3. The Nile tilapia (O. niloticus) was
one of the first fish species cultured.
Illustrations from Egyptian tombs
suggest that Nile tilapia were cultured
more than 3,000 years ago.
Tilapia have been called Saint
Peters fish in reference to biblical
passages about the fish fed to the
multitudes. The Nile tilapia is still
the most widely cultured species of
tilapia in Africa.
4. During the last half century fish farmers throughout the
tropical and semi-tropical world have begun farming
tilapia. Today, all commercially important tilapia
outside of Africa belong to the genus Oreochromis , and
more than 90 percent of all commercially farmed tilapia
outside of Africa are Nile tilapia. Less commonly
farmed species are Blue tilapia (O. aureus),
Mozambique tilapia (O. Mossambicus) and the
Zanzibar tilapia (O. urolepis hornorum). The scientific
names of tilapia species have been revised a lot in the
last 30 years, creating some confusion. The scientific
name of the Nile tilapia has been given as Tilapia
nilotica, Sarotherodon niloticus, and currently as
Oreochromis niloticus.
5. Water Temperatures
for:
Tilapia are native to Africa, Israel and Jordan
Best growth- above 250
C
Spawning - above 200
C
Death- 10 to 120
C
Tilapia are native to the lakes and rivers of Africa, Israel and Jordan and have been present on
African dinner plates for thousands of years. Over 80 tilapia species have been identified in Africa.
Tilapia have been introduced to most tropical and temperate climate countries in the world. Tilapia
need water temperatures above 250
C to grow well, 200
C to reproduce and will die in water below 10
to 120
C. Tilapia must be placed in warm water sources or in greenhouses to survive winter water
temperatures in temperate climates.
6.
7.
8.
9.
10.
11.
12. • males: anus (anterior); genital papilla with single urogenital opening at end.
• females: anus (anterior); genital papilla with two openings,
an oviduct and a ureter.
Fins: to maintain its position, move, steer and stop
: the fins are supported by spines that are rigid and may
be quite sharp thus playing a defensive role
• paired fins
– pectoral (chest) fin with spines;
– pelvic (hip) fins located anteriorly
– help to stabilise fish and assist with steering,
stopping and hovering.
• unpaired fins
– long spiny dorsal fin
– anal fin with spines
• reduce rolling motion during swimming and help in turning movements
• primarily help fish to not roll over onto their sides
– caudal fin: main fin for propulsion to move the fish forward.
• homocercal, not deeply forked.
– Thin, forked tail fins are for continuous, fast swimming.
– Less differentiated tail fins are for less active fishes that may use
a short burst of speed to escape a predator or catch a prey.
13. Genital Papilla of Tilapia
Male papilla
Female papilla with
oviduct
anus
anus
16. Sexual Dimorphism- sexes separate
Male Female
•Two apertures on ventral side of belly
Anus and urinogenital
•Urinogenital aperture smaller
•Three apertures- anus, urinary
And genital aperture
•Bigger Urinogenital aperture
Age at first maturity -10 -17 cm length and 4-5 months
Courtship behaviour- Males show active display in their breeding territory –
called lek,
Nests are prepared by scooping out depressions at pond bottom. Mature femal
Visits the pond and there is immediate courtship and mating.
Mature fish spawn 6-12 times in a year. The number of eggs in one batch –
100- 2000.
Larger females produce more eggs per batch and eggs are larger in size.
17. Larval care in Tilapia culture
•Newly hatched larvae are delicate and reared in trays in a flow
through system (Yolk sac absorption tray)
•Rearing continues for upto 20 days after hatching
•Tray made of Al or plastic 40X 25 X 8 cm or 40 X 30 X 10 cm with
holes on lateral sides
•Fine meshed plastic or nylon net is fixed inside the tray, prevents
the escape of the hatchlings when water flows through the tray
•A 3 cm water depth is maintained in the tray
•Faster the flow rate, the lesser time it takes for yolksac abspn.
•Fry after yolksac abspn – called swim fry start feeding,
fed 4-8 times/day
18. Parental care
Tilapia niloticus is a maternal mouth brooder
Soon after fertilization the eggs are picked up by the female in its mouth
for incubation. Then the female leaves the territory or lek.
Incubation period varies from 4-10 days depending on temperature.
At 20 Deg C - - 6days
At 28 Deg C – 4 days
At 30 Deg C- only 3 days.
After hatching, larvae takes 4 to 6 days for yolk sac absorption.
When fully absorbed , the larvae leave the mouth of the mother.- swim
up fry- start feeding.
Mother continues to shelter the larvae for 1-4 days more.
