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An Educational tour to Trout Fish farm Dhamwari(12.03.2016)


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Compiled by:
Young Biologists Association
(Deptt. of Zoology & Botany)
Govt. P.G. College, Seema

 

 

Contents

Sr.No.         Title                                                                             Page

  • Introduction                                                                                  1
  •  Objectives                                                                                    1 
  • The farm                                                                                       1
  • Activity conducted and the lesson learned                                   4
  • Observations                                                                                 5
  • Learning outcome of visit / Conclusion                                       6
  • References                                                                                    7                         

             

 

 

Abstract
In an effort to provide exposure and practical knowledge about the rearing of Trout to the students, the Young Biologists Association organized an educational tour to visit Trout fish farm Dhamwari. Fishery officer of the farm, Mr. Ram Singh showed and demonstrated the complete life cycle of the of the fish showing different developmental  stages such as  Eggs, Two eyed ova, Elvin stage, Fry stage and the Adults. He explained in detail the rearing process and nutritional value of the Trout. He also motivated students to adopt Trout farming as a self employment opportunity and provided necessary information regarding the material required, space, water supply, temperature requirement and all other requirements to start a rearing of the Trout. The students were quite enthusiastic and satisfied after acquiring so much knowledge about Trout Fish.
1. Introduction:
Trout fish Farm Dhamwari was established in the year 2005. It is located on the right bank of river Pabbar, about 35 km from the Rohru town. The water to the farm is drawn from the khanyara khad at the rate of 150 Lt/sec through GI Pipe. Trout fish cultivated at the farm is Rainbow Trout (Oncorhynchus mykiss). It is an exotic species native to cold water tributaries of North America. In an effort to provide exposure and practical knowledge about the rearing of Trout to the students, the Young Biologists Association organized an educational tour in 12.03.2016 to visit this farm. Nearly 50 students of the Association visited the farm with curiosity and enthusiasm. Mr.  Rajesh Azad, Dr. Ravi Kiran Sharma (Deptt. of Zoology), Dr. Umesh Narta and Ms. Ritika Chauhan (Deptt. of Botany) accompanied and supervised them on this visit.
2. Objectives:

  • To study the rearing process and nutritional aspects of trout fish.
  • To study the various parameters such as space, dimensions, water flow, temperature and oxygen content etc. required to start cultivation of Trout.
  • To   give exposure to the students   to motivate them to opt trout farming as career option.

3. The Farm:

  • Infrastructure available:
  • Raceways:                  11 (3) ( 15x2.17x1.5m)

                                                (8) (15x2.4x5m)

  • Hatchery Building:    1 ( containing 4 start feed Tanks , 2 nursery tanks and 6 hatching troughs with 24 trays.
  • Capacity :
  • Farm:     The farm has production capacity of 5 Tonnes.
  • Hatchery:    Installed capacity of  100000 Ova and 50000 Fingerlings
  • Cultivation of Trout:

Trout fish cultivated at the farm is Rainbow trout   (Oncorhynchus mykiss).It require temperature range of 4-18 0C. Water should be fresh and running (1 L/min) with dissolved oxygen content (over 1mg/L). Trout culture methods are essentially based on artificial spawning for obtaining the seed. Thus the methods include maintenance of brood stock of ripe males and females, their stripping for release of eggs, subsequent fertilization, and incubation of eggs until hatching, rearing of Alevins, raising of fingerlings to marketable size and harvesting. The various steps in cultivation are as follows:

  • Selection of the brood: The broods   should be having high fecundity, large egg size, higher hatching rate, faster growth, greater resistance to disease, greater tolerance to water temperature.
  • Stripping:  Stripping is done by hand in months of Nov-Feb. .First the eggs are obtained from the female and then milt from the male are collected.
  • Incubation: This is done in water at 10 0C with dissolved concentration of oxygen at 7 ppm with flowing rate of 14-24 L/minute. Hatching may occur in 30-45 days.
  • Rearing of Alevins: Rearing of Alevins is done in troughs until the yolk sac is completely absorbed. Conditions are similar as for incubation. However, once free swimming fry stages are there flow of water not les than3600 L/minute is necessary. The temperature should be between 10-18 0C and pH should be in the range of 7.0-8.5 and it should have dissolved oxygen concentration at 5 ppm.
  • Raising of Fingerlings:  Raising of fingerlings is done in raceways of the dimensions mentioned above. For 1000 fingerling , a flow of 1L/min per month(age) is used.  Feeding of the fingerlings is done regularly with feeding pellets. Trout  pellets consists of mixture of wheat, fish meal, yeast and Whey etc. Such pellets contain 30% proteins ,30% carbohydrates and 10% fats and other ingredients  like fibre, vitamins and  antibiotics etc.
  • Grading:  The stock should have uniform size so that harvest of uniform size is obtained for marketing. Box graders are used for this purpose.
  • Harvesting: Harvesting is carried out either by draining or by seining.

