The deeper part of the sea or ocean in which no light penetrates / (sport fishing) open sea (part of the sea out of sight of land)

Of, related to or located in the deeper part of the sea. / (sport fishing) Of or related to open sea. / (of a port) Able to accommodate the largest ships.

plural of deep sea

a species of shrimp found in cold parts of the Atlantic and Pacific Oceans, Pandalus borealis.

plural of deep-sea prawn