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.

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 contact@northeastoceandata.org.