ABSTRACT
This chapter considers marine mammals, it is worth noting that several nonmarine species or populations of seals exist, including the freshwater Baikal seals, Caspian seals, and Ungava harbor seal subspecies. It describes marine mammals as a function of their feeding ecology, thereby providing a framework for characterizing risks that are related to dietary exposure. Marine mammals live partly or entirely in the aquatic environment, which is at the receiving end of deliberate or accidental discharges of thousands of industrial, agricultural, and urban pollutants. Healthy marine mammal populations reflect a healthy aquatic environment, thus marine mammals can serve as integrative indicators of aquatic food web quality. By establishing regulations, guidelines, best practices, and principles that protect marine mammals from different types of contaminants, one may achieve a broader objective, namely the protection of marine ecosystem health. Metabolism by vertebrates removes the opportunity for food web biomagnification, and hence, reduces the risk of dietary exposure and subsequent accumulation in marine mammals.
