Fishery

FLD  

• Culture of Asian catfish in carp culture ponds

OFT

• Increasing profitability from carp polyculture ponds (0.065 ha or 10 katha) by diversifying fish culture through the introduction of Pengba-Osteobrama belangeri

• Increasing profitability from carp polyculture ponds (0.0325 ha or 5 katha) by diversifying fish culture through the introduction of Pearl spot – Etroplus suratensis 

Topic of Training

• Diversified freshwater fish and prawn farming
• Integrated fish farming
• Breeding & culture of indigenous fish
• Hazards in fish and prawn farming and their remedies
• Induced breeding of carps
• Ornamental fish breeding and culture
• Methods of pond preparation for scientific fish culture
• Improved method of carp fry and fingerling production for doubling farmers income
• Fish rearing and management

Livelihood generation by establishment of catfish hatchery

Indigenous catfish – magur & singhi are high value fish and are sought after by the fish loving people of Bengal. The demand of these fish is high and their supply in the market is low. Hence, seed production of indigenous catfish may be an excellent option for earning livelihood.

Requirements:  

To start with, about 10-15 glass trays of 3ꞌ x 3ꞌ x 8ꞌꞌdimension, 10-15 thermocol sheets to keep the trays, a can of brine shrimp, fish breeding hormone, insulin injection syringe, normal saline, small bent scissors, fine forceps, a bowl to hold eggs, a small bowl to hold sperm, dropper, brood fish, a fertilization frame, air pump etc. are needed which may cost around Rs.25,000/-

The technology:

a)     During the breeding season of April-September, male and female fish are collected, preferably from well managed brood fish pond.

b)     The female fish is injected with fish breeding hormone @ 2ml/kg body weight.

c)     14-16 hrs. later, eggs from the female fish are collected in a bowl after which the male fish is cut open to collect the testis.

d)     The testis is cut into pieces & squeezed with a piece of fine meshed nylon net to obtain the sperm which is collected in a small bowl containing 0.9% normal saline.  

e)     This is then mixed with the eggs for fertilization & the fertilized eggs are washed with clean water and spread over a net frame immersed in water in a glass tray.

f)      After 24 hrs., the eggs hatch and within 3 days the hatchlings transform into spawn.

g)     Spawns are fed with freshly hatched brine shrimp nauplii twice a day for 7-8 days.

h)    Thereafter, the growing spawns are fed with Tubifex worms for 10-15 days followed by feeding with pelleted feed for 2-7 days.

i)       Within 25-30 days, fry of 1.5-2.0 inch are ready for marketing.

j)       About 1000 fry may be obtained from each tray.

Economics:

From 15 trays, 15,000 fry may be produced, the selling price of which is Rs. 3/- piece. Hence, Rs. 45,000/- may be earned from a single operation. Therefore, from 6 such operations, in the 6 months of breeding season, Rs. 2,70,000/- is expected to be earned. Increasing the number of trays will increase the profit margin to a great extent.

Livelihood generation by establishment of carp hatchery

Since the days of the success of Induced Breeding in carps, the demand for carp seeds viz. spawn, fry and fingerlings has been ever increasing. The popularity of carps like catla, rohu, bata, calbasu, etc. in the bengali cuisine will always keep this trend going. Hence, establishment of a carp hatchery for seed production may be a lucrative avenue for income generation.

Requirements:

A low cost carp hatchery consisting of one overhead tank, one breeding pool, one hatching pool and one spawn collection chamber with inter connected pipelines- all constructed  on a single concrete platform of just 40ꞌ x 20ꞌ dimension is all that is required for producing carp spawns. The entire infrastructure may be erected by investing about Rs. 3.0 lakhs. Besides, fish breeding hormone, injection syringe and brood fish are the main requisites.

The technology:

Breeding of carps in controlled environment involves selection of 2-5 years old male and female brooders and injecting them with specific dose of fish breeding hormones and releasing them in circular breeding pools with shallow depths, arrangements of water flow with inlet and outlet facilities and providing artificial rain in the form of water sprinkling. This is done to simulate natural conditions for breeding of carps which although attains maturity in ordinary ponds, cannot spawn due to the absence of conditions required for their breeding. Within 4-6 hrs of injecting the brooders spawning takes place and the female fish lays eggs which are instantaneously fertilized by the sperms from the male fish through a process called coiling. All the eggs pass through the outlet of the breeding pool into the hatching pool through the overflowing water.

Hatching of eggs takes place in the hatching pool after 12-15 hrs and after yet another 48-52 hrs, the hatchlings transform into spawns, i.e. the first form of carp seeds and the final product from the hatchery. These spawns are led through the outlet of the hatching pool into a cloth enclosure or ‘hapa’ fixed in the spawn collection chamber. The sieved spawns are then collected and measured out with the help of a small bowl or ‘bati’.

A standard ‘bati’ of 160 ml volume may hold about 80,000 carp spawn and may cost between Rs.400.00 to Rs. 800.00 depending upon the type of fish and time of the season. The spawn are sold to buyers who in turn grow them into carp fry or the second type of carp seeds in well prepared nurseries. Buyers of carp fry grow them into fingerlings or the third type of carp seeds. A farmer who grows tablefish, essentially culture these fingerlings over a period of 8-11 months.

So, a carp hatchery owner can earn handsomely from cultivation of all the stages of fish, besides selling these seeds, provided he owns sufficient number of ponds.

Tips for good fish culture practices

• Prepare pond meticulously before initiating fish culture every year
• Get rid of all pre-existing fish and other aquatic animals before starting new culture
• Stock fish optimally - do not overstock or under stock
• Do not stock small fish with big ones or in other words, stock fish of more or less the same size and at the same time
• Apply organic manure, lime and inorganic fertilizer as per recommendations and rake the pond bottom by netting operation, at least once a month
• Apply supplementary feed on daily basis as per recommendations
• Keep the pond and its surrounding devoid of weeds
• Pond dykes should have such plants/trees that provide shade, check soil erosion but at the same time do not pollute the water with the falling leaves
• Ponds should be airy and have sufficient sunlight penetration
• Use cheap local ingredients as fish and prawn feed to minimize cost of culture
• Dyke of the pond should be strong and well-guarded to prevent escape of fish & prawn from the pond and also to prevent entry of wild fish into it
• To optimize production, increase the variety of fish in a pond by maintaining the recommended stocking density

Tips for saline water inundated freshwater fish ponds

·         If possible, dewater the ponds as far as practicable

·         If ponds are disinfected by spraying bleaching powder, it is necessary to rigorously agitate water to remove chlorine before stocking fish

·         After accumulation of fresh rain water in the saline water infested ponds, advanced fingerlings of both brackish water and fresh water species may be released after “Suitability testing” by holding fish in a net enclosure in the pond for 24-48 hrs.

·         Giant fresh water prawn & tiger shrimp may also be tried in such ponds

·         Tilapia may also be a suitable species to grow in such ponds

·         Asian catfish fingerlings may also be grown when the pond salinity reduces to a great extent after the monsoon sets in

N.B. For any queries contact with Mr. P. Chatterjee, SMS(Fishery), RAKVK, Nimpith   (Mob. 9434437058)