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Explore Key Indicators of Estuary Health


The NY-NJ Harbor & Estuary Program (HEP) and the Pratt Institute Spatial Analysis and Visualization Initiative have created interactive graphics to illustrate the key indicators of estuary health. For more information on the following indicators of environmental health, please see the State of the Estuary Report.

Pathogens: Enterococcus, 2007-2016

Enterococcus is a bacterial pathogen found in human and animal waste that scientists use to indicate the presence of untreated sewage in the waterways. The more Enterococcus cells in a water sample, the more we can expect that water to contain pathogens that can be harmful to humans. This chart shows the geometric mean for each year using the data for the April to October recreational season. The geometric mean is similar to an average but it better represents the typical number in a set of values such as these. Click on the labels below to focus on a particular waterbody.

Habitat: Fish

Historical accounts of the estuary describe our waters as teeming with fish. Dramatically altered shorelines and benthic environments, a booming commercial fishing industry and water pollution took their toll and now fish populations are a fraction of what they once were. This animation shows the data from a Hudson River survey of juvenile fish over the past 30 years. The population of most of these species is continuing to decline but abundance of the endangered Atlantic sturgeon is trending up and hogchoker, a small flounder, is rebounding. For more information and graphs of these data, see the State of the Estuary Report.
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Habitat: Benthic Index, Sediment Health

One way to determine the health of the marine ecosystem is to survey the animals that live in the superficial sediments of the Estuary. These animals, mostly benthic worms, small mollusks and crustaceans, can be tolerant or intolerant of the historic and ongoing pollution in our waterways. The presence of specific species and their relative abundance is used as an indicator of marine ecosystem health. These data show sediment health is slowly improving until 2013 when species abundance and biodiversity abruptly decline, possibly due to Hurricane Sandy.
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Toxins: Mercury, 1993-2013

The presence of toxic contaminants in sediments is a major factor in the economic and ecological health of the Port. The Hudson-Raritan Estuary has a legacy of toxic contamination due to years of unregulated pollution. Mercury is the estuary’s most problematic heavy metal, capable of bioaccumulating (building up in biological tissues), and organic mercury biomagnifies (increases in concentration as chemical contaminants move from prey to predator species). Concentrations of Mercury in sediments are highest in Newark Bay and the Arthur Kill and are significantly decreasing only in Raritan Bay. For more information and graphs of these data and other heavy metals, see the State of the Estuary.
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Toxics: PAHs

PAHs (polycyclic aromatic hydrocarbons) are contaminants created as a byproduct of burning wood, waste incineration, and vehicle emissions. They also occur naturally in petroleum and coal. PAHs have most likely entered the estuary via oil spills and stormwater runoff from roads, although there was also historical pollution of coal tar into the Estuary. Because PAHs are toxic to the small animals that live in the estuary’s sediments and bottom feeding fish, they decrease the health and diversity of the base of the marine food web. PAHs are declining significantly throughout the Estuary.
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Public Access: Boathouses and Human Powered Boat Trips

Throughout the NY–NJ Harbor Estuary, there are dozens of organizations providing programs that get people on the water in human-powered boats such as canoes, kayaks, and paddleboards. Some organizations additionally provide environmental education and other supplemental programs. These on-water programs are critical for fostering a connection with and stewardship of the estuary, especially for young people. This animation shows the recent growth in both the number of boathouses and the amount of people using them.
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Habitat: Shoreline Types

The shallow water at land’s edge is an important and biologically productive area for fish and wildlife. Aquatic animals use it to spawn. Nutritional sources are more plentiful near the shore. Terrestrial animals and birds are drawn to shorelines for foraging, fishing, temperature regulation and nesting. Many of our estuary’s charismatic species thrive at the interface of water and land, including turtles, shorebirds and crustaceans. As our waterfronts were developed, much of the shoreline was hardened with bulkheads or riprap in order to stabilize it for nearshore development or shipping infrastructure. Today only about 70% of the estuary’s shoreline are natural marshes, mudflats or beaches.

Explore the map and click on shoreline points to learn about the variety of shoreline environments in the Hudson River Estuary, and projects where engineers and ecologists are working together to improve the waterfront.