An Indian village depicted in an early Dutch map of “New Netherland.”


Perhaps as many as 10,000-15,000 Indians live near Long Island Sound, harvesting bountiful fish and game along the shore and in interior forests.

Source: Tom Andersen, This Fine Piece of Water: An Environmental History of Long Island Sound (Yale University Press, 2002)


In 1614, Dutch explorer Adriaen Block completes his final expedition to the Sound. Block, the first European to sail the entire Sound, opens the Sound to trade. Colonial settlers clear forests for farms and settle in seaside communities for trade, fishing, and whaling. Indian tribal influence dwindles by the late 1600s.

Source: Tom Andersen, This Fine Piece of Water: An Environmental History of Long Island Sound (Yale University Press, 2002)

Stamford Manufacturing Company, Cove Island, Stamford.
Stamford Manufacturing Company, Cove Island, Stamford.


Commerce grows, and the Sound and its tributaries become known for brass and metal finishing, textiles, hatmaking, and oystering. The Sound is prized for its beauty and becomes a source of inspiration for American Impressionist painters. But the Industrial Revolution also brings intense growth and pollution.

Source: Tom Andersen, This Fine Piece of Water: An Environmental History of Long Island Sound (Yale University Press, 2002)


Manufacturing declines, while postwar housing production leads to a population boom and suburban sprawl. The first comprehensive study of water quality shows evidence of human impact affecting oxygen levels.


Low levels of dissolved oxygen contribute to fish kills in the western Sound. Nationally, concerns about the health of America’s waterways lead to the 1972 federal Clean Water Act.

Menhaden kill, along the Mianus River, 1988.
Menhaden kill, along the Mianus River, 1988.


Congress creates the Long Island Sound Study (LISS). Field surveys identify low levels of oxygen, later related to nitrogen pollution, as the greatest environmental threat to the Sound.


LISS adopts the Comprehensive Conservation and Management Plan (CCMP) to restore and protect the Sound. The cleanup plan includes actions to address hypoxia, reduce toxic substances and pathogens, and restore natural habitats.

Grassland restoration, Caumsett State Park, Lloyd Harbor, NY


CT, NY, and the EPA adopt a plan to reduce human sources of nitrogen pollution to the Sound by 58.5 percent by 2014. Through the Habitat Restoration Initiative, the Study also adopts goals to restore 2,000 acres of habitat and 100 miles of river for fish passage.


EPA approves CT and NY’s “Total Maximum Daily Load” of nitrogen to the Sound, allocating responsibility to meet the 58.5 percent reduction goal to reduce nitrogen through wastewater treatment plant upgrades. Originally targeted for completion by 2014, it was extended to 2017 in order to provide time for New York to complete upgrading large wastewater treatment plants.


LISS adopts the 2003 Long Island Sound Agreement, establishing measurable targets to implement the CCMP and to restore the health of the Sound by 2014, the 400th anniversary of Block’s final exploration.


LISS Habitat Restoration Initiative reaches its goal of adding 100 river miles of fish passage, one year ahead of schedule. Since then new goals have been established and met. As of 2018, LISS has added 417 river miles with a goal of reach 507 miles by 2035.

Branford Water Supply Dam Fishway (completed 2005) added 5.6 miles of fish passage


LISS establishes the Sentinel Monitoring Work Group to examine the effect of climate change in different areas of the Sound and its coast. Researchers and resource managers will collect information to help the region understand potential climate change impacts and to learn how to adapt to climate change by adjusting the way Long Island Sound is managed.


The LISS Management Conference agrees to a new Comprehensive and Conservation and Management Plan with ambitious ecosystem targets to achieve for the next 20 years.


Connecticut and New York meet its 58.5 Total Maximum Daily Load of nitrogen reductions, one year ahead of schedule. As of 2018, over 50 million fewer pounds of nitrogen a year are discharged into Long Island Sound from the early 1990s.

Upgrades to the Hunts Point wastewater treatment plant in the Bronx have prevented over 7 million pounds of nitrogen a year from being discharged into the East River.


The LISS Habitat Restoration Initiative meets its goal to restore 2000 acres, two years ahead of a revised target. A new goal, to restore a total of 2,650 acres (or 1,000 acres if starting from a 2014 baseline of 0) by 2035.

NYSDEC staff with volunteers and Save the Sound plant tidal wetland grasses at Sunken Meadow State Park in 2016.


The Long Island Sound Futures Fund, managed by National Fish and Wildlife, celebrates 15 years of conservation success. Grant funding reached record numbers when $2.7 million was awarded for thirty-five projects in 2019.

Common terns preen about Long Island Sound.


The Long Island Sound Community Impact Fund (LISCIF) is announced, a new grant program formed by a partnership with Restore America’s Estuaries, the U.S. Environmental Protection Agency, and the Long Island Sound Study. LISCIF aims to build capacity for organizations in communities facing disproportionate environmental and human health risks, provide technical assistance to organizations in historically underserved areas, and support proposals that improve access to the Long Island Sound while reducing overall environmental health risks.


The Long Island Sound Study, in collaboration with Connecticut Sea Grant and New York Sea Grant, launch the Long Island Sound Resilience Resource Hub website. The site offers comprehensive tools, guidance, and information to support sustainability and resilience efforts in the region and empower coastal communities against environmental challenges.

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