CONNECTICUT AND NEW YORK (May 20, 2026)—The Long Island Sound Partnership has released its 2026 forecast for hypoxia in Long Island Sound, projecting another year of relatively limited levels of low-oxygen conditions in the Sound’s bottom waters.
Hypoxia, in Long Island Sound defined as dissolved oxygen levels below 3 milligrams per Liter, is expected to affect a maximum of 15 square miles during the peak summer period. The highest extent is likely to occur around August 2, with a projected range between 8 and 23 square miles.
If realized, the 2026 forecast would represent a modest improvement over 2025 conditions, when hypoxia covered approximately 18 square miles at its peak, the smallest extent recorded since monitoring began in 1987.
“This year’s hypoxia forecast shows Long Island Sound’s water quality is on the right track and that the years-long trend of improvement will continue, building on last year’s historic progress,” said EPA Region 2 Administrator Michael Martucci. “Better oxygen levels mean a healthier Sound, and a healthy Sound benefits people and drives local economies all along its shores.”
“We are seeing improvements in the health of Long Island Sound over time, and these forecasts help us track how the Sound is responding to our ongoing joint efforts,” said EPA New England Regional Administrator Mark Sanborn. “Together with our partners, we are continuing to make progress in improving the health of the Sound and the economies and communities that rely on it.”
The 2026 forecasted hypoxic area is 89 percent smaller than the average extent observed between 1993 and 2009, reflecting long-term reductions in nitrogen loading to the Sound. Excess nitrogen fuels the growth of algae, and oxygen in the water is consumed as the algae die and decompose. Over the past several decades, improvements to wastewater treatment facilities and septic systems have reduced nitrogen loading to Long Island Sound by 65 percent compared to the baseline established in 2000, helping decrease the severity and extent of hypoxia.
Despite this progress, hypoxia levels can vary significantly from year to year, with observed conditions often fluctuating by as much as plus or minus 50 percent of the predicted extent based on environmental conditions.
“Year to year variation is expected when it comes to hypoxia in Long Island Sound,” said James Ammerman, environmental analysist with NEIWPCC and Long Island Sound Partnership Science Coordinator. “While reducing nitrogen is key, and something we can directly manage, other factors such as water temperature, rainfall, wind, and storm activity can also influence how hypoxia develops each year. Even with that variability, long-term trends show how the Sound is getting healthier, and reducing nutrient inputs remains the most effective way to lower the risk of more severe hypoxia over time.”
A key question for 2026 is whether hypoxia will be as limited as it was in 2025. Based on long-term observations and model results, scientists who worked on the forecast suggest conditions could be similar or even slightly improved this year. However, after several years of declining hypoxia, a modest rebound toward slightly more hypoxia is also possible.
The 2025 Year in Review highlights key projects and accomplishments from the Long Island Sound Partnership. This issue celebrates the Partnership’s 40th anniversary, introduces a new Comprehensive Conservation and Management Plan, and showcases progress across its four core goals.
Spring is in full swing, and May brings even more ways to get outside and support Long Island Sound. Read the Volunteer Newsletter: May 2026 to find upcoming volunteer and citizen science opportunities near you, including featured events celebrating Long Island Sound Day.
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Watersheds are also called drainage basins, and everyone lives in one. The water that runs off your yard or driveway, or flows from nearby streams, eventually reaches a specific destination.
The Long Island Sound watershed span six states and even reaches into Canada. Nearly all of Connecticut lies within it, along with parts of New York, Rhode Island, Massachusetts, New Hampshire, and Vermont. Together, nearly nine million people live within the LIS watershed, including more than four million within the coastal boundary. The exact total is 8,940,304, according to the 2020 US Census.
It’s the area of land that directly borders Long Island Sound. The coastal boundary is a planning line used by states to manage and protect coastal areas. It includes the shoreline and nearby inland places that affect coastal waters.
If you live in the Long Island Sound watershed, your actions can still impact the Sound, even if you’re outside the official coastal boundary.
Everything that happens on land affects the water that drains through it. The way we care for our lawns, the number of farms and factories, and even the amount of forested land all influence the health of Long Island Sound.
Excess nutrients, such as nitrogen and phosphorus, enter the watershed through fertilizers, wastewater, or septic systems. These nutrients can cause algal blooms and lead to low oxygen “dead zones.”
