Survey Finds that Eelgrass in LIS is Increasing

Stamford, CT (December 11, 2013) — Between 2009 and 2012, eelgrass, an underwater plant that forms meadows that are ecologically important for fish and shellfish, increased by 4.5 percent in Long Island Sound,  according to a recently released report by the US Fish and Wildlife Service (USFWS).

The USFWS National Wetlands Inventory Program assessed 2012 aerial photography for eelgrass at 17 coves, embayments, harbors, and other locations in Connecticut and New York. In total, healthy beds of eelgrass covered an area of 2,061 acres. This compares to 1,980 acres of eelgrass from a 2009 survey. Eelgrass beds increased in 13 of 16 locations, while three showed a decrease. A site in the Connecticut River that was previously found to have a low density 2.1 acre eelgrass bed was not included in the 2012 survey results because it could not be verified with the imagery.

The surveys, conducted every three or four years, have been funded by EPA, through the Long Island Sound Study. Compared to the first survey in 2002, the area of eelgrass has grown by 29 percent.

“An increase in eelgrass is really good news for resource managers trying to protect fish and other wildlife that live along the coast, and it’s a good sign that water quality is improving,” said Mark Tedesco, the director of the EPA Long Island Sound Office.

Eelgrass, a rooted plant with ribbon-like strand, serves as vital nursery habitat for many desirable fish and shellfish species. It can also help prevent erosion and reduce wave turbulence and the impact of storm surges. Eelgrass was once common along the entire coastline of the Sound and in sheltered bays, harbors, rivers, and creeks. In the 1930s, at least 90 percent of eelgrass beds disappeared due to a “wasting disease” along the Atlantic Ocean in Europe and North America. At the time, eelgrass beds in central and western Long Island Sound declined by two-thirds of their original extent, but eelgrass has since returned to eastern Long Island Sound.

Scientists and resource managers believe that improving water quality, including reducing nutrient pollution, contributes to an environment that will favor eelgrass growth. For example, Mumford Cove in Groton, CT, saw a dramatic increase in eelgrass in the late-20th century after a wastewater treatment plant in the area was removed.  In 2012, eelgrass beds in Mumford Cove totaled 91 acres, an increase of nine acres from 2009.

The USFWS report is available through a link on the Long Island Sound Study eelgrass indicator web page:  The page also provides a link to the National Wetlands Inventory website, as well as instructions on how to use an online mapper on the website to view maps of the extent of eelgrass beds at each of the locations.

The Long Island Sound Study is a cooperative effort between the EPA and the states of Connecticut and New York with a mission to restore and protect the Sound and its ecosystem. To learn more about LISS, visit




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