Past Eelgrass Surveys

Eelgrass abundance and distribution can vary from year to year, as natural and human-induced disturbances such as storm damage, wasting disease, coastal pollution, and scarring from boats and anchor chains affect eelgrass survival. Historical data on eelgrass is useful in identifying trends in eelgrass distribution and abundance, areas of potential vulnerability, and potential future eelgrass habitats. Historical presence of eelgrass is also a variable included in habitat suitability studies, which are used to identify potential locations to target conservation and restoration efforts. The datasets provided here were compiled from several different sources. Most of the data were collected within the last 30 years, and some were collected from historical records more than 150 years ago. It should be noted that none of the individual datasets cover the entire Northeast region, and temporal coverage is highly variable. As such, these datasets should not be interpreted as providing a comprehensive map of historical eelgrass distribution and abundance in the Northeast. Users should consult the metadata for each dataset for details on methodologies. To download one of the datasets, select the dataset in the list and then click the download link below the map. To more quickly download large datasets or multiple datasets, use the eelgrass file download page. Note that the eelgrass distribution data is presence-only. Because surveys of eelgrass do not encompass all coastal waters, absence of eelgrass in a particular place on the map does not necessarily mean that eelgrass does not live at that location.

5CTEastern Long Island Sound2002USFWS
5CTEastern Long Island Sound2006USFWS
5CTEastern Long Island Sound2009USFWS
5CTEastern Long Island Sound1905 - 1996CT DEEP
3MAMassachusetts coastline1995, 2001MA DEP
2NHGreat Bay Estuary1981UNH/GRANIT
2NHGreat Bay Estuary1986UNH/GRANIT
2NHGreat Bay Estuary1987UNH/GRANIT
2NHGreat Bay Estuary1988UNH/GRANIT
2NHGreat Bay Estuary1989UNH/GRANIT
2NHGreat Bay Estuary1990UNH/GRANIT
2NHGreat Bay Estuary1991UNH/GRANIT
2NHGreat Bay Estuary1992UNH/GRANIT
2NHGreat Bay Estuary1993UNH/GRANIT
2NHGreat Bay Estuary1994UNH/GRANIT
2NHGreat Bay Estuary1995UNH/GRANIT
2NHGreat Bay Estuary1996UNH/GRANIT
2NHGreat Bay Estuary1997UNH/GRANIT
2NHGreat Bay Estuary1998UNH/GRANIT
2NHGreat Bay Estuary1999UNH/GRANIT
2NHGreat Bay Estuary2000UNH/GRANIT
2NHGreat Bay Estuary2001UNH/GRANIT
2NHGreat Bay Estuary2002UNH/GRANIT
2NHGreat Bay Estuary2003UNH/GRANIT
2NHGreat Bay Estuary2004UNH/GRANIT
2NHGreat Bay Estuary2005UNH/GRANIT
2NHGreat Bay Estuary2006UNH/GRANIT
3MASelected Embayments2006 - 2007MA DEP
2NHGreat Bay Estuary2007UNH/GRANIT
2NHGreat Bay Estuary2008UNH/GRANIT
2NHGreat Bay Estuary2009UNH/GRANIT
2NHGreat Bay Estuary2010UNH/GRANIT
1MECoastline2010ME DMR
2NHGreat Bay Estuary2011UNH/GRANIT
1MECoastline1993 - 1997ME DMR
4RIQuonochontaug Pond2000URI
4RINarragansett Bay1988RI CRMC
4RINarragansett Bay1996NBEP
4RIBlock Island, Narragansett Bay2006URI
4RICoastal Ponds2009URI
4RISouth Coast/LIS 1999 - 2000RI CRMC
4RIBlock Island2000RI CRMC
4RINarragansett Bay1848 - 1994RI CRMC
To use the list and map: Click on a survey to zoom to the survey location on the map and to see download links below the map. A selected survey will remain highlighted until another survey is selected.
The list above contains all known historical eelgrass coverage datasets from Connecticut, Maine, Massachusetts, New Hampshire, New York, and Rhode Island. The most current datasets for each state can be found on the Regional Map of Eelgrass. To suggest additional historical datasets for inclusion on this site, please email .