Structures
One of the biggest advantages to the round-tank grow-out model is the ability to cover the tanks with either a shade netting or a greenhouse type of structure for temperature control. Enclosing the grow-out tank allows for temperature and light intensity control. In biofloc or semi-biofloc conditions, reducing sunlight favors the development of beneficial bacteria and biofloc. A lower light intensity also reduces algae blooms (and crashes) and subsequent Vibrio outbreaks.
50% shading over round tanks is the minimum coverage recommended to control algae blooms.
RAS systems can be easily adapted to the round-tank model as shown in this salmon nursery system.
Fixed room or PEB (pre-engineered buildings) are more expensive but more permanent structures to control water quality parameters. These structures could also support solar panels to reduce energy costs.
This is an inovative round-tank structure from Brazil. Tanks as large as 450 m2 can be covered using this type of structure.
Drawing of the Brazilian round-tank structure.
Bac Lieu - this 80 round-tank farm has their Phase 1 nursery tank covered by a fixed roof structure.
Israeli design greenhouse structure....Bac Lieu, VN
Inside of a nursery greenhouse in Brazil