The key role of oxygenation in aquaculture and a guide for selecting propeller-type aeration equipment
Why are aeration systems indispensable in shrimp farms?
In aquaculture, aeration is a crucial component for maintaining the ecological balance of the water body. Most biological processes in water – from the respiration of shrimp to the microbial decomposition of organic waste (such as leftover food and feces) – rely heavily on the continuous supply of dissolved oxygen. If the dissolved oxygen is insufficient, shrimp may experience reduced feeding, weakened immunity, and in severe cases, massive surface floating or even death.
Under natural conditions, the diffusion of oxygen from the air to the water body is extremely slow. In stratified water bodies (especially during the summer heat period), a temperature gradient forms between the oxygen-rich surface water and the oxygen-poor bottom water. It often takes several hours or even longer for oxygen to reach the bottom of the pond, and shrimp are particularly bottom-dwelling organisms, making the risk of oxygen deficiency particularly prominent.
More importantly, the biological density in aquaculture ponds is far higher than in natural environments. High-density stocking and the large input of high-protein feed lead to an exponential increase in the oxygen consumption rate of the water body – not only does the shrimp population itself consume oxygen, but the rapid oxidation and decomposition of a large amount of organic matter also sharply consume dissolved oxygen. Therefore, relying solely on natural reoxygenation is far from sufficient; mechanical aeration equipment must be used to forcibly increase oxygen levels, in order to support high-yield aquaculture and accelerate the oxidation decomposition of metabolic waste, maintaining stable and healthy water quality.
When should aeration be initiated?
The core judgment basis for aeration initiation is dissolved oxygen concentration. When the dissolved oxygen in the water drops to the critical value that causes stress to the breeding objects (typically below 70% of saturation), it is a signal that aeration is necessary.
The hazards brought by low oxygen environments are systemic:
Growth inhibition: During hypoxia, shrimp shift their energy metabolism to anaerobic pathways, resulting in a decrease in feed conversion rate and stunted growth;
Reduced disease resistance: Long-term exposure to low-oxygen stress suppresses the immune function, significantly increasing susceptibility to diseases;
Reproductive disorders: Insufficient oxygen can affect gonad development and the survival rate of larval shrimp.
It is particularly important to note that different shrimp species have significantly different tolerance thresholds to low oxygen (for example, the asphyxiation point of the South American white shrimp is approximately 1.0-1.5 mg/L, while that of the spotted shrimp is slightly higher). Therefore, the most reliable management strategy is not to start aeration until the critical value is reached, but to maintain dissolved oxygen at a safe range of 70% or above based on oxygen monitoring data, preventing problems before they occur.
How much of the pond can a propeller-type aeration machine cover?
This is a question that farmers often ask but is also difficult to provide a “standard answer”. The reason is that the effective coverage area is not determined by the equipment itself, but is the result of the combined effect of multiple dynamic variables, including:
| Variable Category | Specific Factors |
| Stocking Parameters | Shrimp species, size/age class, stocking density, feeding rate |
| Water Quality Parameters | Water temperature, salinity, water depth, pH value |
| Environmental Parameters | Solar radiation intensity, cloud cover, wind speed and direction |
| Management Parameters | Fertilization regime, water exchange frequency, sediment/bottom condition |
These factors are not only difficult to quantify precisely, but also fluctuate continuously throughout the entire breeding cycle – the same paddle-wheel aerator may have a different oxygenation effect in a cold and lean water body compared to the effect during the high-temperature and high-density feeding period, with the difference possibly being several times.
In practice, the most reliable selection logic is not the “area coverage method”, but the “yield matching method”: the higher the target yield of the pond, the greater the total oxygen consumption in a unit of time, and the greater the required oxygenation power. Industry common experience is that for every 1 ton of shrimp produced, approximately 1.0 to 1.5 kW of paddle-wheel aerator power is required, but the specific value still needs to be flexibly adjusted in combination with the above variables.
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