Propagation and fingerling production
Tilapia fish breed very easily in breeding ponds. Adult fish will begin mating soon after they are released into ponds, provided that the water temperature is between about 25 and 30 °C.
Feeding – The fish should be in good condition before being stocked to the pond. Only some feed, preferably high in protein and fat, is needed for the fish in the breeding ponds, as the females do not eat during the breeding phase. The breeding ponds can be fertilized like the big ponds to enable the development of food organisms for the adult fish and the young fry.
Harvesting – Females weighing 700 g or more will spawn about 1200 to 1500 eggs, which results in about 1000 juveniles per female fish. The first harvest of juveniles is possible three to four weeks after stocking using a small mesh-sized net. Harvesting is repeated every one or two weeks. Only juveniles that do not pass a 1 cm mesh are harvested. Every four to six weeks all juveniles need to be caught out of the breeding pond and the smallest must be sorted out and killed. A humane method of killing them is by throwing them into iced water.
Nursing – Fry that is big enough, are transferred to small and shallow nursery ponds where they feed on natural pond production. That is why the nursery pond needs to be fertilized like the breeding ponds to enable the development of feeding organisms for the young fish. The additional feed can be given at a daily rate of 4 to 10 % of the bodyweight until the fish are about 20 to 30 grams. Weighing the fish once a week is needed to calculate the amount of feed necessary. The stocking density of a nursery pond could be about 300 to 500 fish per m². The density depends on the amount of feed and water that is available. When the fry have developed to fingerlings of about 10 cm in size, they can be transferred to the grow-out ponds. During growth in the nursery pond, the smallest fish need to be sorted out every three to four weeks. At the end of the nursing period, they can be differentiated between male and female sex to achieve mono-sex cultures. Forty female fish in a standard breeding pond will produce approximately 20,000 fry per month, leading to at least 3,000 to 6,000 fingerlings.
Q: Is the production of fingerlings for sale to others a realistic aquaculture option?
A: If they can be proven to be of superior quality, available in sufficient quantity and at an affordable price, yes. There is a need for the production of quality fingerlings, and the aquaculture industry cannot start without this reliable source of ‘seed’. There is considerable potential for the production of mono-sex tilapia, red-colour forms of tilapia and even possibly Nile tilapia and catfish fingerlings; however, this form of aquaculture is technically demanding.