Topic
Seagrass & Tidal Marsh
Seagrass & Tidal Marsh data provide information about the location and extent of coastal wetlands and seagrass meadows, and quantification of marsh and seagrass soil properties and biogeochemistry.
Latest Updates
07-Apr-2026 New and Updated Regional Seagrass Data
30-Mar-2024 New High-resolution Maps of Northeast U.S. Salt Marsh Carbon and Soil Properties
Data Providers and Sources
- Natural Resources Conservation Service (NRCS)
- U.S. Environmental Protection Agency (EPA) – Region 1 (EPA R1)
- National Aquatic Resource Surveys (National Wetland Condition Assessment)
- U.S. Fish and Wildlife Service (USFWS) – National Wetlands Inventory (NWI)
- U.S. Geological Survey (USGS)
- National Oceanic and Atmospheric Administration (NOAA) – Office for Coastal Management
- North Atlantic Landscape Conservation Cooperative (NALCC)
- Conservation Management Institute at Virginia Tech (contracted by NALCC)
- University of Massachusetts Amherst
- Saltmarsh Habitat and Avian Research Program (SHARP)
- University of New Hampshire (UNH) – Geospatial Science Center
- University of Rhode Island (URI) – Environmental Data Center (EDC)
- Bates College
- Virginia Tech – Conservation Management Institute
- Maine Department of Marine Resources, Bureau of Resource Management
- Maine Department of Environmental Protection (DEP)
- New Hampshire Department of Environmental Services (DES)
- Massachusetts Department of Environmental Protection (MassDEP)
- Massachusetts Division of Marine Fisheries (DMF)
- Rhode Island Coastal Resources Management Council (CRMC)
- Connecticut Department of Energy and Environmental Protection (CT DEEP)
- New York Department of Environmental Conservation (NYSDEC) – Seagrass Management Program, Natural Heritage Program, Peconic Estuary Partnership
- Piscataqua Region Estuary Partnership
- Long Island Sound Partnership / Long Island Sound Study
- Long Island South Shore Estuary Reserve Program
- Narragansett Bay National Estuarine Research Reserve (NBNERR)
- Rhode Island Eelgrass Task Force
Data Considerations
The Portal displays regional datasets related to seagrass and tidal marsh. However, data within these habitats are also routinely collected at fine spatial and temporal scales. Each state/program uses a different habitat survey frequency (see layer “Seagrass Survey Areas” for more information, for example) and suite of methods. These details are important for users seeking information about the precise location/extent/condition of particular seagrass meadows or particular marshes. Users should contact the relevant entity in that geographic area to obtain more detailed or more recent data, important context about how the data were collected, and other contextual information known by these experts.
To assist Portal users in finding the relevant experts that may know more about coastal vegetation habitats and trends in the northeast, the NROC Coastal Vegetation Workgroup has assembled the following list of groups throughout New England that actively map, assess, and study seagrass and tidal marsh habitats.
Seagrass Resources
The East Coast SAV Collaborative’s mission is to bring together experts in SAV research and management from each of the U.S. East Coast states from NC to ME to share ideas and information, provide training and resources, and collaborate on efforts that bring actionable science to the forefront of our SAV management strategies. Contact: eastcoastsavcollaborative@gmail.com
Northeast Regional Eelgrass Restoration Collaborative
A collaborative of scientists and managers from government, NGOS, community, and academic organizations with the aim to design an experimental and climate ready regional restoration and management strategy for eelgrass. Contact: Phil Colarusso
Maine
Massachusetts
Rhode Island
- RI Eelgrass Mapping Taskforce: A consortium of estuarine scientists that work collectively to map and monitor eelgrass coastal Rhode Island waters; a collaborative led by:
-
Narragansett Bay Estuary Program SAV Working Group
- Facilitate cross-state collaboration and coordination specifically for Tier 1 aerial photography mapping and workshops. Advise management agencies of the latest research, providing outreach on specific topics and advocacy when necessary.
- Contact: Courtney Schmidt
- RIGIS Eelgrass Locations (polygons)
Connecticut
- CT Eelgrass Working Group: Convened by the Connecticut General Assembly, Environment Committee in response to Connecticut General Assembly Special Act No. 23-7, introduced in House Bill No. 6480, approved June 26, 2023. The charge to the group was to “develop strategies for the preservation, restoration and expansion of eel grass along the state’s shoreline.”
- CT DEEP eelgrass data
Long Island Sound
- Long Island Sound Eelgrass Collaborative: Formed in 2023 to implement elements of the 2022 Eelgrass Management and Restoration Strategy (Long Island Sound Study, 2022)
- LIS Partnership Eelgrass Strategy
- Eelgrass extent data
New York
- New York’s Seagrass Protection Act (N.Y. Envtl. Conserv. Law §§ 13-0701 to 13-0705)
- NYDEC Seagrass Management
- The most updated data on seagrass distribution within several of New York’s estuary programs (including the Long Island Sound Study, Peconic Estuary Program, and the South Shore Estuary Reserve) has been summarized in one map available here: New York seagrass habitat.
Tidal Marsh Resources
A network of over 140 state, federal, tribal, nonprofit, and university scientists and coastal land managers that span Massachusetts, with partners from New Hampshire, Maine, and Rhode Island. Co-led by the Massachusetts Office of Coastal Zone Management and the University of Massachusetts, Amherst, Gloucester Marine Station, the SMWG is one of five Mass ECAN (Ecosystem Climate Adaptation Network) Work Groups.
Maine
New Hampshire
- New Hampshire Salt Marsh Plan: Great Bay NERR and NH Dept of Fish & Game with implementation by the New Hampshire Salt Marsh Task Force
- NH Salt Marsh Plan data viewer
- NH salt marsh habitat data (2013)
- NH salt marsh habitat data (2023) [In progress]
Massachusetts
- MassDEP Wetlands Program
- Interagency Coastal Wetlands Climate Resilience Workgroup (MassDEP Wetlands Program, MassCZM, Mass Fish & Game, MEPA Office, MA Executive Office of Energy and Environmental Affairs)
- MassGIS NWI
- MA Sea Level Affecting Marshes Model (SLAMM)
- Geospatial Characterization of Salt Marshes for Massachusetts
- Waquoit Bay National Estuarine Research Reserve
Rhode Island
Connecticut
Long Island Sound
- Long Island Sound Partnership – Salt Marsh Monitoring and Analysis Network
- LIS SLAMM
- USGS Coastal wetlands data for Long Island Sound
New York
- NYDEC Tidal Wetlands
- Regulatory tidal wetlands data
- NYDEC Environmental Resource Mapper references NWI data for marshes
Status
Seagrass Meadows, Seagrass Survey Areas, and Historical Seagrass Extent data were updated in March 2026, but the majority of data in the regional layers reflect seagrass meadows as surveyed between 2019-2024.
Tidal Marsh Vegetation Classification data are derived from imagery collected between 2014-2015.
Blue carbon layers generally reflect carbon stocks in habitats mapped between 2010-2020.
NROC’s Coastal Vegetation Workgroup identifies new or updated data that will improve existing data products and data/information gaps that hinder understanding of important habitats and limit decision making. They advance data development or data collection for those defined gaps, discuss research, assessments, and models that are being advanced by any of the member participants, and integrate relevant research and information into the Northeast Ocean Data Portal.
Examples of Data
- Seagrass Meadows
- Tidal Marsh Vegetation Classification
- Blue Carbon Stocks (MgC) – Eelgrass Meadows
- Blue Carbon Stocks (MgC) – Tidal Marsh
- Northeast Salt Marsh Soil Organic Matter (percent)