Pollutants, including heavy metals, pesticides, and PFAS, can enter the water if they are disposed of improperly.
Trash and plastics can travel through waterways and end up in Long Island Sound. The closer you live to the coast, the greater your impact on the Sound. But everyone in the watershed, no matter how far inland, plays a role in its health.
The Long Island Sound coastal boundary is based on natural features like climate, land shape, and water flow, along with political boundaries. It is defined differently in Connecticut and New York.
In Connecticut, the boundary follows an ecological zone called the coastal hardwoods. This reflects how far inland coastal conditions (like salt influence and climate) affect plant life.
In New York, the boundary is based more on geology and water movement. It follows the Harbor Hill moraine across Long Island, which separates groundwater that flows north into Long Island Sound. In the western part of the region, the boundary follows major landmarks like the Robert F. Kennedy Bridge and the Hutchinson River Parkway in Westchester.
The boundary is not fixed. It can change over time based on new science, environmental changes such as sea level rise, and management decisions that support water quality and habitat protection. The coastal boundary was most recently updated in 2025.
Spring is finally here, and with it comes more chances to get outside and help Long Island Sound. Read the Volunteer Newsletter: April 2026 to find volunteer and citizen science opportunities near you.
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Long Island Sound reached a major milestone in water quality this year, with hypoxia, or low oxygen in bottom waters, at its lowest since the Long Island Sound Partnership began tracking the levels in 1987. That means fewer areas of the Sound were uninhabitable for fish, shellfish, and other aquatic animals.
According to results from the Connecticut Department of Energy and Environmental Protection’s 2025 Long Island Sound Water Quality Monitoring Program, hypoxia covered a maximum area of 18.34 square miles (47.5 square kilometers) for the year between July 29 and July 31. Hypoxia, or low-oxygen, conditions persisted for 40 days, from July 14 through August 22, a shorter duration than in many previous years. Over the past decade there were only three other years where the duration of hypoxia was 40 days or less.
Scientists say these results reflect ongoing improvements in water quality, supported by decades of work by federal, state, and local partners to reduce nitrogen pollution through the Long Island Sound Partnership.
“This year’s historic decrease in hypoxia illustrates 40 years of amazing progress through the Long Island Sound Partnership,” said EPA Region 2 Administrator Michael Martucci. “Dedicated efforts and investments by EPA, Connecticut, New York, and local governments have drastically reduced the amount of nitrogen pollution entering the Sound, resulting in smaller affected areas and fewer days of low oxygen.”
Improved oxygen conditions benefit the Sound’s ecosystems and the communities that depend on healthy waters for fishing, recreation, and coastal livelihoods.
Hypoxia happens when excess nutrients, especially nitrogen from wastewater and stormwater runoff, fuel algae growth. When algae or the organisms that eat algae die, they sink to the bottom where bacteria and other microbes feed on them, using up oxygen in the process. This leaves fish and shellfish stressed or displaced and, in severe cases, causes die-offs.
This year also marked the first test of a new Long Island Sound Hypoxia Forecasting Model. Developed with scientists from the US EPA, the model projected that up to 31 square miles of bottom waters could experience hypoxia, peaking around mid-August. The actual results showed a smaller and earlier event, roughly two weeks ahead of the forecast, but within the predicted range.
Tools like the Hypoxia Forecasting Model and the new Hypoxia Toolkit, a collection of educational resources, maps, and animations, help scientists, managers, and residents better understand what’s happening beneath the surface and what actions make a difference.
Residents in the Long Island Sound watershed can help limit excess nutrient runoff with simple actions such as reducing fertilizer use, cleaning up after pets, and keeping storm drains clear.
Learn more about hypoxia in Long Island Sound and explore the Hypoxia Toolkit at https://lispartnership.org/our-vision-and-plan/clean-waters-and-healthy-watersheds/reduce-nutrients/hypoxia-toolkit/.
CONTACT:Stephen Heverly, for National Fish and Wildlife Foundation (NFWF), 301-485-4370, sheverly@thehatchergroup.comJohn Senn, US EPA Region 1 (New England), 857-329-2447, Senn.John@epa.govCarlos Vega, US EPA Region 2, 212-637-3662, vega.carlos@epa.gov
Connecticut (December 2, 2025) – The National Fish and Wildlife Foundation (NFWF) and partners today announced nearly $12 million in grants to organizations and local governments to improve the health of Long Island Sound and its wildlife populations. The grants will leverage more than $8 million in matching contributions from the grantees themselves, resulting in more than $20 million in total conservation impact for projects in Connecticut, Massachusetts, New Hampshire, New York and Vermont.
