Breeding of aquatic animals in a controlled environment

Claim 1

In a process for breeding aquatic animals in a controlled environment wherein the aquatic animals are maintained in a water reservoir open to the atmosphere and which has fresh water introduced and fecal waste containing water discharged, and wherein the oxygen content of the water present in the water reservoir is kept at a value corresponding to desirable growing conditions for the aquatic animals by the introduction of a gas consisting essentially of oxygen or oxygen-enriched air, the improvement which comprises introducing the gas directly into at least one bell partially immersed in the water, the point of introduction of the gas within the bell being under and/or above the water level therein, feeding water to the lid zone of said bell, said last mentioned water being derived at least in part from water withdrawn from the water reservoir, distributing the water into a plurality of partial streams of water, passing the stream of water from the lid zone of said bell downwardly inside said bell in counter current contact to said gas to obtain oxygen-enriched water, withdrawing residual gas from said bell, and drawing off the resultant oxygen-enriched water from the bottom of the bell so as to mix directly with the water in the reservoir.