Tilapia Growth Graphs
order to make best use of these
characteristics.
In commercial fish farming, the following are the principal technique
applied in order to obtain mono-sex
populations:
Hormonal sex reversal of fry,
Hybridisation through interspecies breeding,
Genetic manipulation
Culture systems of tilapias in the
world are very diverse, perhaps the
most diverse among all aquaculture
species in the world. It is a group of
fish that could be cultured at many
desired intensities, thus, appealing
to all socio-economic strata, enabling the culture practices to be
adjusted to suit their economic capabilities.
Temperature as environmental
factor influencing tilapia production:
The optimum water temperature
for growth is 24 to 32 ˚C. Some
people have the opinion that you
cannot farm tilapia in an economically feasible way in South Africa
because of our cold winters. I tend
to differ. I believe that by using
technology, innovation and common sense we would be able to
overcome this challenge. There are
15 countries in Europe producing
tilapia today and there is even a
tilapia farm in Siberia where it is a
lot colder compared to SA. We
need to warm the water in a cost
effective way. Climate conditions
for trout is also not ideal but we
manage to produce 1 000 ton of
trout every year in this country.
Processing and yields:
The yield of the gutting operation
varies between 88 to 92 %. In other words, 8 to 12 % of the body
weight of the fish constitutes the
offal (O.niloticus). This is obviously
an important element to include in
the calculation of production
costs.
Filleting yields for tilapia is relatively low. For skin-on fillets, a 40 to
42 % yield can be obtained. For
skin-off fillets, some 33% can be
achieved if the filleting is done by
hand (only 30 % if a machine does
the filleting). Once again, yields
Market-size Tilapia
are variable following fish size and
species.
The local market:
Tilapia’s reputation in tropical countries does not need any major promotion; the fish is well distributed
and commonly accepted as a preferred fresh water fish. However,
prices are very variable according to
the country. There is not a formal
m arket for this fish in South Africa
7.4 kg Nile Tilapia