Production of Yellow Catfish

The yellow catfish or sun catfish, Horabagrus brachysoma primarily inhabits fresh waters and sometimes available in backwaters. It is greenish-yellow in colour on the dorsal side with brilliant gold flanks and a large black spot on the shoulder surrounded by a light-yellow ring. The dorsal and anal fins are yellowish orange in colour and stained dark at margins. The attractive golden colour and peaceful nature makes the fish suitable for ornamental industry.

The yellow catfish is benthic in habit, which has affinity towards mud and sand substrate and is nocturnal in nature. It takes natural shelter inside submerged aquatic plants in the shallow areas of water body. It is an opportunistic benthophagic omnivore, which widens its dietary spectrum in response to the available food.

The yellow catfish has a prolonged breeding season which peaks during June to July, however, an individual spawns only once in a season. It grows to a maximum size of 50 cm and approximately 1 kg weight and the longevity has been estimated as 5-6 years. It is a popular food fish endemic to the Western Ghats and as per IUCN categorization, the fish is classified under “Vulnerable” category. The high fecundity of this species is yet another attribute that makes it an ideal candidate for commercial utilization. The ICAR-NBFGR jointly with Regional Agricultural Research Station, Kumarakom developed breeding and cryopreservation protocol of this species for conservation purpose under NATP-NBFGR Project. Continuous ranching of this fish was carried out under this project and yielded 12% more catch of this species from Vembanad Lake. Subsequently, it was found that fishery of this fish improved in almost all the freshwater areas of Kuttanad region. It is also one of the important fisheries in Kole wetlands in Thrissur, especially during monsoon.

Seed Production

Broodstock management

The broodfish of 80-100 g size are stocked in earthen ponds at a stocking density of 1-2/m². It is weaned on a pelletted feed (30-32% protein) fed at 2-5% of the body weight. The fish can also be fed with wet feeds comprising of fish offal, rice bran and groundnut oilcake

Selection of brooder

The yellow catfish is heterosexual. Sexual dimorphism is apparent among ripe fish only during the breeding season. The male has streamlined body, generally brighter, smaller in size and exude copious milky milt on slight pressure. Amongst catfishes, this is one of the very few species that freely exude milky milt. The male attains sexual maturity in the first year and female in the second year.

The male at 17-18 cm and female matures at 18-19 cm and exhibits synchronous ovarian development. During spawning season, the female possesses swollen abdomen with wide and bright red genital opening whereas the male has rudimentary genital papilla having reddish pointed tip. As the fish has the habit of hiding in dark corners, PVC pipes of 30- 40 cm length and 15-20 cm diameter are put as hide-outs in the pond. It does not breed spontaneously in pond.

Spawning

Male and female fish are selected in the ratio 1:1 by body weight or 2:1 by number and induced to spawn by intramuscular injection of synthetic hormones like Wova-FH at 1-1.5 ml/kg body weight as a single dose. The latency period is 8-14 hours. After 12-13 hours of injection, there is a free flow of eggs on applying gentle pressure on the abdomen. Stripping of the female is done by pressing the belly gently. Similarly, milt is also collected from the male by stripping and that from one male is sufficient to fertilise all the eggs of a female of similar size. Being hardy, the stripped fish regain health fast after stripping and the male has been found to regain milting condition during the same season.The eggs and milt are mixed thoroughly with a feather to ensure good fertilisation rate. The average rate of fertilisation is 60-80% in artificial breeding and the fertilised egg has 1.4 mm diameter.The highest GSI for both sexes are normally observed immediately after the onset of monsoon. The fecundity ranges from 40,000-1,24,000.

Incubation

The fertilised eggs are kept in tubs for hatching, with running water. These are heavily yolked, translucent, golden-yellow in colour and spherical in shape. Hatching is observed in 22-29 hours at 24-26⁰C. The hatchling has a size of 4-5 mm (1-2 mg). The hatching rate is 40-60% and even 95% was achieved at experimental set up at RARS, Kumarakom. The hatchling subsists on yolk for 3 days and later they feed on plankton and artificial diet like egg custard.

Rearing of hatchling & fry

The hatchling is reared in large open nursery hapa (5 m x 4 m x 1 m) fixed in nursery pond. Feeding is done using egg yolk at spawn stage. Powdered compounded feed concentrate is utilized as feed supplements in addition to the live plankton. The characteristic yellow ocellus appeared in one-week old larvae. The 30-45 dph fry are transferred to earthen pond and fed with groundnut oil cake and rice bran mixture feed. The prepared pond is used for stocking of hatchlings @ 50- 100/m^2. The seed attains 6-7 cm in 3 months of rearing.

Farming in Pond

The farming of yellow catfish has not been given much importance till date; however, it is more suitable for smaller homestead pond. Similar sized individuals of native barbs and cichlids could be raised with the yellow catfish. Some of the locally available candidate species like Labeo dussumieri, Systo mussarana and Etroplus suratensis can be cultured together with it. In Kerala, two farming practices are in vogue; extensive systems to produce large adults of over 200 g for the local food market and intensive systems for value addition of fry and fingerlings for the demanding global ornamental trade. Based on its euryphagous feeding habits, yellow catfish is also suitable for integrated farming system. Another attractive proposition would be to use the yellow catfish in predator-prey culture systems using tilapia or other weed fish as forage species.

Source : Department of Fisheries, Government of Kerala