Northeast Coast Estuaries: National Coastal Condition Assessment 2015

Setting

The Northeast Coast includes coastal waters of Maine through Virginia, including several important estuaries such as the Gulf of Maine, Cape Cod Bay, Long Island  Sound and the Chesapeake Bay, among others. Geographic features include including rocky coasts, drowned river valleys, estuaries, salt marshes, and city harbors. The Northeast region accounts for a total of approximately roughly 10,000 square miles and is divided into two biogeographical provinces. The Acadian Province—lying north of Cape Cod, Massachusetts—and the Virginian Province—Cape Cod to the Chesapeake Bay[1]. The Acadian Province features smaller watersheds, rocky coasts, and open, well-flushed estuaries. In contrast, the Virginian Province consisting of larger watersheds drained by riverine systems such as the Hudson, Delaware, and Susquehanna rivers that empty into relatively shallow and poorly flushed estuaries. The estuaries of the Virginian Province are very vulnerable to the pressures of a highly populated and industrialized coastal region.

Coastal activities account for an important share of the Northeast’s economy. Commercial and recreational fishing are key industries, particularly in the Chesapeake Bay and on Georges Bank off the New England coast. Crop and livestock production are major components of the mid-Atlantic coastal economy, but they can also be sources of negative environmental impacts associated with the runoff of nutrients, pesticides, and eroded soil. The coastal estuaries provide indispensable habitat for juvenile fish, shellfish, and wintering waterfowl, and they function as buffers against coastal storms and sea level rise[2]. The Northeast Coast region is the most densely populated coastal region in the United States and the aggregated population of the Northeast Region Shoreline Counties has increased by almost 7% from 2010 to 2020[3],[4].

Biological Condition

The NCCA found that in 2015, biological condition was good in 75% of the estuaries in the Northeast, according to the M-AMBI marine benthic index. This is slightly better than the overall national estuarine biological condition and a statistically significant increase of 10% in area rated good from 2010 to 2015.

Eutrophication Index

The eutrophication Index, which examines the potential for estuarine area to undergo social eutrophication based upon measurements of nutrients, chlorophyll a, dissolved oxygen and water clarity, found that 48% of Northeast estuarine area was in good condition and 52% of area was in fair and poor conditions combined. While this was better than the country as a whole, estuaries in the northeast were about as likely to be susceptible to eutrophication as not. This indicates the need for continued improvements in nutrient management in waters that flow into estuaries.

Sediment Quality Index

About 76% of the Northeast estuarine area had good sediment quality based on measures of chemical contaminants found in sediments and laboratory tests of toxicity. This is on par with the rest of the estuarine area in the continental US in 2015 and represents a 20% increase in area rated good from 2010 to 2015.

Ecological Fish Tissue Contaminants

Ecological fish tissue contamination is degraded in the Northeast with 51% of waters in poor condition and 15% in fair. Only 18% of the area is rated good. This represents statistical increases in area rated poor and fair from 2010 to 2015; however when evaluating this change readers should be aware that there was a corresponding decrease in area that wasn’t assessed (from 43% to 16%) from 2010 to 2015, so improvements in fish sampling success may account for the increase in proportions of fair and poor areas. It is important to note that this assessment of potential for adverse effects applies only to wildlife that eat fish and does not apply to people.

Human Health Indicators

More than 99% of Northeast estuarine waters have low levels of bacteria and microcystin and are safe for recreation.

Because field crews were unable to catch fish that were suitable for human consumption, 40% of the estuarine area in the Northeast was unassessed for mercury contamination in fish fillet plug samples; no estimate of area with mercury contamination either above or below the 300 parts per billion human health consumption benchmark is available for that proportion of the Northeast. Less than 1% of Northeast estuarine waters have fish with concentrations of mercury in fillet plug samples exceeding the human health benchmark of 300 parts per billion while fish from 60% of the area posed little to no risk for human consumption. The NCCA implemented new procedures in 2020 in an attempt to increase the proportion of sampled area for this indicator.

A fish fillet “plug” is a small biopsy sample taken from a live fish. The fish is released after sampling.

PCBs and PFOS in whole fish fillets were only assessed in Great Lakes nearshore waters.

Recreational anglers should consult local fish consumption advisories before eating their catch.

To access more indicator graphics please visit the interactive NCCA dashboard.​

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