The 2025 Long Island Sound Futures Fund (Futures Fund) grants will support projects that:
Funding for the grant program comes from the US Environmental Protection Agency (EPA) as part of the Long Island Sound Partnership (LISP), with additional support from NFWF and The Zoetis Foundation.
“Estuaries and their surrounding lands and waters represent some of the most productive wildlife habitats and most economically important areas in the world,” said Jeff Trandahl, executive director and CEO of NFWF. “The Long Island Sound is the second-largest estuary on the East Coast and one of North America’s most biologically diverse estuaries. Its watershed stretches 16,820 square miles across five states, with more than 16,000 miles of rivers feeding fresh water into the sound.
“Sustaining the health of Long Island Sound benefits a wondrous assortment of wildlife while also ensuring prosperity for thousands of communities, large and small.”
The LISP initiated the Futures Fund in 2005 through EPA’s Long Island Sound Office and NFWF. The grant program has a strong history of making environmental improvements by supporting people and communities who value the Sound and take a direct role in its future.
Since its inception, the Futures Fund has invested $68 million in 688 projects. The program has generated an additional $87 million of grantee matching contributions toward these projects for a total conservation impact of $167 million. The projects have reduced 130,000 pounds of nitrogen from entering the Sound, restored 862 acres of fish and wildlife habitat, treated 212 million gallons of stormwater pollution, and engaged 5 million people in protection and restoration of the Sound.
“This year’s Futures Fund projects will support water quality improvements, habitat restoration, and other critical efforts across the watershed that are vital to protecting Long Island Sound,” said EPA New England Regional Administrator Mark Sanborn. “Long Island Sound is a national treasure, and this funding exemplifies EPA’s commitment to supporting the economic and recreational benefits the Sound offers to millions of people.”
“EPA is proud to support conservation and restoration efforts in the Long Island Sound, working alongside our state and local partners,” said EPA Region 2 Administrator Michael Martucci. “These practical projects not only preserve vital ecosystems but also help build a legacy of environmental stewardship for future generations.”
“The Connecticut Department of Energy and Environmental Protection (CT DEEP) stands proudly with the Long Island Sound Partnership and the National Fish and Wildlife Foundation in welcoming another year of impactful Futures Fund projects across the Long Island Sound Watershed,” CT DEEP Commissioner Katie Dykes said. “In Connecticut, eleven distinct NGOs took home a total of 12 awards (Save the Sound was awarded two!) for projects ranging from riparian buffers to fish passage restoration, hands-on science programs to saltmarsh restoration, and a green roof. These are just a few of the ways that today’s grantees are embracing this funding opportunity to further the health of our resources and residents across the Long Island Sound Watershed.”
New York State Department of Environmental Conservation Commissioner Amanda Lefton said “DEC is committed to protecting Long Island Sound, one of New York’s most important natural resources, a vital economic engine, and a place cherished by communities along its shores. The Futures Fund supports projects that strengthen the Sound’s ecosystem by improving water quality, restoring habitats, and encouraging local stewardship, while reflecting a shared commitment with our partners at EPA, NFWF, and CTDEEP. DEC applauds the awardees for the meaningful benefits their work will deliver.”
A complete list of the 2025 grants made through the Long Island Sound Futures Fund is available here. See a list of quotes from elected officials about today’s grant announcement here. To learn more, please visit the NFWF Long Island Sound Futures Fund website or the LIS Partnership Long Island Sound Futures Fund website.
BACKGROUND
Long Island Sound is an estuary that provides economic and recreational benefits to millions of people while also providing habitat for more than 1,200 invertebrates, 170 species of fish and dozens of species of migratory birds. The grant projects contribute to a healthier Long Island Sound for everyone, from nearby area residents to those at the furthest reaches of the Sound. All 9 million people who live, work, and play in the watershed impacting the Sound can benefit from and help build on the progress that has already been made.
