PREP Reports & Publications


Eelgrass in the Great Bay Estuary declined in both distribution and biomass between 2010 and 2011. In 2011, eelgrass was once again mainly present in the Great Bay itself with limited distribution in Portsmouth Harbor and Little Bay. Eelgrass distribution in Great Bay itself decreased between 2010 and 2011 and experienced an alarming 26% loss of biomass in a single year. In Great Bay itself there has been a loss of 35% of eelgrass distribution since 1996. In 2011, despite recent consecutive excellent growing years in terms of weather, we saw a reverse of the trend of slight increases in 2009 and 2010. Nuisance macroalgae in Great Bay continued to proliferate in 2011 and impact eelgrass by smothering eelgrass shoots and reducing shoot density. For the fourth year in a row in the Piscataqua River, there was virtually no eelgrass. The eelgrass bed in Little Bay that first appeared in 2010 expanded greatly. Portsmouth Harbor also showed increased eelgrass distribution in the outer harbor. Overall, eelgrass distribution in Great Bay Estuary from 2010 to 2011 decreased 0.3%. There has been a 35% overall loss of eelgrass distribution in the Estuary since 1996. The 2011 gains seen in Portsmouth Harbor and Little Bay were largely a result of the plant reproductive response to stress and a good growing season, but could not compensate for overall losses, which created a downward trend. The long-term trend of eelgrass decline in the Great Bay Estuary continued in 2011.


Piscataqua Region Estuaries Partnership

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Piscataqua Region Estuaries Partnership

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