What is Biofloc fish farming?
Aquaculture as an activity is constantly growing and maximizing resources and spaces is an important aspect. This is why different technologies have been worked upon. These technologies seek to resolve the main problems that can be found in factory farms. One of these technologies that can be found in a more prevalent fashion is the Biofloc technology.
The Biofloc system has allowed aquaculture farms to reduce water exchange while providing added value to the products resulting from microbial metabolism. Biofloc technology (BFT) is a technique that removes waste created by aquatic animals and provides nutrition to aquatic animals.
Biofloc Technology (BFT) allows continuous recycling and reuse of nutrients in the culture medium, by minimum water exchange. Due to this reason, BFT is considered a new “blue revolution”. It is a sustainable and environmentally friendly aquaculture technique as it is based on in situ microorganism production. Under the BFT system, wasted feed along with fish excreta in the water ecosystem, is converted into feed that can be consumed by the fish. The combination of microorganism, fungi, algae and so on forms a Biofloc which enhances the quality of water by absorbing inorganic waste. Therefore, resolving the issue of water pollution. This also enables the fish farmers to save funds on feed due to its ready availability.
In a populous country like India where there is a rise in population every day the demand for aquaculture also rises with it. The Indian subcontinent contributes a whopping 6% to global fish production and more. However, the expansion of aquaculture is limited primarily due to two factors: first, it puts pressure on the environment by discharging waste materials into bodies of water, and second, it is dependent on fish oil and fish food.
Biofloc technology can help resolve these problems because it is a profitable method of intensive fish farming that controls water quality and produces proteinaceous feet in situ. Biofloc acts as a wastewater treatment method that also feeds aquatic animals.
The fact that little to no fishmeal is used in traditional methods of fish farming and farmers supply nutrient-rich material to the water to enhance the growth of algae and other organic matter on which the fish feed, served as an inspiration for researchers to Biofloc technology; where nitrogen is waste generated by the cultivation of organisms and is converted into bacterial biomass. This is why this system is needed as the Biofloc system fits in this situation as an affordable technology. It converts toxic materials into useful products, serves as a nutrient retention belt in the pond, and lowers maintenance costs.
Biofloc technology contributes to a reduction in water pollution by a lot and also limits the risk of introduction and spread of pathogens. BFT reduces the utilization of protein-rich feed along with the cost of standard feed and increases productivity. Thus, Biofloc technology keeps the water quality high and results in a great production of fish.
How does Biofloc system work and its profitability
This Profitable Method of Fish Farming is carried out in a tank of various sizes. The most common size is four inches in diameter. In a culture system exposed to sunlight, Biofloc technology converts unused feed and aqua animal faeces into food, resulting in a protein-rich live feed. Feeding costs are reduced by converting excess into food again.
Biofloc is primarily composed of heterotrophic bacteria. It lowers the amount of ammonia and nitrite produced by fish feeding. These Heterotrophic bacteria eat Ammonia and convert it into protein. This can then be consumed by fish to help them grow. It functions as actual feed for the fish. It also has a good nutritional value.
Biofloc Farming eliminates all major costs, allowing for significant savings. Several factors, including high operational costs, the cost of vast lands, and the high costs of feeding, disposal, and discharge of waste sludge, will not be an issue if this method is chosen.
Feeding ingredients for fish are the most expensive aspect of aquaculture. When fish are fed high protein diets, approximately 70% of the protein is excreted as waste in the surrounding culture water in the form of nitrogen. We can recycle this waste into feed again using Biofloc, lowering the cost of high protein feeds.. Biofloc systems also reduce the spread of pathogens while also improving the fish health
Requisites for Biofloc farming
Step 1: Setting up the pond or tank:
Finding a location to set up the pond or tank is the first thing that is to be done. During this stage one needs to be mindful of factors like sunlight, temperature and ventilation Keeping in mind that the majority of contaminants enter the water through the soil at the pond bed. Make sure that the pond is lined with a protective layer/ lining of concrete. This issue can be remedied by opting for a tank over a pond
Step 2: Aeration:
Installation of aerators is the second most vital step in this system. Aerators are responsible for maintaining the entropy of the suspended particles of algae, bacteria, protozoa, etc. which are the food for the fish. It also maintains the proper oxygen distribution throughout the tank/ pond and prevents the formation of anaerobic zones that can contribute to the formation of methane and ammonia. Formation of methane and ammonia can cause the mixture to smell, thus resulting in the degradation of the harvest quality. Hence, installation of aerators can directly affect the quality of produce.
Step 3: Species selection and related things:
After setting up a proper aeration system one can move on the selection of species. Due to the improved water quality in a Biofloc system, almost all species of fish can be cultivated easily. In order to make this decision simpler, one can also seek guidance from established experts in the fish farming field
Step 4: Optimization of Carbon and Nitrogen:
One of the most important requirements for Biofloc formation is that the carbon and nitrogen ratio in the culture system be maintained. The C:N ratio should be between 10:1 and 20:1 for the development of Biofloc. Manipulation of the C:N ratio can improve water quality by utilising nitrogen and regenerating new bacterial cells, thereby reducing waste effluent from the culture system.
Step 5: Biofloc growth:
After following through with the above mentioned stages, comes the time to begin cultivation. In this stage seeds for different algae, bacteria, protozoa, etc are added into the culture system along with a few probiotics to ramp up the process. Within a matter of weeks the number of flocs would reach from almost negligible to four to five flocs per millilitre.
One can keep track of floc growth by using a cone-shaped beaker or a flask and collect several water samples at a depth of 15cm to 25cm, preferably late in the morning. The solid particles will take over 20 minutes to settle when left undisturbed and then will get stuck to the sides of the container therefore making it easier to count them
Step 6: Monitoring, Harvest, and Clean-up:
Samples of water from the pond/tank must be taken on a regular basis to monitor the activity of the two Biofloc types and determine their density. As the stock grows and the feeding volume increases, the water will reach a tipping point and turn brown. To maintain a high respiration rate once the Biofloc system has turned brown, aeration must be significantly increased.
The water should be monitored regularly, especially to determine the levels of dissolved oxygen and ammonia. This gives an idea of how well the entire system is working. Regular monitoring of the performance of the farm stock, calculating and recording growth rate, overall appearance, FCR, and stock survival is also required.
Conclusion
Finally, after harvesting, proper cleaning and preparation of the pond setup or raceway is critical. Although it may appear appealing to reuse the culture water because it took a significant amount of effort to build up the populations of microorganisms, this is not recommended. Pathogens may have accumulated in the culture, posing a serious biosecurity risk. According to research, heavy metals can accumulate in culture water over time, contaminating your stock and rendering it unfit for human consumption.