About the National Fish and Wildlife FoundationChartered by Congress in 1984, NFWF has grown to become the nation’s largest conservation foundation. NFWF works with the public and private sectors to sustain, restore and enhance the nation’s fish, wildlife, plants and habitats for current and future generations. Since its founding, NFWF has supported more than 7,000 grantee organizations and funded over 23,300 projects that have generated a total conservation impact of $11.3 billion. Learn more at nfwf.org.
About the U.S. Environmental Protection Agency Grants Every year, EPA awards more than $4 billion in funding for grants and other assistance agreements. From small non-profit organizations to large state governments, EPA works to help many visionary organizations achieve their environmental goals. With countless success stories over the years, EPA grants remain a chief tool to protect human health and the environment. Follow EPA Region 1 (New England) on X and visit our Facebook page. For more information about EPA Region 1, visit the website.
About the Long Island Sound Partnership
The Long Island Sound Partnership, developed under the EPA’s National Estuary Program, is a cooperative effort between the EPA and the states of Connecticut and New York to protect and restore the Sound and its ecosystem.
Bioextraction is a process that uses living organisms like shellfish and seaweed to remove excess nutrients—especially nitrogen—from the water.
As shellfish and kelp grow, they absorb nutrients into their tissues. When these organisms are harvested, the nutrients are removed from the ecosystem, improving water quality and supporting healthier coastal ecosystems.
Learn more.
While long-term population trends in oysters in the Sound have not been definitively established, a number of organizations are actively working to restore and build new oyster reefs. Cornell Cooperative Extension of Nassau County, City Island Oyster Reef, and Save the Sound are among the hands-on partners. The Long Island Sound Partnership, through its grant programs provides key funding support for reef restoration, shellfish-based water-quality projects, and community stewardship in the region.
By Erica Casper
This article originally appeared in the Fall/Winter 2025 issue of Wracklines, a publication of CT Sea Grant. View the entire issue here.
In 2003, the Long Island Sound Partnership launched a stewardship initiative to identify the most ecologically and recreationally significant places on coastal Long Island Sound. Experts and community members worked together to highlight 33 areas across Connecticut and New York that deserved special recognition and investment.
These places protect rare habitats, support threatened species, offer public access to the water and provide opportunities for research and education. Since then, the Long Island Sound Partnership has invested millions of dollars in protecting, restoring, and improving these areas.
I’ve been learning about the stewardship initiative since I started working for the Long Island Sound Partnership and Connecticut Sea Grant earlier this year. Each of the Stewardship Areas tells part of the story of Long Island Sound: how it supports both people and wildlife, how it has been shaped by history, and how it continues to change. Some areas I already knew well, such as Bluff Point, Harkness, and Rocky Neck state parks, longtime favorites of mine for spending time outdoors. I was unfamiliar with many others, however, and learning about them on paper sparked my curiosity to experience them firsthand. With that in mind, I recently visited four new-to-me Stewardship Areas in Connecticut: Norwalk Harbor, Charles Island, Barn Island and the Quinnipiac River. They all offered something different, some bustling, some remote, some surprising in their setting. Together, these areas showed me how diverse the Sound’s landscapes are and why they matter, while highlighting unique ways to explore and appreciate what makes Long Island Sound special.
Norwalk Harbor is a hub of activity, where recreation, industry, and conservation come together. Veterans Memorial Park and nearby Calf Pasture Beach provide easy access to the water and lots of options for spending time outside. Whether you’re launching a kayak, watching the boats, fishing from the pier, or just walking along the shore, the harbor invites people in.
Veterans Memorial Park spans 35 acres, with sports fields, paths and a boat launch. It’s open year-round from dawn to dusk. Calf Pasture Beach, one of the area’s most popular spots, offers sandy beach access, lifeguard-supervised swimming, and views of the Norwalk Islands. There’s also a skate park, concessions, and a small boat ramp for kayaks and canoes.
One of the harbor’s most notable features is its oyster industry. Norwalk has been a major source of oysters for generations. If you’ve eaten oysters in New England, there’s a good chance they came from here. That history is still alive in the working waterfront and the educational programs nearby. Oyster boats can often be seen from the beach, and there’s even a recreational shellfishing area there where people can harvest their own. When I visited, the beach was buzzing with energy. Walkers and joggers were enjoying the paved paths. Sailboats glided past in the water. Two summer camp groups from The Maritime Aquarium at Norwalk were exploring the shore and combing through treasures captured by seine net pulls in the shallows. The excitement was contagious as the kids discovered pipefish, pufferfish, crabs, shrimp, and even a horseshoe crab. It was a great reminder that Norwalk Harbor isn’t just a place for recreation, it’s also a living classroom where people of all ages can learn about the Sound.
