not possible, says Bryer, the Northeast Division director and former head of TNC’s Chesapeake Bay program. Too much has changed—the human population and resulting development across the region isn’t what it was then, for one. But the climate has changed, too.
Not far from Horn Point, on a quiet April morning, the ospreys are nesting at Blackwater National Wildlife Refuge. Over the years, TNC has helped to add about 5,000 acres to this sanctuary on the bay’s Eastern Shore, a mix of tidal marsh, freshwater wetlands and something called ghost forests. Gray, sun-bleached tree trunks mark the remnants of a woodland that became inundated by salt water. It’s a common sight on the Eastern Seaboard where the ocean is rising, and where more chaotic weather has resulted in fewer but heavier rains.
“We’re seeing a lot of marsh migration and saltwater intrusion around the Delmarva,” says Chase Colmorgen, a biologist with the conservation group Ducks Unlimited. Colmorgen works with TNC, Natural Resources Conservation Service (NRCS) and more to help landowners restore wetlands under a project called the Delmarva Wetlands Partnership. “We’re starting to lose other wetlands that way,” he says, adding that it’s not yet clear whether proactive restoration can keep up with rising sea levels.
Scientists here are asking hard questions about how to restore the bay, while also planning for a different future.
“The Chesapeake Bay, or any big ecosystem, didn’t get to the state that it’s in today in a decade or two,” Bryer says. “There is a history. There is a human history. And so the question is, ‘What do we want of it now? And what are we capable of?’ … We want to have a livable, swimmable, fishable bay.” And that, conservationists say, is possible.
In downtown Annapolis, visitors flock to Ego Alley, a narrow waterway that connects Annapolis Harbor to the heart of the city’s bustling historic district. The marina is lined with restaurants, shops, and venues for live events, creating a lively atmosphere where the charm of the waterfront meets the vibrancy of downtown. Boaters parade their vessels along Ego Alley, where they can experience the best of both worlds—immersed in the maritime culture while still part of the city’s lively scene. Annapolis Harbor itself has been a critical maritime hub for centuries, reflecting the city’s rich naval history as home to the U.S. Naval Academy and the annual Annapolis Boat Shows, one of the largest in the country.
The Chesapeake has come a long way, but there’s work left to do. While the latest Watershed Agreement ends in 2025, the states plan to continue with a similar framework. Meanwhile, however, the future of federal funding and commitment to the Clean Water Act and the Clean Air Act—which underpin much of the EPA’s work here—is in question. There’s also concern about the future of staffing at federal agencies that the coalition of Chesapeake Bay-area nonprofits have relied on as partners for decades.
Sustaining interest and investment in the bay has always been a key challenge, says Bryer. “It took a few hundred years of us doing lots of dumb things, and it won’t get better overnight.”
But Walter Boynton, decades after first investigating those lost seagrasses, isn’t daunted. Seagrasses—harbingers of so much of the bay’s decline—are now three times more extensive than they were 40 years ago. The dead zones have shrunk in size and last for shorter durations. Across the watershed, nitrogen pollution going into the bay has fallen by nearly a third and phosphorus levels are less than half of what they were in 1985—even as the population increased by roughly a third. And the blue crab, an icon of the region, has reached stable levels.
“We might not get to whatever the baseline was,” says Jacobs. “But there are places that have been restored and the biodiversity has returned. That tells me, if you build it, the wildlife will come, the biodiversity will come. And that gives me hope.”
About the Creators
Jenny Rogers is a senior editor and writer for Nature Conservancy, based near Washington, D.C. She recently covered sea turtle conservation for the magazine.
Greg Kahn is a photographer based near Washington, D.C. He previously covered the city’s efforts to clean up stormwater pollution for Nature Conservancy.
Cameron Davidson is an aerial photographer based in Virginia. His work has been published in National Geographic, Wired, Vanity Fair and more.
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