A flock of birds in the water at the Elkhorn Slough Reserve in California.
Estuaries - areas where fresh and saltwater mix - are made up of many different types of habitats. These habitats can include oyster reefs, coral reefs, rocky shores, submerged aquatic vegetation, marshes, and mangroves. There are also different animals that live in each of these different habitats. Fish, shellfish, and migratory birds are just a few of the animals that can live in an estuary.
For example, there are several habitats that make up the Chesapeake Bay. There are oyster reefs where oysters, mud crabs, and small fish may be found. Also in the Chesapeake Bay, there is submerged aquatic vegetation where seahorses, blue crabs, and other fish live. Finally, there is open water where sea turtles or rays can be found.