Clean Waters and
Healthy Watersheds

Improve water quality by reducing contaminant and nutrient loads
from the land and the waters impacting Long Island Sound.

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A woman kayaks in the Black Hall River near the mouth of the Connecticut River in Old Lyme, Connecticut. Credit: Jerry Monkman/Ecophotography

Thriving Habitats
and Abundant Wildlife

Restore and protect the Sound’s ecological balance in a healthy, productive, and resilient state to benefit both people and the natural environment.

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Harp seal resting on beach in Madison, CT, waving flipper to warm itself in winter.

Sustainable and
Resilient Communities

Support vibrant, informed, and engaged communities
that use, appreciate, and help protect Long Island Sound.

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The mouth of the Saugatuck River in Westport, CT.

Sound Science and
Inclusive Management

Manage Long Island Sound using sound science and cross-jurisdictional
governance that is inclusive, adaptive, innovative, and accountable.

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UConn Professor Beth Lawrence collects data on surface water salinity with student Madeline Kollegger at a Barn Island tidal marsh. Photo by Emily Couture (CAHNR)/UConn.

The Long Island Sound Study (LISS) is a cooperative effort involving researchers, regulators, user groups and other concerned organizations and individuals. These people are working together to protect and improve the health of the Sound.

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Logo of Shell Day Connecticut August 24, 2023
At the Beardsley Park Zoo in Bridgeport, CT stormwater travels through the curb cut into the vegetation of this rain garden for treatment instead of directly entering the storm drain.
Sound Spotlight

Horseshoe Crab event honors Dr. Jennifer Mattei, founder of Project Limulus

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Long Island Sound
By The Numbers

Square Miles

Area of the Long Island Sound


Average Depth

18 trillion

Water Volume


Length of Coastline


Population Living Within 50 miles

Dollars (2015)

Estimated Value to the Local Economy Per Year


No. of Finfish Species Found in the Sound

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Sound Fact
Monitoring Eastchester Bay for the Unified Water Study

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