Ompok bimaculatus (Bloch, 1794) popularly known as ‘Butter Catfish’ or ‘Pabda’ is an Indian freshwater catfish with good market demands particularly in North- Eastern part of India. It has fine flesh with a soft meat texture, good taste and high nutritional value and low in bones. It dwells and breeds in the rivers and reservoirs. It is commonly sold fresh locally or ice preserved. It is of high consumer preference in the entire east and North- Eastern states of India and fetches high market value as Rs 300-400/kg. It is generally cultured in ponds along with carps, but rearing in shades and deserted ponds is not uncommon to be seen. Culture of pabda can be taken as a profitable, commercially viable enterprise by the rural youth. Despite great potentiality, culture of this species has not yet received due importance. It has not received much attention in recent aquaculture scenario mainly due to non-availability of information regarding its breeding and larval rearing technique. Successful captive breeding can go a long way to improve socio-economical conditions of farmers.
It is a naturally breeding cat fish and collection of pabda seed from water bodies and that too in required numbers and as per demand is practically impossible. Dearth of technological skill is elicited as major constraint to accept this venture. On the other, indiscriminate use of pesticides in the paddy field, the main breeding ground of pabda also endangers the species. Further, various anthropogenic activities have resulted in shrinkage of breeding ground. The major challenges found in the seed production in captivity is the lower survivability of larvae during its rearing due to high cannibalism, low acceptability towards artificial diet, undeveloped digestive system etc.
To overcome the problems of pabda seed availability, effort was made by the College of Fisheries, Lembucherra to produce pabda seed in low cost backyard seed production unit. A three days training programme on pabda breeding and larval rearing has been organized with 12 fish farmers from various parts of Tripura. One young farmer named Santanu Das, Rajnagar, South Tripura started the breeding programme immediately after going home with the existing facility in his home. He could earn the revenue of Rs. 5300.00 within a span of 26 days and the amount spent by him was Rs. 1110.00.
The farmer used pabda that were about one year old and weighing about 100 g. each. Fully ripe females and males were segregated and used in induced breeding. Females can be distinguished by a rounder, fuller abdomen and smooth pectoral fin whereas males have pectoral fin with serrated hard fin ray at dorsal fin.
The brood fishes are kept overnight in unfed condition so as to evacuate their stomach. Ovatide is used to promote induction of spawning. Ovatide was applied at 2.5 ml/kg body weight for females and 1 ml/kg body weight for males, applied in a single injection intramuscularly.
Females were stripped for spawning 8-10 hours after hormone injection and the eggs were collected in a dry aluminum tray. Simultaneously, testes were removed by dissecting the male and kept on a piece of cloth. The testes were then squeezed over the eggs on the tray and mixed well with help of a feather followed by addition of water to activate the sperm for fertilization. Then pieces of testis or any tissue from the eggs were removed. The fertilized eggs were then transferred to plastic container with or without net buskets for incubation.
Then the fertilized eggs were spread on a nylon net kept in a series of plastic tub provided with or without aeration at 5 cm depth from the water surface. The water depth is maintained at about 12-15 cm. The eggs hatched out within 24 hours of the fertilization and emerged as yolk sac larvae. Newly hatched larva was reared in the tub itself.
Water levels were adjusted at different stages of rearing to minimise the stress to larva. Aquatic weeds such as Hydrilla were provided to give shelter for the larvae. Yolk sacs were absorbed in around three days. Live tubifex, mixed zoo plankton, chopped earthworm and egg custard were provided as larval feed upto 15th day. Plankton were collected from ponds at morning or evening time by a plankton net. The collected plankton was filtered through a fine net. 2-3 ml of plankton per litre water was sufficient for larvae. The dead zooplankton were removed by siphoning at least once a day.
In fry stages and onwards the fish were fed with boiled fish muscle (preferably low fibred). The average size of fry was 2.5-3.0 cm in 21 days of rearing. The seed produced is ready for stocking.
Removal of testes by the Fertilization by stripping Pabda fingerlings produced
farmer method by the farmer
Mr. Santanu Das used 12 nos. brooders (6 female; 6 male) which he had in his pond. The survival percentage was overwhelming in the context of village level production system, as this stage is regarded as crucial in pabda seed production. The economics of the activity is given below:
|Aerator and accessories||200.00|
|Seed produced||1600 x 4 = 6400.00|
This low cost pabda breeding technology practiced by the farmer will open the vistas of income generation of the rural youth as well as it may help to provide pabda seed to the fish farmers of the Tripura to enable them to take pabda culture as an alternative means of self employment. This technology can be replicated in other states too, making a major breakthrough in fishery sector of the North east India.