Larvae takes 10-12 days to become
fully independent.
Mother does not feed during incubation but
starts feeding vigorously when the period is over.
Eggs- large yolky , size of eggs vary
according to the age of parent fish.
19. Oreochromis mossambicus (Java Tilapia)
•Widely cultured
•Monogamous maternal mouth breeder
•Sexual maturity at 2-3 months of age and 6-10 cms long.
•Breed in shallow waters 30-90 cm
•Males prepare the nest which are depressions of 35cm dia.
•Female lays the eggs and are fertliised by the male.
•75-100 eggs are taken into the mouth of the female.
•Eggs hatch out witihin 2-5 days
•larvae are retained in the mouth till the yolk sac is fully absorbed.
•Offsprings when threatened return to the mouth of female for 10-15 days.
•Female seldom eats during incubation time.
•Breeds 6-11 times a year, once in every 22-40 days.
•Breeds when temp. is 21-23 deg.C and when the temp lowers to 11-13 Deg.C
it stops breeding.
21. Eggs can be removed from females:
Incubating tilapia eggs
Yolk-sac tilapia fry
22. Tilapia can be spawned in:
1. ponds
2. cages ( hapas )
3. tanks
23. Fry can be harvested:
2. 40 days after stocking
brood fish
1. 18 days after stocking
brood fish
24. Fry can be:
1. partial harvested
2. completely harvested
25. PRODUCTION OF MONOSEX SEED OF TILAPIA
Hormonal sex reversal Hybridization
Tilapia farmers choose to raise male tilapia only since they have a
higher growth rate compared to females
26. Hormonal sex reversalHormonal sex reversal
Newly hatched larvae are fed with hormones in the feed for 3- 4 weeks
starting from 10 th day of hatching when the gonad is in
the undifferentiated stage.
17 alpha methyl testosterone – hormone used for sex reversal
17 alpha ethynyl testosterone is also used.
Feminization of genetic male done through estrogen – these functional
females when mated with genotypic males all male offsprings.
are produced.
27. Tilapia can be cultured as:
1. Mixed sexes - males
and females together
2. Mono-sex - only males
29. Advantages:
1. Large harvest weight
2. Uniform size at harvest
Disadvantages:
1. Technically difficult
Mono-sex culture
30. Mono-sex male tilapia populations can
be produced by:
1. Visual selection
2. Hybridization
3. Sex-reversal
4. Genetic manipulation
Male Populations
35. Tilapia are raised
in:Large earthen ponds
Harvested tilapia are held in net enclosures
while waiting to be loaded onto trucks for
transport to processors.
39. Tilapia are raised in:
Indoors with water reuse, mechanical aeration and oxygen injection
40. Tilapia ponds can be fertilized with organic
and inorganic fertilizers to increase yield
41. Over 2.0 million mt of farmed tilapia
were harvest world-wide in 2004.
China>Egypt>Indonesia
U. S. tilapia Production 2004: 9,000 MT
Editor's Notes
Tilapia Culture by Leonard Lovshin, Department of Fisheries and Allied Aquacultures, Auburn University, Alabama.
Tilapia with a minimum weight of 25 to 30 g can be separated by visual inspection of the genital papilla. The male genital papilla is pointed and contains only the small urogenital pore which is difficult to observe. The female papilla is rounded and contains a small opening to the urinary duct and a larger oviduct. Selection is usually based on the presence or absence of the oviduct. Males are stocked for further growth while females can be used as brood stock or discarded. Visual selection of male tilapia is costly because of the extra labor needed to separate males from females.
Males dig a bowl shaped nested in soft bottom substrates. Nests are located in shallow water. The male defends his nest territory from invasion by other males. Males and females reach sexual maturity when they are 3 to 5 months of age. Females ready to spawn enter a nest and after a short courtship, lay their eggs on the nest bottom. The male quickly fertilizes the eggs. The female picks up the fertilized eggs in her mouth for incubation. The female leaves the nest area to care for her eggs. The male is ready to spawn with another female. The female will incubate the eggs in her mouth for 5 to 6 days before they hatch. The female will continue to care for the yolk-sac fry in her mouth. Fry that are free-swimming and leave the females mouth to feed are still cared for by the female. At any sign of danger, the female signals the fry and they swim back into her mouth for protection. The female cares for the eggs and fry for 2 to 3 weeks. During this time, she does not eat. Females can spawn 4 to 6 times a year where water temperature permit. Females spawn about 1 to 2 eggs per gram body weight. A 400 g female can spawn between 400 to 800 eggs. Tilapia egg fecundity per spawn is low but egg and fry survival are high because of female care. Fry are 8 to 10 mm long at hatch.