Charles Island sits just offshore from Silver Sands State Park in Milford. This 14-acre island is home to one of Connecticut’s largest breeding colonies of herons and egrets and has been designated a Natural Area Preserve and a National Audubon Society Important Bird Area. Its dense woods and rocky shoreline offer vital nesting habitat for great egrets, snowy egrets, and other coastal birds.
Geologically, Charles Island is a tied island. It is connected to the mainland by a natural gravel bar that’s only exposed at low tide. It’s a striking feature that draws visitors out along the sandbar, creating a temporary bridge between land and island. But timing is everything. When I visited, I missed my window. The tide had already come in, and the sandbar was submerged. I hadn’t checked the tide chart ahead of time, so I couldn’t cross.
That said, the shoreline and boardwalk at Silver Sands State Park were still worth the trip. The beach is wide, with shallow water and lifeguards on duty during the summer. It’s an accessible place to walk, relax and watch birds overhead. If you’re planning to visit the island itself, though, planning ahead is important. The tides make all the difference, and visiting during nesting season (typically May through August) is discouraged to protect the birds. With a history that includes a tobacco farm, a failed hotel, and a 20th-century retreat center, Charles Island has seen its share of stories. Today, it’s a reminder that some of the Sound’s most interesting places are those that let nature take the lead.
Barn Island, located in Stonington, is the largest coastal Wildlife Management Area in Connecticut and one of the most ecologically diverse. Spanning over 1,000 acres, it includes salt and brackish marshes, intertidal flats, upland forests, a sandy beach, and even a rare sea-level fen. It’s a place where you can experience the full range of coastal habitats, all in one visit.
But Barn Island isn’t just a beautiful landscape. It’s also a vital research site. For more than 60 years, scientists have been studying its wetlands to better understand how marshes respond to sea-level rise and human activity. After misguided efforts in the 1930s to control mosquitoes by digging ditches to drain the marsh, restoration work began and continues to the present. That history has made Barn Island a rich case study for long-term ecological change.
When I walked the trails, I passed from shaded forest into open marsh, with the landscape shifting dramatically from one moment to the next. Dragonflies buzzed around, bees moved from flower to flower, and birds called in the distance. If I could use one word to describe it, I would say “peaceful.” Outside the trailhead is a parking lot and boat launch, offering access for paddling and fishing.
Barn Island offers something for everyone: scientists, birders, hikers, and anyone looking to spend quiet time in nature. It’s also a reminder that conservation takes time, and that places like this can teach us a lot about both change and resilience.
The Quinnipiac River Marsh Wildlife Management Area and State Park in New Haven anchor the Quinnipiac River Stewardship Area, offering nearly 900 acres of tidal marsh, floodplain forest, and upland habitat within an urban setting.
Designated an Important Bird Area by the National Audubon Society, the marshes attract migratory waterfowl and provide habitat for threatened species such as the northern harrier and least bittern. The four-mile Banton Quinnipiac Trail winds through the floodplain, giving visitors a chance to hike, birdwatch, or simply experience one of the rare stretches of green space along the lower river.
This section of the Quinnipiac may not feel as remote as some other Stewardship Areas, but it highlights why urban access to nature matters. For local residents, the river provides habitat for wildlife and a daily reminder that green corridors and healthy waterways can exist even in the middle of a city.
When I visited, I followed part of the trail that began in New Haven. At times it hugged the river’s bends; at others it meandered upland. The sounds of birds and insects mixed with the constant hum of the nearby Merritt Parkway, nature and city pressed close together, separated in places only by a strip of forest and guardrails. Along the trail, I passed a woman with a fishing pole, hinting at quiet fishing spots tucked farther along the river.
These four visits, along with others I’ve explored, are just the beginning. There are still plenty of Stewardship Areas to discover, and each season brings new sights, wildlife and perspectives. Spending time at them is an easy way to connect with the Sound. Grab a trail map, pick a site, and see for yourself why these places matter.
Read the October 2025 Volunteer Newsletter for information about volunteer events in CT and NY in November and December of 2025. You can view a PDF here.
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