Water management is a critical aspect of successful fish farming, as the quality and availability of water directly impact the health and growth of the fish. There are several water management systems used in fish farming, each with its own advantages and disadvantages. In this article, we will explore the different water management systems and their key features.
Flow-through System
The flow-through system is a water management system in fish farming where water is allowed into the pond through an inlet pipe(s) and the used water is released into a water body to keep the pond refreshed. Sometimes, the water coming into the pond may be treated or may not be treated, depending on the water source and the farmer’s preference.
The main reason for setting up a flow-through system is to limit water pollution and its effects. In areas where water is scarce, the used water from the ponds is re-used by allowing it to settle down in a settlement dam or tank.
Merits of Flow-through System
Simple to set up
Low setup cost
Easy to maintain
Low cost of maintenance
May not need electricity to operate
Can be handled by people with little or no training
Demerits of Flow-through System
Can only be efficient where water is available in good quantity
If the inlet water is not treated, infections can find their way into the pond
Not effective in the dry season
Water can be polluted through the supplying source
Pipes can be blocked by unscreened particles
It could be at risk of flooding when the inflow of water is not controlled during rain
The temperature of the pond depends on environmental conditions
Recirculatory System
The recirculatory system, also known as the recirculation aquaculture system (RAS), is a water management system in fish farming where used water is treated for re-use. This system is made up of a closed or partially-closed system of indoor water management techniques, where the used water is treated for chemical, gaseous, biological, and solid waste before being re-used.
The system controls the pH and water temperature to ensure a conducive environment for fish growth. A complete recirculatory system may comprise the following components: a tank, a screen or sand filter, other filters, aerators or oxygen pumping machines, submerged heaters or chillers or heat exchangers, and linking pipes.
Merits of Recirculatory System
Promotes efficient water management by ensuring limited water resources are used judiciously
Ensures economy of land due to its high-density stocking capability
Is environmentally friendly as the used water is treated before being released into the environment
Reduces the risk of infections and diseases by controlling the water quality parameters
Demerits of Recirculatory System
Expensive to set up
High cost of maintenance
Can only be handled by trained personnel
High cost of operation
Breakdown in any part of the system will affect the entire system
Cannot be operated in the absence of electricity
Pond/Stand-Still System
The pond or stand-still system is a static system of water management where the pond water is rarely refreshed through an external source. This system is not as common as the flow-through or recirculatory systems, as it has limited water management capabilities.
In summary, the different water management systems in fish farming are:
Flow-through System: Water is allowed into the pond through an inlet pipe(s) and the used water is released into a water body to keep the pond refreshed.
Recirculatory System: Used water is treated for re-use, with the system comprising various components like filters, aerators, and temperature control devices.
Pond/Stand-Still System: The pond water is rarely refreshed through an external source, making it a static system with limited water management capabilities.
The choice of the water management system depends on factors such as water availability, budget, environmental regulations, and the farmer’s expertise. Careful consideration of these factors is crucial for the success and sustainability of a fish farming operation.