Article and photos by Henk Stander
Animal husbandry depends on meeting the food and environmental requirements of the species concerned in a protected environment in order to realize
enhanced survival and growth compared with that which would be obtained by
harvesting from the wild.
I
n Recirculating Aquaculture
Systems the water flows from a
tank (s) to a treatment process
and then is returned to the
tank, hence the term recirculated or
recirculating aquaculture systems.
Recirculating or closed water systems continue to be used primarily
for experimental work and for the
rearing of larval organisms in commercial and research facilities,
though
increasingly;
profitable
commercial applications are being
demonstrated.
There is a great deal of interest in
recirculation aquaculture production systems both in South Africa
and worldwide. Most fish grown in
Broodstock Tanks
ponds, floating cages, or raceways
can be reared in commercial scale
recirculation systems, but economic
feasibility of doing so is not certain.
Recirculation systems are generally
expensive to build and require a lot
of energy to run which increases
production cost.
Environmental Conditions:
The climate in South Africa ranges
from desert and semi-desert in the
north west of the country to subtropical on the eastern coastline.
Temperatures are also quite extreme between summer and winter,
it is getting quite cold (-5 to 10 degrees Celsius) in winter (MayAugust) at night and it is pleasantly
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warm and sunny in spring and autumn, and often hot in summer
(November to March) with frequent
rains to cool things down. The day
temperatures in summer are normally averaging between 25 to 35
degrees Celsius.
The African continent is particularly
vulnerable to climate change. In
fact, with 80% of the African population dependent on agriculture for
their livelihoods, it could cost as
much as US$ 50 billion a year for
Africa to adapt to the effects of climate change. Moreover, climate
change could also mean a 50% decline in jobs related to fisheries.
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