Considering the suitable climate conndition and abundanca of cold water, juvenile brown trout were introduced from India for the first time during late 1969 and Rainbow trout from the United Kingdom in 1971. They were distrubted in two places. Few hundred juveniles were kept in Godawari in a cemented tank and the rest of them were transported to a newely established Trisuli Trout Hatchery. Rainbow trout (Oncorhynchus mykiss) is one of the most suitable fish to cultivate in cold waters. It can survive in cold waters having a water temperature range from 0 to 25 degree celsius, but performs relatively well for growth in 16-180 C. The water temperature range from 9 to 140 C is considered suitable for maintaining spawners for breeding and incubation. Trout can breed after attaining two years. In general, a 3-4 years old single female can laid up to 3,000-3500 eggs/kg however, breeding performance and quality egg depends on the quality of water, feed and other management practices. The brood fish should be fed at least 35% protein content diet at the rate of 2-3% of body weight once or twice daily. Two years old adult rainbow trout are bred artificially once in a year during December to March and the same group of brood can be used for coming years. The older brood generally lays higher number of eggs/kg body weight. These broods also produce larger eggs. The smaller eggs might have low hatchability contrarily larger size of eggs produce higher alevin. The eggs are stripped from females and the stripped eggs are fertilized with the milt obtained from males . Normally, one male can supply enough milt for the eggs of two females. The fertilized eggs are incubated in incubation trays in Atkins incubators, where clean and cold water had been supplied @ 3-7 L/sec. The water used for incubation should contain the concentration of dissolved oxygen (DO) >7 mg/L. The eggs used for incubation hatch out within 20-30 days interval depending on water temperature.

1. Breeding of Rainbow Trout in Nepal
Presented By:
Pabitra Pandey
B.Sc. Fisheries
Agriculture and Forestry University
Rampur, Chitwan, Nepal
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2. Lists of contents
• Background
• Rainbow Trout
• Breeding of Rainbow Trout
• Male and Female Identification
• Breeding Process
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3. Background
• Aquaculture is one of the fastest growing agriculture subsectors in Nepal
• Having landlocked in nature, Nepal depends only on inland aquaculture
with finfish farming
• Climate condition favors both warm water and cold water species
• Common species under cultivation; indigenous and exotic carps, pangas
catfish and Rainbow trout
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4. Rainbow Trout
• Scientific name: Oncorhynchus mykiss
• Order: Salmoniformes
• Family: Salmonidae
• Carnivorous species requires high protein feed and well oxygenated
water
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5. Rainbow Trout
• It can survive in cold water having a water temperature ranging from 0 to
25 °C
It grows at the water temperature range of 10-20°C
Best temperature for growth ranges of 16-18°C
For breeding temperature ranges of 9-13°C
• In Nepal, it reaches 200-300 g within 14-months from the free-swimming
larval stage depending on:
 Quality of the feed
 Adequate supply of water
 Suitable temperature and dissolved oxygen concentration
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6. Breeding of Rainbow Trout
• Rainbow trout was bred for the first time in Nepal in 1990
Culture was initiated experimentally in 1993
• Breeding Started from 1st week of Kartik to 1st week of Falgun
• Age for breeding : 1+ (above 23 month)
• Breeding time : Once times a year
 Same group of brood can be used for upcoming years
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7. Breeding of Rainbow Trout
• A 3-4 years old single female can laid up to 3000-3500 egg/kg
• Breeding performance and quality egg depends on:
Quality of water, feed and other management practices
• Brood fish should be fed at least 35% protein content in diet at rate of
2-3% of body weight once or twice daily
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8. Breeding of Rainbow Trout
• The older brood
Generally lays higher number of eggs/kg body weight
Can produce larger eggs
larger sized of egg produce higher alvein
• The smaller eggs
• Might have low hatchability
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9. Male and Female Identification
Male
• Male have more elongated
snout, lower jaw have distinct
hook
• Normal abdomen
• Concave Vent
• On slight pressure above the
vent on the abdomen, milky
white fluids (milt) runs through
the vent
Female
• Female have short rounded nose
or upper jaw
• Bulging out on both sides or
puffy, soft and palatable
• Convex vent, projecting like a
small papilla, pinkish in color
• On slight pressure, eggs come
out from the vent
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10. Breeding Process
• Eggs are stripped from females
• Milt were mixed into the eggs
• One male milt used to fertilized three females stripped egg
• But for conformation double milting was normally practices
• Eggs and milt mixed properly with feather
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11. Breeding Process
• After mixing, Dip egg in 0.9% of salt solution for 2 minute
• Clean with fresh water to remove dead egg, blood etc.
• Clean cold water increased the egg sized about 20%
• Fertilized eggs are incubated in incubation tray in Atkins incubators
Where clean and cold water had been supplied i.e. 3-7L/sec
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12. Breeding Process
• Water used for incubation should contain the concentration of dissolved
oxygen (DO) greater than 8 mg/L
• The eggs used for incubation hatch out depending on water temperature
• Atkin should be covered with black plastic, prevent rays of light reached to
the eggs
Eggs are light sensitive
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13. Breeding Process
• After 21 days of incubation, eye developed called eyed egg stage
Ready for transportation
• Dead eggs or fungus attracted egg were removed
• Transfer to the cage in nursing tank
• Newly hatched sac fry often called ”Alvein” weight about 0.08 g each and take
about 2 weeks to attain swimming stage.
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14. Breeding Process
• Sac fry attains swimming stage after absorption of the yolk sac
• At the beginning the alvein with a large yolk sac (reserved food) can
not swim well
• Alvein are fed with starter feed, which contains 35-40% crude protein
• Feeding carried at the rate of 15-20% of total biomass of fry
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15. Breeding Process
• Feeding is generally performed at 2-hour intervals in day time till
attaining 3 g size, which take about 10 weeks
• After 3 g sizes fingerlings are fed 8-10% body weight of fish at 2 hours
interval till about 5 g sizes
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Figure: Brood Fish Selection

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Figure: Stripping of Egg and Milt

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Eggs Eggs with Milt
Fertilized egg in salt solution

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Fertilized egg clean with cold
water
Eyed eggs

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Picking of dead Eggs
Transfer of eyed eggs into cage
Fry with yolk sac

21. THNAK YOU !!
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