4.1.1. Hatchery proper

Unit 4 - Different types of fish hatcheries

4.1.1. Hatchery proper

  • The evolution of fish (carp) hatchery systems in India was reported by Dwivedi and Zaidi (1983).
  • Several types of fish hatchery devices are in vogue in India.
  • These range from the simplest hatching pits to the most modern.

1. Hatching pits

  • The earliest device of hatching carp eggs, used in bundh-type breeding system of Bengal, comprised pits.
  • The dimensions of the pits vary according to the requirement, but pits of 3’x 2’x 1’ are dug in multiple rows and their inner walls are plastered with mud.
  • About 30,000-40,000 eggs can be kept for hatching in each pit.

2. Chittagong type hatchery pits

  • These are similar to hatching pits except that they are each provided with a double-walled (inner mosquito netting material and outer muslin cloth) cloth linings.
  • The outer cloth is kept a few inches above the earthen bottom of the pits.

3. Earthen pot hatchery

  • This is one of the earliest types of hatchery used in association with bundh-type breeding system.
  • It comprised earthen pots arranged at different levels one draining into the other kept at a lower level.
  • This provides a flowing current of water, cooled by surface evaporation of the porous earthen pots in which the carp eggs are hatched.

4. Double-walled hatching hapa

  • The double-walled hatching hapa is one of the commonest devices to serve as an outdoor hatchery.
  • Installable in a pond or in the margin of a river, up to 1,00,000 eggs can be hatched in the inner mosquito net wall of the hapa of the size 1.75m x 0.90m x 0.75m.
  • The newly hatched hatchlings wriggle out through the round meshes of the inner wall and collect themselves in the outer whole cloth enclosure
  • Larval survival is much higher when the hatching hapa is installed in a gently or fast flowing canal or a river because of superior exchange of water.

5. Floating hapa

  • Similar in principle to the double walled hatching hapa, a floating hapa is mounted on a wooden frame to which it is securely tied such that the whole unit drifts in water.
  • The floating hapa has the advantage that it can be used on rocky substrates, often found in reservoirs and can be towed to deeper water to obtain better exchange of water.
6. Tub hatchery
  • First introduced in the Madhya Prudish State.
  • This hatchery furnishes running water to hatch eggs in galvanized iron units with adjusted levels such that water flows by gravity through interconnecting siphons.
  • Each tub (2.5’ x 2.5’x 1.5’) is fitted with double walled hapas and the eggs are constantly bathed in a gently flowing water current.

7. Cemented cistern hatchery

  • Used at Nowgong dry bundh in Madhya Pradesh and is situated generally below the dam sites
  • Each cement cistern (tank) commonly measures 2.4 x 1.6 x 0.45m.
  • It has its own inlet, situated at different levels at the opposite ends of the cistern.
  • They are often arranged in rows wherein water flows by gravity and each cistern can hatch about 3,00,000 eggs at a time.

8. Glass jar hatchery

  • The credit of developing India’s first transparent hatching device in which the developing eggs can be watched at eye level goes to Bhowmick.
  • In this system, the hatching are automatically transferred to storage hapa/spawnery, within the hatchery building itself.
  • The main components of Bhowmick’s glass jar hatchery are : an overhead tank, fish breeding tank, incubation/hatching jars and a spawnery to hold the newly hatched spawn.
  • The capacity of the overhead tank is 5,500 l and that of each of 20/40 hatching jars is 6.35 l.
  • The spawnery comprises two cement tanks (1.8 x 0.9 x 0.9 m each) which can hold a nylon hapa measuring 1.65 x 0.8 x 1.0m, projected above the tank and hence deeper than the tank and has an overhead shower for spray.
  • Each jar can accommodate 50,000 water hardened and swollen eggs at a time. The water flow rate maintained is 600-800 ml/minute for IMC.
  • This was earlier a very successful system, but the hatchery jars are now obtained against orders only.

