Breeding of catfishes

Breeding of catfishes

10.1. Breeding of Asian catfish (Clarias batrachus )
Clarias batrachus is cultured mainly in Thailand, Bangladesh and India.
An important foodfish, commands high price (up to Rs. 200/-per kg) depending on local preference
The catfishes of commercial/aquacultural importance are 

• Asian catfish, Clarias batrachus,
• African catfish, Clarias gariepinus,
• European catfish, Silurus glanis, 
• American catfish, Ictalurus spp.,
• Thai catfish, Pangasius hypothalamus, etc.

Distribution and importance of C. batrachus

• C. batrachus belongs to the family Claridae and Order Cypriniformes.
• Also known as `Magur or walking catfish’, it is distributed in India, Bangladesh, Thailand, etc.
• Found in derelict water bodies like swamps, marshes and ponds and tanks.
• Can be cultured in oxygen-poor waters, as it is an air-breathing fish
• An important food fish in North-Eastern States such as Assam, West Bengal, Orissa, Bihar, etc.
• But carnivorous and cannibalistic when food is scarce.
• Grows to 200 g in 6-8 months

Identifying characters

• Elongated body.
• Head moderately depressed.
• Mouth terminal.
• Barbels four pairs, the maxillary pair extends considerably beyond base of pectoral fin while the nasal barbells extend to gill openings.
• Dorsal fin inserted slightly anterior to tip of pectoral fins.
• Pectoral spine strong, finely serrated on both sides.
• Adults are dingy-greenish or brownish superiorly, becoming lighter beneath; the vertical fins usually with reddish margins.

Food and feeding

• Adults are carnivorous and cannibalistic when food is scarce.
• Juveniles are omnivorous.
• Fry feed on zooplankton, while fingerlings prefer small crustaceans, worms, mollusks, etc.

10.1.1. Brood-stock development

• Brood fish is maintained in cement cisterns with a layer of soil and running water.
• Stocking density is 8,000 nos. /ha
• Fed with a mixture of ground trash fish and rice bran (9:1)
• Fish meal, wheat flour and soya cake can also be used in the diet
• Feeding rate 10% b.w. daily.

10.1.2. Selection of broodfish for injection

• Proper selection of broodfish is important for successful results.
• Attains maturity after one year (150 g and above)
• Sex of brood fish is identified based on secondary sexual characteristics which are more pronounced during breeding season.
• Females are slightly larger and have round and blunt genital papilla
• Males are slightly smaller and have elongated and pointed genital papilla
• Breeds naturally during April-July in paddy fields. 

10.1.3. Induced spawning

• Various hormones have been found to induce spawning in this species.
• Selection of hormone and proper dosage are essential for successful breeding.
• Intramuscular injection is common.

The hormones and their doses are as follows

Hormone	Dosage
	Female	Male
Pituitary	20-30 mg/kg	1/3 dose
HCG	4,000 IU/kg	1/3 dose
Ovaprim	0.5 – 0.6 ml/kg	0.25 ml
Ovatide	0.6 – 0.7 ml/kg	0.30 ml
WOVA-FH	0.6 – 0.9 ml/kg	0.2-0.4 ml

10.1.4. Stripping and fertilization

• At 14-16 hours after the injection, the male sacrificed, the testes dissected out and squashed in 0.9% NaCl solution.
• This sperm suspension can remain dormant (fertile) up to 24 hours.
• After the sperm suspension is ready, the eggs are stripped onto a clean basin/tray and are immediately fertilized with the sperms (suspension)
• The developing eggs are small, adhesive and are incubated in plastid basins (12 cm diameter x 6 cm high) with running water
• Fecundity : 5,000 – 50,000 eggs/female
• Fertilization rate : 80 – 90%
• Unfertilized eggs get washed away by overflowing water
• Hatching period : 24-26 hours at 29-31⁰ C.
• Eggs are hatched in 500 l capacity plastic/FRP tanks .
• Larvae depend on yolk for 3-4 days.

10.1.5. Larval rearing

• The hatchlings (5-5.5 mm) reared on Artemia nauplii or sieved zooplankton for 4-7 days, after which they are fed with egg yolk/white suspension for 8-15 days.
• The aerial respiration starts after 10 or 11 days.
• Water exchange 50-60% daily; aged water preferred
• Fingerlings are reared in out-door tanks where they are fed with ground trash fish and rice bran (1:1); stocking density : 200 nos./m²
• Prawn or molluscan meat can also be used
• Attain 6-8 cm in 30 days and are ready for transfer to grow-out pond.

Breeding of Pangasius spp.
• An exotic species now widely farmed in India
• About one lakh tons of fish produced annually
• Fish seed supply is from Bangla Desh and West Bengal 
• Pangasius hypothalamus is one of the major fish species in the Mekong River fishery, one of the largest and most important inland fisheries in the world.

•• Originally known as Pangasius sutchii or Pangasius hypophthalmus, this riverine freshwater species is limited to the Mekong River basin in Cambodia, Lao People's Democratic Republic, Thailand and Viet Nam, together with the Ayeyawady basin of Myanmar, within a range of 19 °N to 8 °N. The species has a variety of common English names including Sutchi catfish, iridescent shark-catfish, and striped catfish

•• Like all Pangasiid species, P. hypophthalmus is a highly migratory riverine fish species that makes long-distance migrations over several hundred kilometres (potamodromous) between upstream refuge and spawning habitats and downstream feeding and nursery habitats.

•
• P. hypophthalmus is omnivorous, feeding on algae, higher plants, zooplankton, and insects, while larger specimens also take fruit, crustaceans and fish.

 

•• Mature fish can reach a maximum standard total length of 130 cm and up to 44 kg in weight

•• Females take at least three years to reach sexual maturity in captivity (over 3 kg in weight), while males often mature in their second year, probably taking about the same time in the wild.

•• A female (10 kg) can spawn over one million eggs.

•• Wild broodstock typically spawn twice annually but in cages in Viet Nam have been recorded asspawning a second time 6 to 17 weeks after the first spawning.
Induced breeding
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• P. hypophthalmus can be induced to spawn using HCG or HCG and pituitary glandextract.

•• Females receive 2-4 hormone injections, while males are injected only once at the timeof resolving dose to the female.

•• Broodstock are spawned in single pairs or in larger numbers and are usually drystripped.

•• The eggs are incubated in conical jars made either of stainless steel or glass, with up-welling water flow to keep the eggs in suspension.

•• The eggs hatch within 22-24 hours.

•• Yolk-sac absorption takes takes 24 hours.

•• The larvae are transferred from the hatchery just prior to the complete yolk-sacabsorption
Production cycle - illustration

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Nursery rearing

• Nursery rearing is done in 2 separate stages.

•• Earthen ponds (1 000-5 000 m2), are prepared by drying, liming (1 t/ha), manuring and inoculating withMoina.

•• In the first nursing phase larvae are stocked at 400-500/m2 just prior to yolk sac absorption, so that natural feeds are available and the larvae have enough space to avoid cannibalism.

•• Boiled egg yolk and soybean meal mixed into an emulsion is fed 5 -6 times a day for the first 2 weeks. Thereafter commercial pellets are fed.

•• After 4 weeks, the nursery ponds are partially (about 1/3 depth) drained, harvested and stocked at 150-200/m2 in another pre-prepared pond without Moina.

•• Typical larvae to fry survival rate during the first nursing stage is 40-50%.

•In the second nursing stage, from fry to 14-20 g fingerlings, survival over the 2 month nursing period are typically 60-70%.

Common crops breeding link click here 

https://fishgate2001.blogspot.com/2022/08/breeding-of-common-carp.html