There are many factors to
consider when selecting a tilapia species. Here, in a nutshell, are the main
advantages and disadvantages of each one.
Which tilapia species is best
for aquaculture? This is not as simple as it sounds; the answer depends on
factors such as intended use, culture system and climatic and environmental
conditions. The term ‘tilapia’ refers to all fish of the cichlid family that
resemble the original genus Tilapia. In Southern Africa, naturally occurring
tilapia fall into two genera: Oreochromis and Tilapia. Oreochromis are maternal
mouth brooders, while Tilapia are substrate spawners.
There are two indigenous species of each:
1.
Oreochromis
O.
mossambicus: The Mozambique bream, or blue kurper, is the
best-known tilapia species. It is deep-bodied and occurs in the warmer parts of
South Africa in east-flowing rivers and dams. It has also been widely
translocated to areas such as the Western Cape and Namibia. Red forms suitable
for aquaculture are available. Its limitations include a temperature tolerance
of above 12°C, relatively slow growth and early maturity.
O. placidus: A similar but smaller species, O. placidus is found in the Mkuze swamps and the North-Eastern lowlands extending into Mozambique. It has a different breeding colouration and four anal fin spines, compared with the three of O. mossambicus.
2.
Tilapia
T.
rendalli: The genus Tilapia is represented by T. rendalli and T. sparrmanii.
The former, the well-known red breast tilapia, is restricted to water over 13°C
in winter. Largely herbivorous, it is deep-bodied with a convex forehead
profile. Females have red chests and up to nine vertical bands. Males have
white chests. Red breast tilapia often have a distinct two-tone caudal fin
colouration, red at the base and pale above, with no spotting. They are
robust-bodied and will jump when surprised. This is the tastiest tilapia, but
it grows slowly. The species is popular in aquaponics as it consumes plant
waste.
T. sparrmanii: Vlei kurper or banded tilapia – is the most widespread species in South Africa. It is a good-looking fish, with a deep body and a blunt snout, but it is unsuitable for aquaculture, as it does not grow longer than about 12cm. It is the most cold tolerant of our indigenous tilapia and can survive at 6°C for short periods. It will live through the Highveld winter and have been widely trans-located through inter-basin river transfer schemes.
3.
Non-native Tilapia
The Nile tilapia (O.
niloticus) has been introduced to South Africa for aquaculture as it has the
potential to grow large and rapidly. But only the most carefully selected
strains perform well; many inbred and stunted populations do poorly. The
species is identified by the iridescent spots in the caudal fin. They readily
hybridise with indigenous species.
Species such as O. andersoni
(three-spot tilapia), O. aureus (Israeli tilapia) and O. macrochir (green-head
tilapia) are non-native to South Africa, but have reportedly been introduced in
certain places. O. andersonii has considerable aquaculture potential and is
used in Zambia.
About
the author:
Nicholas
James is an Ichthyologist and Hatchery Owner
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