Anything pelagic has something to do with the ocean, especially the open area far from the shore. Pelagic birds and fish — like tuna, jellyfish, and the Atlantic puffin — live in the open ocean.
The term pelagic zone refers to a column of sea water from the surface to the ocean floor. Scientists divide the pelagic zone of the ocean into sub-categories based on their distance from the surface of the water. This word comes from a Greek root, pelagos, "high sea."