TILAPIA CULTUREby

Leonard LovshinDepartment of Fisheries and Allied Aquacultures

Auburn University, AL 36849 U.S.A.

TILAPIA HISTORY AND ORIGIN

The Nile tilapia (O. niloticus) wasone of the first fish species cultured.Illustrations from Egyptian tombssuggest that Nile tilapia were culturedmore than 3,000 years ago.Tilapia have been called SaintPeters fish in reference to biblicalpassages about the fish fed to themultitudes. The Nile tilapia is stillthe most widely cultured species oftilapia in Africa.

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.

Water Temperatures for:

Tilapia are native to Africa, Israel and Jordan

Best growth- above 250C

Spawning - above 200C

Death- 10 to 120C

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 250C to grow well, 200C to reproduce and will die in water below 10 to 120C. Tilapia must be placed in warm water sources or in greenhouses to survive winter water temperatures in temperate climates.

• 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.

Genital Papilla of Tilapia

Male papilla

Female papilla withoviduct

anus

anus

Development of Tilapia

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 femaleVisits 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.

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

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 - - 6daysAt 28 Deg C – 4 daysAt 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.

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.

Reproduction

Males dig and defend a nest

Females incubate eggs

and defend the fry

Eggs can be removed from females:

Incubating tilapia eggs

Yolk-sac tilapia fry

Tilapia can be spawned in:

1. ponds

2. cages ( hapas )

3. tanks

Fry can be harvested:

2. 40 days after stocking brood fish

1. 18 days after stocking brood fish

Fry can be:1. partial harvested

2. completely harvested

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

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 reversal17 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.

Tilapia can be cultured as:

1. Mixed sexes - males and females together

2. Mono-sex - only males

Advantages: 1. Technically easy

Disadvantages: 1. Small harvest weight 2. Mixed sizes at harvest

Grow-out:Mixed-sex Culture

Advantages: 1. Large harvest weight 2. Uniform size at harvest

Disadvantages: 1. Technically difficult

Mono-sex culture

Mono-sex male tilapia populations can be produced by:

1. Visual selection

2. Hybridization

3. Sex-reversal

4. Genetic manipulation

Male Populations

Hybridization

Male Hornorum tilapia

Female Nile tilapia All-male hybrid tilapia

ZZ

XX

XZ

Sex Reversal of Tilapia Fry

Genetic Manipulation

1) XXF + XYM

estrogen

XXF + XY”F”

2) XY”F” x XYM

XXF + 2 XYM + YYM

3) XXF x YYM

100% XYM

Tilapia are raised in:

Small earthen ponds

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.

Tilapia are raised in:Floating cages

Tilapia are raised in:Circular tanks with partial water exchange and mechanical aeration

Tilapia are raised in:Raceways with constant water exchange

Tilapia are raised in:Indoors with water reuse, mechanical aeration and oxygen injection

Tilapia ponds can be fertilized with organic and inorganic fertilizers to increase yield

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