WHAT IS BIOFLOC?

Biofloc is the use of aggregates of bacteria, algae, or protozoa, held together in a matrix along with a particulate organic matter to improve water quality, waste treatment and disease prevention in an intensive aquaculture system.

HOW DOES BIOFLOC SYSTEM WORK?

We feed protein-rich feed to fishes. Fish release the faecal matter. Feed waste & other organic residue accumulates which creates toxic gasses like ammonia. Carbon source is added, mixed & aerated. Ideal condition is created for the development of Heterotrophic bacteria. Dense hypertrophic bacterial community is created by C: N ratio manipulation, the system becomes bacterial dominated. Dense bacteria formation lead to forming of floc. Bacteria control water quality by assimilating nitrogenous waste. Fish eat protein-rich bacteria (Floc) reducing the fish feed cost. This is the way by which the whole system of BFT (Biofloc Technology) works.

ITEMS NEEDED FOR BFT SYSTEM :

Tank ,Air pump, pipe ,Air controller, ph, salinity, TDS, DO, temperature meters , Ammonia & Nitrate test kit ,Probiotic bacteria ,Chitagur, raw salt, calcium carbonate. ,IPS/Generator/Solar panel

WHICH FISHES CAN BE USED?

• Tilapia
• Pangasius
• Desi Mangur
• Singhi
• Koi
• Shrimp

SEEDING & HARVESTING TIME:

In winter no seeding & harvesting activity should be done, as the temperature drops & the risk is high. We can seed fishes at different months to get harvest throughout the 9 months. We have to select fishes that will be 1kg biomass or marketable size & harvestable within 6 to 7 months.

THE PROS & CONS OF BFT:

THE PROS OF BIOFLOC:

1. The flocs themselves are protein-rich & provides fish & shrimp with a good source of vitamins & phosphorus.
2. Improved water & land use rates
3. Improve growth rates in the cultured species
4. Decrease mortality rates
5. Improves biosecurity which is not the case of conventional methods.

THE CONS OF BIOFLOC:

1. Increased energy requirement for mixing & aeration.
2. Startup time required.
3. Alkalinity supplementation required.
4. Increased pollution potential from nitrate accumulation.

IS BIOFLOC SUCCESSFUL IN BANGLADESH?

The traditional way of fish farming comes with its demerits like time consumption, dependence on nature, harmful effects on the environment, and not enough fulfilment of demands. So many of Asia’s top shrimp industries are successfully shifting to the Biofloc technique, especially in Bangladesh as it is possible to cultivate 10 to 20 times more than traditional methods or any other process. As Bangladesh has many ponds & rivers, Biofloc fish farming is a very profitable & economical method & has enormous potential here.

Mubashshira Mahmud Meem

Student Of Agriculture; Sher-e-Bangla Agricultural University.