Executive Summary Headlines:
o Great Bay lost 21% of its eelgrass from 2012 to 2013.
o As of 2013, the Great Bay Estuary has lost 50% of its eelgrass since 1996.
Once again, eelgrass in the Great Bay Estuary declined in both distribution and biomass between 2012 and 2013, continuing the long-term trend of eelgrass loss. In 2013, Great Bay itself lost over 20% of its eelgrass (333 acres) and biomass decreased, amounting to about 400 tons, down from 1600 tons in 1996. These eelgrass losses are alarming and not sustainable. In Great Bay, eelgrass distribution has declined 49% since 1996. Nuisance macroalgae in Great Bay continued to proliferate in 2013 and to impact eelgrass at the shallow edges of the beds, of concern since eelgrass is also disappearing at the deep edges from poor water clarity. The eelgrass bed in Little Bay that first appeared in 2010 has now disappeared, with no eelgrass present in Little Bay in 2013. In the Piscataqua River, the small eelgrass bed that originated in 2011 continued to expand, increasing by 5 acres. In 2013, there was a slight decrease (4%) in eelgrass distribution in Portsmouth and Little Harbors. Overall, eelgrass distribution in the Estuary from 2012 to 2013 decreased 20%. The longterm trend of eelgrass decline in the Great Bay Estuary continued in 2013, with a 50% loss of eelgrass distribution estuary-wide since 1996.
Piscataqua Region Estuaries Partnership
Short, Frederick T., "Eelgrass Distribution in the Great Bay Estuary for 2013" (2014). PREP Reports & Publications. 348.