Diseases of the fish: Trout fish is mainly affected by the fungal diseases, bacterial gill diseases, fin rot etc. To prevent fungal diseases fish are given bath of KMnO4, Malachite green and Rock salt.

 

  • Major species reared at Dhamwari Farm:
  • Rainbow Trout (Oncorhynchus mykiss) or Salmo gairdeneri gairdeneri ( Old Nomenclature)

Classification:
Kingdom: Animalia
Phylum:   Chordata
Class:       Actinopterigii
Order:     Salmoniformes
Family:   Salmonidae
Genus:    Oncorhychus
Species:   mykiss
Habits& habitat
The Rainbow Trout (Oncorhynchus mykiss) is basically exotic species native to cold water tributaries of North America. This species ranks as most important of all trout as this  fish is easiest for culture, exhibits greater adaptability to temperature (4-18 0C), water quality, high stocking density, artificial food, dissolved oxygen and so on. It has moderately good growth rate and is also more resistant to diseases.
Morphology:
Body is fusiform & and colour ranges from blue green to olive green. There are black spots on entire length of the body. Male Trout can be distinguished from the female externally as it has hooked lower jaw.

  • Brown Trout (Salmo trutta fario)

This is Europeans species of trout but is not as good as Rainbow trout for rearingas it has slow growth rate, demand  strict conditions of water quality and oxygen . It is found in local khaneri khad and in Pabbar river.

 

 

 

4.  Activity conducted and the lesson learned:
The  Fishery Officer  of the farm Mr. Ram Singh showed and demonstrated the complete life cycle of the of the fish showing different stages such as  Eggs, Two eyed ova, Elvin stage, Fry stage and  Adults as shown in pictures below. He explained the complete  rearing process of the trout, its feeding, care taking, monitoring its diseases ,precautionary measures  and finally its marketing. He acquainted the students about  nutritional  value of the trout which is  very high as it contains easily digestible primary proteins, HDL lipoproteins and Omega-3- Fatty acids  which are good for health.  He also motivated students to adopt trout farming as self employment opportunity.    (Fig. 1)
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Fig-1.  Demonstration of the life cycle and other aspects of trout fish in the trout hatchery by       Mr. Ram Singh , Fishery Officer.)

 

 

5.  Observations:

 Life Cycle

Adult male and female breed in the months of Nov-Feb. Eggs are collected by stripping method from female and male are milted later. Fertilization is external. Hatching of the eggs depends upon the temperature. If the temperature is 100C then hatching occurs in one month. If the temperature is 7-8 0C then hatching occurs in 50-52 days and if the temperature is 5-6 0C then hatching occurs in two months. Life cycle of the fish shows following stages:

Eggs:
The first stage is green eggs (zygote) which turns green after 11 days. White coloured ova are dead eggs. After 21 days eggs are transferred to different hatching tray. This is also called as second stage. The 3rd stage is one eyed ova formed after 1 month.  4th stage is two eyed ova. In one hatching tray about 3000 eggs are kept.
Alevin:  
Once hatched, the trout have a large yolk sac used as food source. This stage is called as Alevin.
Fry: 
Alevin  metamorphose in to Fry Stage which swims close to water surface. This stage require high amount of protein (40-50%). The hens egg meshed with feed is provided to them up to 8 times a day.
Fingrlings and Parr:
After early stages fish are shifted  to nursery ponds. When fry stage grows to 2-5 inches it becomes fingerling. When it develops large dark markings it then becomes a parr.These stages are formed at the end of April.
Juvenile:
in this stage trout resembles  an adult but is not yet old or large enough to spawn.

 

 

 9  10
              
 1112
                                             Alevin                                                                            Fry
              1314
                                                 Juvenile                                                                   Adult
                                           Fig.2-Different stages in the life cycle of the Rainbow Trout
6. Learning outcome of visit / Conclusion:
Trout is one of the most nutritious fish of the fresh water. It can be easily reared artificially in regions where the temperature remains cold (4-18 oC) most of the year. The commercial value of the fish is very high as it fetches as good as 400-500 Rupees /Kg. So trout fish farming can be very good opportunity for Self-employment option for the youth of the local area. The students  were quite satisfied with the visit as they acquired a lot of useful information about the trout culture, its nutritional value and commercial value. They were quite encouraged and were of the opinion that more of such activities should be conducted in future.
7. References:

  1. Srivastava, C.B.L. (2012) Trout Culture. A text book of fishery science and Indian fisheries. Kitab Mahal, p-359.
  2. www.hpagrisnet.gov.in