Aqua Africa News: Tilapia Breeding options available

Some populations of animals all breed at the same time, producing young simultaneously to overwhelm predators or make use of a limited optimal season for the growth of the young.  This includes mammals such as impala, birds such as puffins and fish such as salmon.  Other creatures do not synchronise their spawning as they normally live in climates that are conducive to year-round breeding, including animals such as elephants and fish such as tilapia. Aqua Africa has written a blog post regarding these opportunities for your reading pleasure.

From a commercial farmers’ perspective tilapia are of the easiest of fish to breed; simply hold them under the right conditions of water quality, lighting, feeding and population structure, and they will breed semi-continuously.  However, this means that you have a dribble of eggs and fry being produced continuously, which is not ideal as you need to keep similar sized fish together, and this slow flow of fry means you need many replicates of small tanks or ponds.

Tilapia farmers generally use 1 of 2 possible approaches to breeding their fish.  The basic method is to hold the breeders under good conditions and allow them to mate and incubate the eggs in the breeding tank.  When the farmer notices fry swimming around the sides of the tank these are netted out.  This method is favoured for its simplicity but is very inefficient in terms of the number of fry produced by a group of breeders.  A more successful and therefore widely used technique involves harvesting the eggs from the females every 7 days and incubating the eggs artificially.  This is far more productive than the previous method but does require a little extra effort and infrastructure.

Both of these traditional approaches are successful but result in asynchronous spawning and many small batches of fish to work with.  In addition, because the males and females are constantly or frequently together (commercial farms rest the females away from the males for part of the time), each female tends to be underproductive.  We have successfully trialled synchronising the spawning of our tilapia by keeping the sexes apart for most of the time.  Once a month the breeders are placed together and a mass spawning results involving most of the females.  After 7 days the eggs are removed for incubation, sexes are again split and the females have 3 weeks in which to recover their energy and built an egg supply.  This method produces greater quantities of fry from the group of breeders, and critically they are all within a few days of each other so you have them as a single large group, making downstream logistics far simpler.  

Tilapia are naturally asynchronous spawners but coordinating them to spawn within a few days of each other results in greater output and increased efficiency.