Some farmers prefer to remove the eggs from the mouths of females and incubate the eggs artificially. Farmers collecting eggs must be able to easily collect the females. Brood fish are stocked into hapas to facilitate female collection. Females are collected 5 days after placing them with the males to assure that eggs and not fry are collected. The eggs are transferred to a hatchery and placed in incubators with clean flowing water. The recently hatched yolk-sac fry are removed from the incubators and place in containers with clean flowing water to allow them to absorb their yolk sacs and become stronger. When the fry are free swimming and looking for food, they can be transferred to ponds with zooplankton or placed in larger containers where they are fed a nutritious powdered feed.
Tilapia spawn naturally in a variety of containers. Most cultured tilapia are spawned in small earthen ponds. Fry and small fingerlings are periodically harvested from the ponds with a seine net. Normal stocking density in earthen ponds is 1 brooder per m2 and a ratio of 1 male for every 2 to 3 females. Tilapia can also be spawned in small mesh cages ( hapas ) or in concrete or fiberglass tanks. Tilapia do not need a soft substrate to spawn. Males, though unable to dig a nest, still defend a territory and females lay their eggs on the hard bottom. Stocking density in cages or tanks is 3 to 5 brooders per m2 and a ratio of 1 male to 1 female.
Removing fry from spawning ponds 18 days after stocking brood fish results in higher numbers of fry per female but survival of fragile fry is reduced due to handling stress. Larger fry ( 1 g ) can be captured 40 days after stocking brood fish to increase survival. However, cannibalism of large fry on small fry lowers the number of fry harvested per female. Most tilapia farmers prefer to harvest fry 18 days after stocking brood fish because the number of offspring per female available for stocking nursery ponds is higher than waiting 40 days after stocking brood fish to harvest fry.
Small fry ( 0.05 g ) can be harvested 18 days after stocking brood fish by partial seine harvest of full ponds or by pond draining to remove all fry. Pond margins are seined with a 1.6-mm mesh net daily to remove fry. Daily seining is continued for 1 month after which the pond is drained and a new spawning cycle started. Complete fry harvest is accomplished by draining the pond water to a sump or catch basin. Brood fish are removed from the catch basin before fry removal. Brood fish are lifted from the catch basin with a large mesh net that was placed in the catch basin before the pond was filled with water and the spawning cycle started. After brood fish are removed, fry are captured with 1.6-mm mesh nets or dip-nets. Spawning ponds must be poisoned or completely dried to eliminate any fry that remain in the pond after harvest before the next spawning cycle is started. Often, male and female brooders are held separately for a 7 to 10 day rest period before restocking in the spawning pond.
Tilapia reach sexual maturity at 3 to 5 months of age and will reproduce in grow-out ponds. To reduce the possibility of unwanted reproduction and stunting in grow-out ponds, male tilapia are cultured alone. Male tilapia are preferred because they grow faster than the females.
Mixed-sex tilapia are easy to raise and permit low income, inexperienced farmers an opportunity to farm fish. Mixed-sex tilapia fingerlings can be grown to 100 to 150 g in 4 to 6 months before offspring from unwanted reproduction becomes a problem. Ponds that are not harvested in 4 to 6 months quickly fill with offspring that compete for food with the stocked tilapia. Tilapia growth slows and many small tilapia are harvested. However, mixed-sex tilapia yields per pond area can be very high and is a good method to culture tilapia if a small fish is acceptable by consumers.
Often, a small tilapia is unacceptable to consumers and a larger fish is required. Stocking mostly male fish will result in a larger weight and more uniform size at harvest because few tilapia offspring are present in the grow-out pond. However, producing mostly male tilapia fingerlings and growing them to harvest requires understanding monosex tilapia culture techniques. Inexperienced tilapia farmers often have problems producing male tilapia fingerlings for stocking into their culture ponds.
Male tilapia populations can be produced by visual selection, hybridization, sex-reversal and genetic manipulation.
Two species of tilapia can be crossed to yield all-male offspring. The male Hornorum tilapia can be hybridized with the female Nile tilapia and offspring are all-male. However, the hybrid is fertile and can backcross with female Nile and Hornorum tilapia. Only genetically pure Hornorum and Nile tilapia will result in 100% male offspring. Maintaining pure lines of Nile and Hornorum tilapia over a long period of time is difficult. Additionally, hybrid fry yield per female is low compared with fry yield from pure species spawns.
