Simplified Food Web of The Lower River

The lower Wicomico River pours into the Chesapeake Bay, making most of the lower river a mix of salt and fresh water and creating an ecosystem similar to that of the Chesapeake Bay. Although some of the species here can be seen throughout the Wicomico River and its watershed, such as the cord grass, american bald eagles, yellow perch, and great blue herons, many species can be found here that would not be found in other sections of the river such as blue crabs, oysters, and clams.

The black arrows show the energy flow from a species to its predator. The blue arrows points from an animal to the plant species that commonly shelters it.
1. Diamondback Terrapins (Malaclemys terrapin)
Diamondback terrapins are named for the growth rings on the top of their shell that are shaped like diamonds. They are the only turtles in the world who only live in brackish water. They nest on sandy beaches May through July and lay eight to twelve eggs. The gender of the egg is determined by the temperature at which they hatch. Females hatch from a lower temperature. Once adults they have few predators although this short list includes herons, large fish, and humans. The nests are attacked by raccoon, foxes, and other mammals.Their biggest threat is habitat loss. Diamondback terrapins prey on crabs, clams, oysters, and other small aquatic species. 
2. Smooth Cordgrass (Spartina alterniflora)
Smooth cordgrass, commonly just called cordgrass, can grow anywhere from three to seven feet tall. When lacking oxygen, another variation of cordgrass grows that is shorter than a foot. It generally gets flooded twice daily and is strongly responsible for preventing erosion. It provides habitats for many fish, including red drum and yellow perch, due to its underground growth. Its stems above ground provide habitats for animals such as bullfrogs and food for species such as crabs and mussels. 
3. Bald Eagle (Haliaeetus leucocephalus)
Bald eagles have a wingspan of up to almost seven feet. They often build their nests in loblolly pines. They are in competition with osprey because they eat many of the same species. A bald eagle diet consists primarily of fish, including native species of red drum, yellow perch, and american shad. They also eat other aquatic species such as the american eel, birds, such as herons and ducks, and mammals, such as raccoon, rabbits, and even white-tail deer. Once adults they are rarely attacked by any animals besides the great horned owl but their eggs will be eaten by raccoon, squirrels, and other mammals. Eagles, like many of the birds in the Wicomico River Watershed, can be found in any portion of the watershed, not just the middle of the river.
4. Blue Crab (Callinectes sapidus)
Their scientific name is Greek for beautiful swimmer and they are the only crabs native to the Wicomico River watershed. Females prefer areas of higher salinity than the males, especially when they are laying eggs. Cord grass is also found in areas of high salinity, making it the perfect habitat for blue crabs. Predators include red drum fish, herons, sea turtles, and fisherman. Crabs will eat small red drum, clams, oysters, and virtually anything, especially if it is already dead. Blue crabs are scavengers. They will even eat another blue crabs if found already dead.
5. Red Drum (Sciaenops ocellatus)
Like most species in this habitat, red drum prefer shallow waters with muddy bottoms, making cordgrass an important species for their survival.They are named for their dark red backs and generally weigh about six to eight pounds. They eat crustaceans and small fish, including blue crabs and bullfrogs. Eagles and heron are some of the red drum's main predators although blue crabs and bullfrogs will eat juveniles also.
6. Yellow Perch (Perca flavenscens)
Yellow perch can reach a length of up to eighteen inches and are often the first fish sighted after winter. They are found in schools of up to two hundred fish. They prefer slow waters with dense underground vegetation, making cord grass a critical part of their habitat. They are a critical species for predators such as eagles, herons, loons, and many other birds. Smaller species do not eat their eggs because they are protected by a jelly-like coating. Yellow perch consume small eels, mussels, insects, and fish eggs. 
7. Hard Clam (Mercenaria mercenaria)
Hard clams can be found slightly below the sand or mud that makes up the bottom of their salty habitat. Clams are born as free-swimmers but shortly after birth grow a foot that they use to attach to a hard surface. They are filter feeders, meaning they suck in water that they pull nutrients out of and eject the unwanted portion. Although they have many predators, some of the most prominent include diamondback terrapins, blue crabs, and humans. 
8. Eastern Oyster (Crassostrea virginica)
Oysters require brackish water that range from eight to slightly over thirty feet deep. They are often found in large groups all attached to one another. Oysters, like clams, are filter feeders. They rely on consuming plankton through filtering water by pumping it through their gills. Although eaten by diamondback terrapins, blue crabs, and eels, over-harvesting by people as well as disease have the largest impacts on population.
9. Bullfrog (Rana catesbeiana)
Bullfrogs are the largest frogs native to the Wicomico River watershed. Cordgrass is one of their best possible habitats, providing food as well as protection from predators. Females grow to be larger than males and can lay up to 20,000 eggs at once. Most potential predators do not eat these eggs because they taste bad, providing protection. Tadpoles and fully grown frogs have more predators including diamondback terrapins, snapping turtles, red drum, bald eagles, yellow perch, barred owls, great blue herons, large mouth bass, and more. They will eat whatever they can manage to consume, ranging from insects to small mammals and includes eels and red drum. 
10. Great Blue Heron (Ardea herodias)
Great Blue Herons are water birds. They can have a wingspan of almost six feet and grow upwards of four feet tall. Although they prefer to nest in trees such as sweetgum, they can still be found in cattails and pickerelweed. Their lodges are also used by canada geese and muskrats once they have abandoned them. They consume yellow perch, along with a large variety of fish, bullfrogs, water snakes, american eels, blue crabs, and even plants such as cordgrass. Their main predators include foxes, raccoons, and hawks. Their varied diet and high tolerance for salinity allows them to be found anywhere in the Wicomico River watershed, whether salt, fresh, or brackish waters. 
11. American Eel (Anguilla rostrata)
The american eel is nocturnal and feeds only at night. During the day one would be found hiding in the mud, as deep as six feet below. Because they are very sensitive to oxygen levels they are often are the first indicator of potential dead zones. They are eaten by bald eagles, herons, yellow perch, and many other fish and birds. These eels also eat yellow perch and other species of fish when they are young but consume mainly frogs, mollusks, crustaceans, and aquatic plants. Their habitat consist of plants found throughout the watershed, including cattails, common reed, and  arrow arum. They can be found in fresh, brackish, and salt water.