An exemplary embodiment of an aquaculture cage of the invention has a buoyant structure configured to float on a water surface, an aquaculture net portion made of a material that is corrodible by salt water and attached to the buoyant structure for positioning a top of the aquaculture net portion at a distance below the water surface, where the aquaculture net portion encloses an interior of the cage from the top of the aquaculture net portion to a bottom of the aquaculture net portion to retain marine life, and an upper enclosure portion enclosing space above the aquaculture net portion for preventing the marine life from escaping over the top of the aquaculture net portion, where the upper enclosure portion comprises a material that is substantially non-corrodible by salt water.
