Chesapeake Bay

The Chesapeake Bay is the largest estuary in the United States. It runs north-south from the mouth of the Susquehanna River to the Atlantic Ocean. It is one of the most productive estuaries in the world, with over 3,600 species of animals and plants. It provides vitally important habitat for wildlife, lots of recreational opportunities for people and it is an important fishery upon which both people and wildlife depend.

Crabbing in Chesapeake Bay

People and the Chesapeake Bay

The Chesapeake Bay watershed includes parts of six states and is home to some 17 million people, including the cities of Washington, DC, and Baltimore, MD. The watershed's many rivers provide not only drinking water but also places for fishing, boating and birding opportunities. Its wetlands are sites for bird watching, boating and waterfowl hunting.

The Bay itself is popular for boating and recreational fishing. The Chesapeake's commercial fishery is worth billions of dollars and includes blue crab, rockfish, menhaden and eastern oyster. The Bay also includes two of the biggest East Coast commercial ports--Baltimore and Hampton Roads.


Wildlife in the Chesapeake Bay

American Black duck

The Chesapeake Bay is a very large and complex ecosystem with many kinds of wildlife habitats, including forests, wetlands, rivers, and the Bay estuary itself. The Bay supports 3,600 species of plant and animal life, including more than 300 fish species and 2,700 plant types.

The waters of the Bay are a mix of saltwater and freshwater. Saltwater comes into the Bay from the Atlantic Ocean and freshwater enters the Bay through rivers and streams as well as through underground water flows called groundwater. Many of the Bay's wildlife, including the blue crab and waterfowl depend on underwater bay grasses that grow in the shallow waters.

  • FISH - There are over 350 varieties of fish in the Bay, including some that prefer freshwater such as the pumpkinseed; some that are migratory, such as the summer flounder; and some that move between fresh and salt water, such as the American shad.

  • INVERTEBRATES - Hundreds of invertebrates, like the blue crab and the oyster, and other less edible but important species such as the horseshoe crab, call the Bay home. Oysters, once very populous in the Bay, have greatly declined. Oysters filter and clean water, and their loss, has affected the water quality of the Bay and the health of other species.

  • BIRDS - At different times of the year you can find birds from raptors such as the bald eagle and osprey, to waterfowl like swans and ducks, and migratory birds like the sanderling and ruby-throated hummingbird. The region's beaches support some of the largest populations of shorebirds in the western hemisphere, such as the red knot and piping plover. For waterfowl, the Chesapeake is a major stopover site and wintering ground along the Atlantic Flyway. Every year one million waterfowl winter in the Bay region.

  • REPTILES - Four kinds of sea turtles come to lower reaches of the Bay, the loggerhead, Atlantic Ridley, leatherback and green sea turtle.

Threats to the Chesapeake Bay

Land Use and Pollution

Over 17 million people live in the Chesapeake Bay watershed and have made their imprint upon its lands and waters. About 58 percent of the watershed is forest, while the rest has been converted by people to agricultural (22 percent), suburban and urban uses (9 percent). These land use changes have impacts on the Bay.

One of the Bay's biggest problems is too many nutrients in the water. Excess nutrients come from many sources, including treated wastewater, runoff from agricultural areas, runoff from suburban areas such as lawn and garden fertilizers and septic systems, and even air pollution.

  • Too many nutrients: Although it may not sound like a bad thing, too many nutrients can cause a lot of problems in the Bay. Phosphorus and nitrogen are limiting factors for plants. With the addition of run-off nutrients, algae plants have nothing to keep them in check--they grow into giant blooms. Algae blooms blocks sunlight that underwater bay grasses need to survive. Many Bay species depend on grasses for food and protection. Algae blooms also take oxygen from the water that species like crabs and oysters need to survive.

  • Loss of forests and wetlands: Forests and wetlands can serve as a sink for excess nutrients--absorbing them before they reach the Bay. But in urban and suburban areas around the Chesapeake Bay many of the forests and wetlands have been removed. 100 acres of forest habitat in the Bay watershed are lost each day due primarily to development.

  • Too many hard surfaces: The watershed is covered with too much pavement and other hard surfaces that water cannot run through, such as roads, rooftops, sidewalks, and parking lots (also called "impervious surfaces"). These hard surfaces make up 21 percent of all urban lands in the Bay watershed. Not only do they contribute to the excess nutrients (by making it easier for nutrients to be picked up by rain), they also have their own set of problems. Water that falls on these surfaces cannot be slowly absorbed into the ground to replenish area groundwater, but instead flows quickly into streams and rivers, causing erosion, or directly into storm sewers, causing flooding.


Global Warming

Global warming threatens to not only exacerbate many of the environmental threats already facing the Chesapeake Bay, it is also causing a rise in sea level that is eating away the diverse estuaries and wildlife habitat. Learn more about sea-level rise and the Chesapeake Bay >>  


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