A method for operation of a closed cage for marine organisms in the sea is described, where the cage is defined by a watertight cloth (14) that is fastened in a floating anchoring ring (20) on the sea surface, as the cage is supplied with new water by pumping it in from the sea and water is let back into the sea outside the cage in an overflow, and it is characterised in that the new water is pumped up from the sea by the operation of a pump house (246) that is arranged in a pipe-formed body (40) connected to the bottom of the cage, and the water is led out into the cage (10) some distance above the bottom of the cage, and water is let out via an overflow out through a number of ducts (80, 82) that are formed in the anchoring ring (20) from the inside (12a) of the cage into the sea (12b) on the outside of the anchoring ring (20). Furthermore, the invention relates to a new construction to supply new water to the cage from the sea depths below the cage as given in the introduction, and also a device for an anchoring ring (20) for anchoring of a closed cage (14) for marine organisms in the sea.
