If you live near even a small waterway, a Raceway system could be the simplest system for getting your new fish farm started quickly.
Raceway aquaculture, or a flow-through system, uses a continuously running source of water and is a profitable method of raising fish. Many farmers around the world have used this method where water is sourced from a stream or spring and made to flow continuously through man-made canals or channels into purpose-built ponds.
In this system, full utilization of water and resources is possible. The natural flow of water in many cases eliminates the need for pumps and filters.
Freshwater species for Raceway culture systems
You can obtain a variety of species of eggs for your hatchery or begin with juvenile fish, but cold water species are best for this type of system.
In a Raceway system, the water source is generally colder than lake or river water because it comes from streams or springs flowing downhill. This water usually comes from melted ice from mountain peaks. Moreover, the movement cools the water during transit and, therefore, a variety of cold water species are suited for this system.
Some of the most common coldwater raceway farmed fish include the following:
- Rainbow trout
- Freshwater shrimp
- Juvenile Salmon
Raceway structure and construction
Raceway ponds and channels are designed in such a way that no water is stagnant at any time in the fish pond. If the water stops flowing, it collects dirt, debris and feces, which may become toxic for the fish, or may cause diseases.
A running water source maintains the water quality and oxygen level of the fish tank.
Of course, choosing the location of the farm is essential in this system due to its dependence on running water. You can locate your farm across the water source or along-side, to control the flow of water in the raceways.
Artificial Raceway system
If you don’t live near a natural water source, don’t stop reading, as you can create a similar flow artificially by using your municipal water supply with a pump.
A recirculating system with filtration and aerostation systems (which add oxygen to the water) are needed when artificial flow of water is used, but don’t worry. These really are standard requirements of most fish farming.
Construction of Raceways
Typically, the raceway canals can be made with concrete, but other materials are also sometimes used. For example, some countries in Asia use mud, wood, stones or fiberglass to construct the raceways.
Types of flow-through systems
Flow-through systems depend on an abundant and continuous flow of water. There are two types of flow-through systems.
- Conventional Flow-Through Systems: In the conventional system, oxygen requirements of fish are supplied by the water flow.
- Intensive Flow-Through Systems: In an intensive system, an aerator is used to supply additional oxygen for the fish.
Raceway pond sizes
Ponds can vary in size depending on what they are being used for. For fry culture, smaller sized ponds are used. For production and marketable sized fish, a larger pond is necessary.
It also depends on how many fish you plan on raising and keeping in your pond. Generally speaking, 100 feet long and one foot to about three feet deep ponds are fine for fry production, with a canal width of about five feet. You can increase the depth for marketable sized fish.
A number of canals can run simultaneously with no added energy required for water to flow. Water can flow naturally with the current or by force of gravity.
Silos are needed if you decide to include a hatchery with your farm. If you decide to buy juvenile fish, you can grow them in your canals, and no silos are necessary.
If you do decide to include seed production/fry cultures in your operation, these silos can vary from 5 to 30 feet in diameter, depending on the fish you wish to culture. They should have a 10% bottom slope to remove solid waste before water is discharged. The water from inlets is designed to be a driving force to circulate the water in the silo, allowing the solid waste to be removed through the outlet located in the center of the silo.
Overall System operation
Due to the depth of the canals and ponds, fish have less access to oxygen and tend to produce more waste than normal farmed fish as they grow, and so the pond size has to be increased as the fish grow bigger. The water quality also needs to be kept to the optimum level. You will need to circulate water through the system more frequently for the marketable sized fish.
Your system may also need the following:
An aerostation: In the event that the incoming water quality is low and there isn’t an adequate concentration of oxygen, an aerostation method should be used.
Removal of solid waste: Solid waste spoils the bottom water quality, and so, water should be continuously cleaned. A pump can be used for directly sucking the solid matter out from the bottom.
Waste water treatment: Water can be treated, purified, and reused in the system, or added back to the natural water source to be filtered naturally.
Production levels of your farm depend on how closely you monitor and take care of your fish.
Raceway fish need to be fed regularly. The amount of food and supplies will depend on the type, size and the amount of fish you have. Having a recirculating system with no outflow from your farm will reduce water waste and environmental impacts on the surrounding bodies of water.
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Source: WorldWide Aquaculture