The Delaware Bay Looks Reddish - Don't Panic

If this week you see portions of the Delaware Bay, Stow Creek and Mad Horse Creek looking reddish in color, don't panic. It is not pollution, red tide or anything dangerous to wildlife, fish or people.

Two dye applications will be made in the upper bay in Salem County starting near early morning high tides the week of April 9 and continuing until late evening.

This dye release is a way to measure water flow and dispersion in waters used for shellfish harvesting. The dye used in the study is not harmful to people or the environment and is used commonly in water-quality and dispersion tests.

Information collected during this study will be used to evaluate potential water quality improvements that would result in a water classification upgrade.

The dye will be pumped into the bay from a point on land near Stow Creek. The extent of discoloration could be fairly widespread but will disperse.

The study is known as a hydrographic dye dilution study and is conducted in conjunction with the U.S. Food and Drug Administration to aid in the classification of shellfish harvesting waters. Stormwater runoff from uplands and wetlands inhabited by wildlife affects the quality of water in the bay.

The DEP’s Bureau of Shellfisheries and Bureau of Marine Water Monitoring manage and protect more than 720,000 acres of estuarine and ocean beds used to raise clams, oysters and mussels for public consumption. The DEP works closely with the FDA and New Jersey Department of Health to ensure the safety of shellfish brought to market.


For more information on the DEP’s Bureau of Shellfisheries: nj.gov/dep/fgw/shelhome.htm

For more information on the DEP’s Bureau of Marine Water Monitoring: nj.gov/dep/bmw/

Source: nj.gov/dep/newsrel/2018/18_0025.htm