The present production of fingerlings in the country has been assessed to be 989.84 lakhs of which 50.20% come from rearing of spawn and fry 48.75% from riverine collection and 1.05% from Bundh breeding. (Fish seed committee report, 1966).
Carp, eggs, after fertilisation swell to the size of a pea and are non-adhesive and demersal. The specific gravity of eggs is slightly higher than that of water.
Fish Seed From Natural Sources
Riverine collection of major carp spawn still remains to primary source of spawn, its contribution to the total production in 1964-65 being as much as 91.67 %. Riverine collection has obvious limitations beyond a certain level of exploitation and is very much dependent on several ecological and meteorological factors.
The seed of major carps namely Catla (Catla Catla) Rohu (Labeo rohita) and Mrigal (Cirrhina mrigala) and of some medium carps as well, are collected during the monsoon months, when the mature fish ascend the flooded rivers and breed on finding suitable ecologcial, meteorological and climatological conditions.
Collection of Eggs
Where actual breeding grounds have been located the eggs are scooped out from shallower grounds by means of rectangular pieces of mosquito netting of varying sizes.
However, from fast flowing waters they are collected by Benchi jal (conical bag net). The collection of carp eggs at Naizira on river Dhikhow in Sibsagar, Assam, where special technique was adopted to collect the eggs from very fast flowing river, has been stopped due to the success met by induced breeding technique.
Collection of Spawn
Carp spawn which emerge out of the eggs in 18 to 24 hours and measure 5-7 mm.in length, are collected by means of a specially devised gearthe Benchi jal (Shooting net).
The shooting net differs with regard to its size, shape, material and construction in different States. The larger ones are made out of mosquito netting cloth, conical in shape and open at both ends, measuring about 24 feet in length and having a mouth diameter of about 18 ft.the later may be provided with two lateral wings to widen the receptive area of the mouth. The cod end, measuring about 9"-12" in diameter, is provided with a cane or bamboo ring which gives it a stable shape during the operation. Detachable piece, 2 ft. x 1 ft., the Gamcha made out of fine muslin cloth, is attached to the cod end during the operation to serve as a receptacle.
Classification of Fish Seed:
In Midnapore district of West Bengal, the dimensions of spawn collection nets are: length of net proper 320 cm, width at mouth 312 cm., height at mouth 61 cm., ring diameter 23 cm., length of gamcha 168 cm., height of gamcha 62 cm.and width at rear end 44 cm.
Method of Operation
The net is fixed to bamboo poles in shallow waters with gentle flow, the mouth facing the current but with its upper lip a little above the water level, the cod-end drifting in the direction of the current in which position it is fixed to poles just below the water surface. The gamcha is then tied to this end with its hind end tied to another pole. The drifting spawn are led through the wings and body of the net into the gamcha, from where it is periodically removed for temporary storage in small pits or happas (cloth tanks), which are rectangular in shape and made of fine muslin cloth. These are fixed with the help of four bamboo poles and care is taken to see that its upper edges always remain a few inches above the water level. Care should be taken to see that the happa does not rest on the bottom mud, nor does its bottom float in water because of the presence of air bubbles.
Collection of Fry and Fingerlings
Spawn apart, fry and fingerlings are also collected from the rivers.
Some State undertake the collection of fingerlings also from below the irrigation or pick up weirs (Punjab and Madhya Pradesh) or from paddy fields (Andhra and Tamil Nadu).
The fry and fingerlings are collected by fry collection nets, which are fine-meshed drag nets. The fingerlings are also collected by cast nets, traps of fine muslin cloth, while they jump over to cross the irrigation barriers. Basket traps are used for collecting fry and fingerlings in the rivers Godavari, Krishna and Cauvery.
Natural Fish Seed Resources
Fish seed in Andhra Pradesh is obtained in the State both through riverine collection and through induced breeding with pituitary hormones.
Regarding the seed of major carps, collection from riverine sources is restricted to the spawn and fingerlings only. They are collected from Godavari, Krishna, Manjira and Muai river system and their major tributaries. Riverine collection of spawn and fingerlings of major carps during 1964-65 were 360 and 24.75 lakhs respectively.
River Brahmaputra and her tributaries constitute the natural fish seed resources of Assam; but the quality of seed encountered in the tributaries is reportedly very poor. A negligible portion of the States total fingerlings production (0.09 lakh in 1962-63) is obtained through riverine collection.
Bihar constitutes the most important State of the country in so far as natural spawn resources are concerned. Fish spawn in the State is obtained almost fully from riverine resources in Bihar, Son and Kosi and their tributaries. It is believed that the Ganga spawn generally comprises 75% major carps, of which mrigal form 50% and Catla and Rohu 25% each. The Son spawn generally comprises 50% major carps, of which mrigal form 60%, Rohu 25% and Catla 15%. The Kosi spawn generally comprises 50% major carps. The riverine collection in 1964-65 amount to 1000 lakhs., while of 1965-70 and 1985-90 were 4569 and 1222 lakhs spawn respectively.
