33. Marine Water Quality

The quality of our marine ecosystems is a key aspect of our ability to sustain natural habitats as we develop our coastlines. The quality of shellfish habitat is a useful way to track the overall quality of our coastal ecosystems, because it provides a long-term, consistent indicator that is easy to measure. Shellfish eat by filtering the waters where they live, so their health is closely linked to ambient water quality. When the shellfish are safe for human consumption, the ecosystem is clean. The share of shellfish habitat deemed safe for harvesting by public officials is therefore a simple indicator of water quality and ecosystem health.

How are we doing?

As Figure 33.1 shows, New Jersey’s coastal water quality has steadily improved over the past 25 years, based on the percent of shellfish areas open for harvesting. Between 1976 and 2001, shellfish areas safe enough for harvesting increased from 75 to 89 percent. The vast majority of these, about 77 percent, fully supported shellfish consumption while the remainder were available under seasonal or specially restricted conditions and therefore, partially supported shellfish consumption. New Jersey was recognized by the National Oceanic and Atmospheric Administration’s National Shellfish Register as the state with the greatest amount of restored waters for shellfish harvesting for the period from 1990 to 1995.(1)

What is behind these figures?

Coastal water pollution comes from both point and non-point sources. Point source pollution is discharged from factories, sewage treatment plants, and other discrete, easily identified sources. It includes both manufacturing chemicals and organic wastes. Non-point source pollution is in the water that runs off of streets and fields and into streams and storm drainage systems. In urban and suburban areas, runoff carries chemicals deposited onto the street by automobiles, soil and dust from construction sites and other unpaved areas, and lawn chemicals. In rural areas, agricultural chemicals form an important part of non-point source pollution.

The positive trend in New Jersey’s coastal water quality is likely due in large measure to New Jersey’s efforts under the federal Clean Water Act to improve wastewater treatment and thereby reduce the impact of point sources of pollution. Little has been done nationally or at the state level to address non-point source pollution, which is much harder to identify and therefore more difficult to regulate.

The Department of Environmental Protection has developed a Coastal Non- Point Source Monitoring Strategy to provide the data necessary to identify pollution sources and relating those sources to restrictions on shellfish harvest. The DEP has also established programs to reduce unauthorized discharges to coastal waters. Their efforts will begin to address the non-point sources of marine pollution, and should reduce emergency closures of shellfish waters due to these discharges.(2)

What else would we like to know?

We would like to develop a much clearer picture of the sources and impacts of non-point source water pollution.

Indicator Target:

Targets with which to assess state progress have not yet been established for this indicator.


(1) NJDEP. Environmental Indicators Technical Report, 2nd Edition. Fish & Shellfish Consumption.http://www.state.nj.us/dep/dsr/eitr2001/Trends%20of%20Shellfish%20Harvest.PDF

(2) ibid.