Vast expanses of intertidal sand/mudflats serve as a critical link in the food web of nearshore biological communities in many coastal areas of Alaska. The rich abundance of benthic invertebrates residing within the sediments of intertidal flats and the large network of subtidal channels that bisect these flats provide a significant prey resource for numerous species of fish, crabs, birds, and marine mammals.
One of the largest expanses of intertidal mud/sand flats occurs in the Copper River Delta and southeastern Prince William Sound (Orca Inlet). The estuarine nature of this system results in mixing of nutritional sources from riverine, estuarine and marine ecosystems, which fuel secondary productivity.