Production of fish seed in Delhi is almost completely restricted to the collection of major carp fingerlings from Yamuna river, which yielded 6-10 lakhs per year.
80 lakhs of spawn and 10 lakhs of fry were collected from riverine sources in 1964-65 in Gujrat State. Rivers like Narbada, Mahisagar yield high quality seed with over 80% of economic species.
313.22 lakhs of spawn, 1.77 lakh of fries and 1.86 lakhs of fingerlings have been obtained in Madhya Pradesh through riverine collection in 1964-65. They were collected at 6 cetres on river Narbada on Garva Nalla (a tributary of river Betwa) three centres on river Asan, one centre each on the rivers Swarnarekha, Jarina (a tributary of river Chambal) and Narbada.
Riverine collection of spawn in Mysore State is confined to a single centre on river Dudhganga in Belgaum district, where the collection of fry and fingerlings from natural sources are confined to two to four centres on the same river. The collection of spawn and fry during 1964-65 were 9.60 and 3.91 lakhs respectively.
Collection of spawn and fry from a natural sources is carried out at 15 main centres on the rivers Mahanadi, Brahmani and Subarnrekha. 1342 lakhs of spawn and 1.05 lakhs of fry were collected from riverine sources during 1964-65.
In Pondicherry fingerlings of major carps were collected from rivers and streams in Karaikal and Yanam to the extend of 1.45 lakhs during 1964-65.
Riverine collection of spawn and fry in Punjab was taken up for the first time in 1963 and of all the different methods riverine collection is already yielding maximum quantity of fish seed to the tune of 32.89 lakhs of spawn and 23.04 lakhs of fry in 1964-65. Rajasthan could not collect spawn and fry from riverine sources, but collect fingerlings of major carps from rivers (20.41 lakhs collection in 1964-65). Riverine collection centres are located all over the State on rivers Channel, Banas, Dai, Ghambhir, Gomti, Tabra, Ruparail, Parbati and their tributaries.
Major carp spawn in Uttar Pradesh are obtained mainly through riverine collection. Spawn are collected at about 150 centres on the rivers Betwa, Chandmovinala, ganga, Ghagra, Gomti, Huiden, Isun, Krishna, Ramganga, Rapti, Sahnadi, Sai, Sarda, Sarjoo, Son and Yamuna, while the fry are collected at eight centres on the rivers Ghagra, Ganga, Sarju and Son 821.66 lakhs of spawn and 5.12 lakhs of fry were collected from riverine sources during 1964-65. In 91-92, the riverine spawn collection of the State accounts for 65.73 lakhs.
In West Bengal spawn area collected at several centres on the river Ganga, Padma, Bhagirathi and Damodar. Estimated spawn production in the State from riverine sources appear to be 11,583 lakhs.
Bundh-breeding, which is prevalent only in the States of Madhya Pradesh and West Bengal, accounted for 5.38% of the total fish seed production in the country. It is however, reported that wet bundhs are existent in certain parts of Andhra Pradesh, Uttar Pradesh and Bihar, wherein breeding of major carps reportedly takes place; but no definite information as to their occurrence and magnitude is available with the concerned State Governments.
Location and distribution: A dry bundh has been described as a shallow depression enclosed by an earthen wall (locally known as bundh) on three sides, which impounds fresh rain water from the catchment area during the monsoon season. Such impoundments, which remain more or less dry during a greater part of the year are known as dry bundhs.
The topography of the land has a great role to play in the location and distribution of dry-bundhs. The undulated land, which provides a large catchment area and facilities for quick filling of the bundhs even with a short rain and at the same time quick and easy drainage due to gravitation, in the Midnapore and Bankura districts of West Bengal has specially favoured the construction of large number of such bundhs in the private sectors. In Madhya Pradesh, dry bundhs are mainly distributed around Nowgang in Chhatrapur district, where topography of the land and the soil type are almost similar to that in the two districts of West Bengal referred to above.
Wet Bundh Breeding
A wet type of bundh is a kind of small or large perennial pond or tank, from a few acres to over a square mile, in the midst of a low-lying and bounded on three sides by high embankments. In summer, generally a quarter part of most of these bundhs dries up and is cultivated, with the central part, deeper than the surrounding area, always contains some water and harbours mature fish. During the monsoons, when water from the upland areas rushes towards the central part in the form of streamlets, the fish move in the shallower ground and breed, from where the eggs are collected and hatched in cloth or mud hatching pits.