The Great Bay Estuary – A Natural Treasure in Need of Protection

Nestled between New Hampshire and Maine, the Great Bay estuary is one of New England’s most remarkable natural resources. It lies at the confluence of tidally driven seawater from the Gulf of Maine and freshwater from seven major river systems – the Salmon Falls, Cocheco, Bellamy, Oyster, Lamprey, Squamscott, and Winnicut. Great Bay’s connection to the Gulf of Maine substantially influences the dynamics of the estuary, resulting in some of the strongest tidal currents in North America, as seawater must travel 12 miles inland through the Piscataqua River and Little Bay before reaching Great Bay.

This geographic configuration makes Great Bay one of the nation’s most recessed estuaries and it is often referred to as New Hampshire’s “hidden coast.” The watershed extends more than 1,000 square miles reaching many miles north of Portsmouth, New Hampshire’s only port. With over twenty percent of the watershed in the state of Maine, the estuary has defined the cultural history of the region since the first permanent settlements were established in 1620’s. 

For centuries, Great Bay has supported human activities as people were drawn to its abundant resources. Today, the estuary provides critically important habitat for a wide variety of fish, birds and other wildlife and remarkable recreational opportunities that contribute enormously to the coastal heritage of New Hampshire’s Seacoast region and southernmost Maine.

In light of these extraordinary values, Great Bay has been designated an estuary of national significance by both the Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA). EPA’s Piscataqua Region Estuaries Partnership (PREP) and NOAA’s Great Bay National Estuarine Research Reserve (GBNERR) have developed comprehensive management plans that have resulted in research, education and land conservation initiatives designed to address the critical issues facing the estuary. Great Bay is also home to the Great Bay National Wildlife Refuge.

The estuary provides important fish habitat and is designated Essential Fish Habitat (EFH) by the National Marine Fisheries Service for numerous fish species in various life stages including Atlantic cod, haddock, pollock, yellowtail flounder, Atlantic mackerel and bluefish. Other species, such as a variety of herring, are forage fish that support the Gulf’s commercial fisheries by serving as an important building block in the marine food chain. Still other species, such as striped bass and bluefish, are important recreational fisheries.

Regrettably, the health of the estuary is in jeopardy. Similar to the multiple stressors affecting the Gulf of Maine – primarily related to population growth and low‐density sprawl – there is concern among scientists that Great Bay is approaching a tipping point which, once crossed, will make its recovery incredibly challenging and costly.

As the Great Bay-Piscataqua Waterkeeper my role is serving as the “eyes and ears” of the estuary, advancing needed policies and innovative solutions, and building a public voice to protect Great Bay for future generations. There is much work to be done.

The most recent State of the Estuaries report (PREP, 2013) documents a troubling trend – that with only three of fourteen pressure and condition indicators moving in a positive direction, the health of the estuary is in jeopardy due to increases in nutrients pollution. Most notably, impervious surfaces are increasing at six times the rate of population growth, making it that much more difficult to reduce nitrogen pollution.

 Eelgrass, the cornerstone of the estuary’s ecosystem, has suffered resulting in severe declines in the Piscataqua River and Little Bay. The overall distribution of eelgrass has decreased by more than a third since 1996 and biomass loss has been even more dramatic, declining by over two-thirds during the same timeframe. These habitat changes have negatively impacted local fish species. You can read about some of these changes as observed by a local scuba diver here. Due to disease, there also has been a dramatic decrease in oyster populations with a ninety percent decline since 1993.  Recent restoration efforts are aimed at slowly building back populations.

Despite the changes, one constant remains – Great Bay is a national treasure. I encourage you to visit the region and discover Great Bay’s wonders.

For more information about the Great Bay-Piscataqua Waterkeeper and my work to protect the Great Bay estuary, visit: You can also follow me on Facebook and Twitter.