During the last 10 to 15 years, the most popular way to produce all-male populations is with hormone sex reversal of tilapia fry. Recently hatched tilapia fry obtained by harvest from spawning containers 18 days after brood fish are stocked or hatched from eggs taken from females are fed a powdered diet containing a male steroid for 20 to 28 days. Fry that would have been females if fed a steroid-free diet, will be functional males at the end of the hormone treatment. While all-male populations are hard to produce with sex reversal treatment, 95 to 98 % males are commonly produced.
Female Nile tilapia are homozygous ( XX ) and male Nile tilapia are heterozygous ( XY ) for sex. A pairing of genetically normal male and female Nile tilapia will result in 50 % male and 50% female offspring. Normal fry that are fed estrogen for 28 days will result in phenotypic all-female fry. However, 50% of these feminized fry are genetic females ( XX ) and 50% are genetic males ( XY ). These females are individually paired with normal males. A genetic female ( XX ) paired with a genetic male ( XY ) will have offspring that are 50% male and 50% female. Females from this crossing are discarded. When a genetically male female ( XY ) is crossed with a genetic male ( XY ) the offspring will be 25% female ( XX ) and 75% males ( 50% XY and 25 % YY ). Again, individual pairings with a genetic female ( XX ) are required to determine which male is YY. The YY males or “ supermales “ will sire 100% male offspring ( XY ) when paired with genetic ( XX ) females.
Tilapia have been raised in small hand dug, family ponds for years. Commonly, mixed-sex tilapia fingerlings are stocked and fed with household food scraps and on-farm by-products. Pond waters can be fertilized with animal manures. The Guatemalan farmer in this photo uses the manure from the chickens placed in the enclosure over his pond to fertilize the pond water. The fish harvest is consumed by his family or sold to neighbors.
Farmers that produce tilapia to sell in local or distant markets often stock large earthen ponds with male tilapia. Tilapia are stocked at 1 to 3/m3 in earthen ponds. When the tilapia reach a large size and are ready for harvest, they are removed from the pond with a seine net. Harvesting tilapia with a seine from a large pond is difficult work as the fish is adapt at jumping over or swimming under the seine.
Tilapia can be grown at 100 to 300/m3 in floating cages located on lakes and reservoirs. Water is freely exchanged between the cage and the water body holding the cage to remove fish wastes from the cage. Tilapia are easily cared for and harvested from a cage but must be protected against theft. Mixed-sex tilapia can be grown in cages enclosed with large-mesh net material because females are unable to reproduce and the cage does not fill up with offspring. Eggs drop through the cage mesh before the males can fertilize the eggs and females can collect them in their mouths. Most farmers growing tilapia in cages prefer to stock male tilapia.
Tilapia can be cultured at 50 to 100/m3 in small, circular tanks with partial water exchange and mechanical aeration. One tank volume or less may be exchanged per day. Tanks are constructed with a drain located in the center of the tank. A circular water current generated by mechanical aerators carries feces and other settleable wastes to the drain for easy removal from the tank. Tilapia are easily harvested from small tanks and high yields are possible with small amounts of water exchange.
Raceways have a constant water exchange which allows the highest tilapia stocking rates and yields per area of culture unit. Tilapia can be stocked 300 to 500/m3. Raceways can be circular or rectangular in shape. Water volume may be exchanged 1 to 5 times per hour. The flowing water sweeps fish feces from the culture unit. Notice that the water falls from one culture unit to the next by gravity. As the water passes from the higher culture unit to a lower one, the water is reoxygenated and can be reused 2 or 3 times without reduction in fish yield. However, a large quantity of water is required and supply by gravity is more economical than pumping.
Tilapia are commonly raised in culture units located indoors in regions with temperate climates to permit year round growth. Little freshwater is added to the culture unit to conserve water temperature. Suspended and dissolved fish wastes are removed from the water with mechanical and biological filtration to allow reuse of the water. Oxygen concentrations are maintained with mechanical aeration and often, injection of pure oxygen. Tanks are stocked with 10 to 50 tilapia/m3. Most tilapia produced in the United States are cultured in enclosed, water reuse systems because of the temperate climate.
Fertilizing pond waters with organic and inorganic fertilizers increases tilapia yields by promoting the growth of phytoplankton and zooplankton consumed by the tilapia. Tilapia ponds are commonly located next to livestock enclosures so that manures are easily washed into the ponds during cleaning. Associating tilapia with ducks is a common practice in Asia.
Tilapia are farmed in many countries. China is the world leader of farmed tilapia harvesting over 900,000 mt in 2004. The Philippines and Thailand are also major producers of tilapia in Asia. Brazil, Colombia, Ecuador, Honduras and Costa Rica harvest most of the tilapia farmed in the Americas. U. S. tilapia farmers harvested 9,200 mt in 2004.
