Tilapia is the common name for nearly a hundred species of cichlid fish from the tilapiine cichlid tribe. Tilapia are mainly freshwater fish, inhabiting shallow streams, ponds, rivers and lakes, and less commonly found living in brackish water. Even the Ancient Egyptians farmed tilapia in ponds along the Nile and small scale tilapia farming is still an important source of protein for many families around the world. Large scale commercial farming can be problematic due to the rapid production of offspring that will compete for food with the adult fish, but several techniques have now been developed to combat that problem. The fish can for instance be kept in densely stocked tanks or cages, since this disrupts reproduction in tilapia. When tilapia is cultivated in ponds, it is common to keep male fish only to avoid unwanted offspring.
Large-scale commercial culture of tilapia is limited almost exclusively to the culture of three species: Oreochromis niloticus, O. aureus, and O. mossambica. Of the three tilapia species with recognized aquaculture potential, the Nile tilapia, O. niloticus, is by far the most commonly cultured species in tilapia farming. The use of hybrids of 2-4 species of tilapia is also quite popular in certain countries.
Growout strategies for tilapia range from the simple to the very complex. Relatively simple tilapia farming strategies are characterized by little control over water quality and food supply and by low fish farm yields. As greater control over water quality and fish nutrition is imposed and fish stocking levels are increased, the fish yield per unit area increases. Across this wide range of fish farming methods, there is a progression from low to high management intensity.
In traditional pond culture of tilapia, proper environmental conditions are maintained by balancing the inputs of feed with the natural assimilative capacity of the pond environment. The pond’s natural biological productivity (algae, higher plants, zooplankton and bacteria) serves as both a food source and a biological filter that helps convert fish waste by-products through natural biological processes. Increasing fish stocking densities places increasing demands on the fish production system. Additional energy inputs in the form of labor, water exchange, aeration and higher quality fish feeds are all required to sustain fish culture conditions in the intensive system. As pond production intensifies and fish feeding rates increase, supplemental aeration and some water exchange are required to maintain good water quality. For fish stocking densities above 1.5-kg per square meter, aeration is usually required. Eventually, there is an end point where the incremental returns on investment are not worth the incrementally higher rated of production relative to the higher costs and higher risks. In other words, increasing the intensity of the fish culture system does not necessarily reflect an increase in profitability.
All tilapia production systems must provide a suitable environment to promote the growth of the aquatic crop. This is true regardles of whether tilapia are grown in ponds, in cages, or in tanks or raceways. Critical environmental parameters that must be properly managed include dissolved oxygen, ammonia, nitrites, and carbon dioxide. Other important parameters to control within the fish productoin system include nitrates, pH, and alkalinity. To produce tilapia in a cost effective manner, aquatic production systems must be capable of maintaining all of these water quality variables in a safe range for the entire grow-out period.
Proper feeding of a nutritionally balanced fish feed is critical to success for any tilapia farming operation. To produce excellent growth rates, tilapia are typically fed moderate to high protein pelleted diets at rates ranging from 1.0% to 30% of their body weight per day depending upon their age and size.
Numerous options for holding broodfish, fry, fingerlings, juveniles, sub-adult and adult tilapias are available to the prospective farmer. The basic options include ponds, tanks or raceways, and cages. Ponds are used in extensive, semi-intensive and intensive tilapia production. Pond culture is by far the most common method being employed on a global scale because it is one of the cheapest methods and also is one of the best. Ponds are much cheaper to construct and allow tilapia production specialists to stimulate natural productivity more readily. One potential major drawback of pond culture is the greater risk of uncontrolled reproduction, which will occur if the tilapias have not been properly sex-reversed prior to stocking in the grow-out ponds. Tanks or raceways involve considerably greater expense to construct, but offer greater control. They are typically used in intensive growout of tilapias, or in the tilapia hatchery. If it's done right, cage culture of tilapia can be the least cost method of growing larger tilapia, but tilapia cage culture is limited by availability of high quality sites and can be subjected to potentially devastating environmental extremes if not prpoerly acounted for in the site selection and operational plans.