PASSAGE 12

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PASSAGE 12
TILAPIA
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Tilapia is a genus of warm, predominantly
freshwater fish native to Africa.
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They are robust fish able to withstand high
water temperatures and low level of oxygen.
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Their optimum temperature range is between 20º
to 30ºC they can tolerate temperatures as low as
12ºC.
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Many species can withstand saline water up to
full seawater.
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Tilapia species have biological differences
associated with their feeding and breeding habits
and anatomical differences associated with their
feeding habits.
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These differences have caused systematic to
divide tilapia into three different genera
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Tilapia, example Tilapia zillii.
????????1 ??????? Tilapia zilli
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These spawn in net which they construct in the
pond bottom.
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They guard the young in the net.
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They have coarse teeth and feed on macrophytes.
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Saratherodon, example Saratherodon gillilaeus.
????????2 ???????????? Saratherodon gillilaeus
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These take the eggs and larvae and brood them in
their mouths.
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They have fine teeth and feed on particulate
matter
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Oreochromis, example Oreochromis spilyus
???????? 3 Oreochromis spilyus
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These spawn on the ground but brood the eggs and
larvae in the mothers mouth.
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They have fine teeth and feed on filamentous and
unicellular algae.
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Tilapia are fast growers under good condition,
reaching 150 g in weight in 10 months
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Wild tilapia can grow to be large fish reaching
sizes of 1,300 g
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Tilapia become sexually mature at an early stage
in their development when they reach a size of
about 15 cm generally at about six months old.
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??? 15 ????????? ??? 6 ???????????
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After reaching maturity they spawn every six
weeks.
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This high fecundity of tilapia has caused the
major problem in tilapia farming which is the
problem of over population of the pond
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This means that food becomes in short supply and
fish can not grow
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This in turn means that the farmer when he
harvests pond collects a large population of
small fish often too small to the market.
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