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What’s the difference between a bay and a sound?

July 15, 2005


Primarily, location, location, location.


Look at any chart or map and what do you see? Bodies of water seem to be

randomly labeled sound, bay, lagoon, strait and bight. What’s the correct definition of these terms and what makes a sound a sound? Even experts get confused.


Barrier island systems are usually associated with sounds. Barrier islands are dynamic, narrow ribbons of sand occurring from Maine to Florida on the East Coast. They are subject to erosion and overwash, and are in a constant state of migration. Behind these barrier beaches are protected areas, like salt marshes, that are sheltered from the force of ocean waves. In North Carolina, these protected bodies of water are usually called “sounds.”

The names of sounds can be quite interesting: Stump Sound, Core Sound, Currituck Sound, Pamlico Sound, Roanoke Sound, Topsail Sound, and Myrtle Grove Sound, to name a few. Sounds can have one or more openings to the ocean, and can be salt or fresh water, depending on their distance from a saltwater inlet. Pamlico Sound, for instance, is quite salty and flows directly into the ocean, whereas Albemarle Sound is mainly fresh water and lies 20-plus miles from the ocean.

Bogue Sound

Shallow Bogue Sound is protected by Bogue Banks, a barrier island that extends from Beaufort Inlet at Fort Macon to

Bogue Inlet at Emerald Isle.

Bays are usually embayments in the coastline that open directly into the ocean. The Chesapeake Bay is a perfect example. Bays receive salt water from the ocean and fresh water from rivers. These waters tend to be brackish in composition, meaning they are somewhere between salty and fresh.


The word “bay” can be confused with estuary and lagoon because both involve fresh water from the land mixing with seawater. Estuaries are basically the drowned lower portions of rivers. Lagoons are broad, shallow estuarine systems.


If all this sounds confusing, you’re not alone. These words are very similar and used interchangeably in various areas. These variations are not based on science, but historical and regional usages through time, says Dr. Stan Riggs, professor of geology at East Carolina University in Greenville. There are no absolute answers to this terminology problem.


Sounds, bays, lagoons, estuaries and the like do have one common denominator: They are nursery areas for many marine animals, from fishes to planktonic invertebrates.

A healthy estuary system gathers and holds an abundance of nutrients and provides habitat for birds, fish and other wildlife. They are natural filters, trapping sediments and nutrients to create cleaner and clearer water.


Healthy estuary systems provide millions of jobs for those involved in fishing, boating and tourism. According to the Environmental Protection Agency, there are 102 estuaries in the United States. These national treasures are visited by 70 percent of the entire population. We must all continue to work together to protect these important coastal habitats.