An autonomous open-ocean fish-farming structure has a submersible cage enclosure tethered to a topside buoy. The topside buoy stores feed, is equipped with radio telemetry to communicate positioning signals transmitted from external sources, and generates electrical power using, for example, a hybrid solar OTEC heat engine. The structure is navigated and maintained in a geostationary position within the ocean environment by means of position-correction technology and is propelled by thrusters attached to the cage enclosure and, optionally, to the underside of the topside buoy. The self-positioning, self-powered fish-farming structure enables unmanned, extended marine deployment in deeper ocean waters without the need for tethering or anchoring to the ocean floor. Multiple structures can be maintained in a spaced apart configuration to comprise a flotilla of fish farming structures attended by a tender ship that is autonomous, easily serviced and conveniently relocated.
