How much dissolved oxygen do animals need?
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.
Worms and clams that live in the Bay's muddy bottom – where oxygen levels are naturally low – only need dissolved oxygen concentrations of at least 1 mg/L.
Fish, crabs and oysters that live or feed along the bottom require dissolved oxygen concentrations of 3 mg/L or more.
Spawning migratory fish and their eggs and larvae need up to 6 mg/L during these sensitive life stages.Areas with less than 0.2 mg/L of dissolved oxygen are called anoxic. Most animals cannot live in these areas, which is why they are often called “dead zones.”