Modular buoyancy system and flotation element for net cage

A buoyancy element for constructing a modular buoyancy system for a circularly shaped net cage, wherein the buoyancy element comprises a cage side, an opposite straight long side, and coupling sides between the cage side and the straight long side, wherein the cage side is curved and follows configured to follow a periphery of the net cage, and wherein the straight long side and the coupling sides are each provided with a projection in which a connecting unit is positioned;

• and a passage with a first mouth on the cage side and a second mouth on a top side.

A facility for aquaculture which includes a plurality of net cages, wherein each net cage is kept afloat by a modular buoyancy system wherein at least one module of the modular buoyancy system comprises a buoyancy element having a cage side, an opposite straight long side, and coupling sides between the cage side and the straight long side, wherein the cage side is curved and follows a periphery of a circularly shaped net cage, wherein the buoyancy element is one of a plurality of buoyancy elements that are connected to each other along coupling sides in a number encircling the net cage and wherein the modular buoyancy system is one of a plurality of modular buoyancy systems which are connected along the straight long sides of adjacent buoyancy elements therein.