Aquaculture Nitrogen Cycle

Aquaculture Nitrogen

Understanding the Nitrogen Cycle and Water Chemistry is Fundamental to Aquaculture Success!

The nitrogen cycle pertaining to aquaculture is a vital chemical process in both fish culture ponds and in particular to intensive Recirculating Aquaculture System (RAS) tank culture.

As a live-stock farmer is concerned with optimising the management of pastures to maximise sheep and cattle production, aquaculture producers need to optimise the culture of bacteria with the prominent role of converting toxic nitrogenous wastes into relatively harmless waste compounds. Producing fish within intensive tank systems also need to effectively become beneficial bacteria farmers.

Aquaculture Waste

Waste water from both pond and tank aquaculture production methods is a valuable commodity. This ‘waste’ resource is an exceptional fertiliser, sometimes requiring minimal nutrient additions, that is ideally beneficial for plant crop production.

Solid wastes that are normally removed from ponds, when they are periodically drained to allow disinfection from the Sun’s ultraviolet radiation, is an effective soil conditioner and fertiliser. Both pond and tank fish culture methods necessitates regular but relatively minute water exchange rates. To remove the build of nitrates, for example, as little as five percent of water is drained away, to be topped up with freshwater. This exchanged water, under Australian aquaculture permit conditions, requires to be drained to effluent settlement ponds.

However, it may as an intermediate process, be passed through irrigated crops to aid in fertilisation. Large aquaculture pond operations have been recorded to reduce rice production fertiliser costs by up to seventy percent. Irrigation of agri-forestry has significantly accelerated tree growth rates. And exceptionally impressive is the use of aquaculture waste water for hydroponic production of various vegetable and herb products.


The next evolution of aquaculture production is the utilisation of fish waste resources to produce fish feed products, such as lupins, and help generate a truly holistic approach to a sustainable aquaculture industry.


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