Tilapias are the preferred fish and the national dish in Malawi. A substantial market exists for producers capable of providing whole fish more competitively than dressed broiler chickens, less than a cost of US$2.40/kg (R33.00/kg) in the country. Under favorable economies of scale and scope, tilapia production using biofloc technology represents an attractive investment proposition if that selling price can be matched.
Biofloc Technology (BFT) is a relatively new and potentially revolutionary technology that is especially productive for tilapia and shrimp aquaculture. BFT is a sustainable and environmentally-friendly method of aquaculture that controls water quality and harmful pathogens along with providing value-added production of microbial protein feed for the aquatic farm system. Bioflocs are clustered aggregations of microbial communities such as phytoplankton, bacteria, and living and dead particulate organic matter. Shrimp and tilapia especially benefit from BFT due to their ability to filter-feed on floc in the water column, thereby reducing feed costs by improving feed conversion.
The beauty of BFT is in the mechanisms for ammonia removal from water. Using feeds with a carbon to nitrogen (C/N) ratio greater than 15 results in the dominance of heterotrophic bacteria as the major pathway for the removal of toxic nitrogenous compounds via assimilation into new bacterial cell biomass. BFT simultaneously provides an abundant source of “bacterial plankton” and a rich source of good-quality protein and nutrients for filter-feeding fish and shrimp — BFT is then rather like killing two birds with one stone.
Experience raising tilapia in BFT, where feeding rates per unit area are at least 4 to 5 orders of magnitude greater than shrimp BFT systems, is limited. Knowledge gaps remain about BFT engineering economics, tilapia feeding systems and bioenergetics, cost factors and the economics of this new technology relative to conventional tilapia aquaculture systems. Insightful experience gained at Chambo Fisheries fills many of these knowledge gaps.
Source: World Aquaculture Society // Original Article
