First published in International Aquafeed, July-August 2015
Originating from the lakes of Eastern, Central and Western Africa, the Nile tilapia (Oreochromis niloticus) was first introduced to developing countries as a cheap, easy way for subsistence farmers to provide their families with enough protein. With improved production techniques and methods of controlling its flavour, the fish became more of a mainstream product. Communities of migrants from these countries then created a market for tilapia in the developed nations they had moved to, and finally a taste for the fish spread amongst the locals.
With a mild, unintrusive flavour, Nile tilapia lends itself readily to a wide range of dishes and cuisines. It’s pretty adaptable from the farmer’s point of view, too. Omnivorous yet predominantly vegetarian, tilapia grow quickly on a diet lower in protein and higher in carbohydrates than that required by many carnivorous farmed species. They are also relatively resistant to disease and poor water quality, and they breed easily.
Keeping mixed-gender groups in ponds can result in lots of stunted offspring competing for food and space. There are two main ways to fix this. You could try sex-reversal. Administering hormones in their feed at an early stage ensures the fish all grow up as males. This has an added benefit, owing to the fact that males of this species grow twice as fast as females.
Alternatively, you could continue to raise them in mixed-gender groups, but in cages. Nile tilapia need a bowl-like depression in a sandy substrate in which to fertilise their eggs and from which to gather them up in their mouths to brood them. In a cage, even if any eggs do get fertilised, they will simply fall through the mesh and be lost. Being both easier and cheaper than sex-reversal, the cage method is employed across China, Indonesia and much of Central and South America.
Source: FAO
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