Some fish and crabs may be able to swim away from areas without enough oxygen. But other animals – such as oysters, clams and worms – are not able to swim away, and can die if there is not enough oxygen around them.

Scientists generally agree that the Bay’s creatures need dissolved oxygen concentrations of 5.0 mg/L or more to live and thrive. However, the amount of oxygen an animal needs varies depending on how large or complex the animal is and where it lives.

Bay grass beds form communities that provide food and shelter for many species. Fish, crabs and other animals visit bay grass beds to seek out food and find shelter from larger predators. Bay grasses are also an important source of food for waterfowl such as ducks and geese.