The ocean's pelagic zone is an ecological realm that includes the entire ocean water column. It is also sometimes defined as the part of the open sea or ocean that is not near the coast or sea floor.
The pelagic zone of the ocean occupies approximately 1,370 million cubic kilometers (330 million cubic miles) with a mean depth of 3.68 kilometers (2.29 mi) and maximum depth of 11 kilometers (6.8 mi). Fish that live in the pelagic zone are called pelagic fish. Pelagic life is found throughout the water column, although the numbers of individuals and species decrease with increasing depth. The regional and vertical distributions of pelagic life are governed by the abundance of nutrients and dissolved oxygen; the presence or absence of sunlight, water temperature, salinity, and pressure; and the presence of continental or submarine topographic barriers.