9. Transparent polythene jar hatchery

  • This hatchery is identical to Bhowmick’s glass jar hatchery except that the breakable hatching jars are replaced by transparent polythene containers.
  • Each jar is provided with an inlet pipe and an outlet pipe and escape of eggs from jars is further prevented by an inner mesquite netting container.
  • Each jar has its water supply inlet pipe going down almost up to the jar bottom which is of concave type, in hatchery jars.
  • The water on reaching the jar bottom is reflected upwards till it finds its exit located at the top of the jars.
  • The water in a jar of this type develops greater churning and suspended eggs therein get better oxygenation.
  • This is perhaps a superior system than the unidirectional flow pattern of Zoug jars

10. Galvanized iron jar hatchery

  • This hatchery resembles Bhowmick’s glass jar hatchery except that the hatchery glass jars are replaced by galvanized iron jars.
  • Each jar has a cylindrical portion (48.5 cm long and 23.0 cm diameter ) and a top conical portion (19 cm long).
  • The jars are filled on an angle iron framework which also accommodates a galvanized iron conduct (10 cm wide and 10 cm high) to carry the hatchlings from the jars to the spawnery.
  • The water flow rate is 1 L/min/jar. The galvanized iron jar hatchery is cheaper than glass jar or polythene jar hatchery.

11. Shirgur’s bin hatchery

  • This hatchery consists of a rectangular aluminum container (54’’ x 16’’ x 22’’) provided with circulating water (243 L/min) in which are placed cylindrical egg vessels (12’’ diameter and 12’’height).
  • Each egg vessel can hold about 200,000 carp eggs at a time.

12. Hanging dip net hatchery

  • This hatchery comprises conical 1/16’’ cloth dip nets (65 cm diameter at top and 46 cm diameter at bottom) provided with a 50mm brass spray head at the bottom of each dip net.
  • Such dip nets are hung in hatching tanks of 3.3 x 1x 1m.
  • The water flow rate is 1-1.5 l /min during hatching and about 100,000 eggs can be hatched in each container.
  • After hatching, the hatchlings pass through the meshes of the dip net and get collected in the tank where they are allowed to remain for 3 days before being transferred to nursery pond.
  • Such units were installed in Orissa State.

13. Circular cistern hatchery

  • This consists of a galvanized iron circular cistern (tank) of 1 m3 capacity with a series of inlet facets placed at 45o at a height of 5 cm from ground level such that when connected to water supply, water moves in a circular fashion.
  • The overflowing water is allowed to leave the cistern from an outlet placed at the top by a monofilament 60 mesh/ linear inch.
  • The hatchlings are left behind in the cistern till their transfer to nursery pond.

14. Chinese type of hatchery

  • To the Chinese goes the credit of developing the concept of circular breeding and hatching tanks in which water shows circular or centrifugal motion.
  • Such hatcheries used for hatching carp eggs in India are of Chinese origin and they are called as the Chinese type of carp hatcheries.
  • This system, within a small space, simulates some aspects of riverine environment and has proved itself a very successful method of breeding carps where commercial production of carp seed is required.
  • In this system, the outlet lies in the middle of the circular tank guarded by a circular perforated structure or a sloping outlet.
  • The principle of a hatching tank is similar to that of a breeding tank, excepting that the former is smaller and normally has two chambers, giving the shape of a double doughnut to the hatching tank.
  • The outlet lies in the middle of the circular tank guarded by a straight, circular perforated pipe which regulates water level in both the chambers.
  • One wall of the double doughnut lies at the periphery and the other at the inner end surrounding the outlet.
  • The water circulates between the two walls in a circular fashion, with the help of water jets/ inlets, placed at 45 degree from the bottom.
  • It is where the eggs are hatched.

15. Low density polyethylene (LDPE) hatchery

  • S.N. Dwivedi, a former Director of Central Institute of Fisheries Education, Bombay was instrumental in introducing LDPE material in fish hatcheries.
    This material, like moulded plastic, is made in one piece, has no joints or welds.
  • This hatchery comprises overhead tanks, cooling tower and compressors. It combines breeding and hatching facilities.
  • Each vertical hatching jar of capacity 40 L can hold 0.2-0.25 million developing eggs.

In earlier days, fish hatchery was used as a facility for hatching of fish eggs collected from rivers and bundhs. At that time, rivers and bundhs were the main sources of carp seed.Over the years the development and refinement of the technique of induced breeding has been enlarged. Hence more emphasis is being given to the hatchery proper for the large scale production of fish fry.
Details on the number of Indian major carp hatcheries (both public and private sector), spawn production, conversion rate from spawn to fry, type of hatchery, spawning agent used, etc. are presented below. It is evident that the Chinese type of circular hatchery is the most widely used hatchery for large seed production all over the country. Jar hatchery (glass or fiberglass) and double-walled hatching hapa are used for medium or small scale operation in some parts of the country. Among the different fish spawning agents, ovaprim, a ready-to-use agent, has been the most popular hormone among fish hatchery operators.

Last modified: Monday, 13 June 2011, 10:17 AM