64 DECEMBER 2022 • WORLD AQUACULTURE • WWW.WA S .ORG for broodfish, which was at 5 percent of body weight per day to get good results. Fishes were held under this condition for 5-6 months. Female fish genital papilla became swollen and slightly pink, with a bulging abdomen (Fig. 2). When males were ready for spawning, the pectoral fins became rough (Fig. 2). Free-flowing males and ripe females were selected for breeding in the ratio of 2:3, respectively or equal weight for both males and females. The average size was 16 cm (range 14-18 cm). Preparation of Breeding Tank and Hapa Fish prepared for inducing were held in 4×2×1 ft nylon hapa (3×3 mm) fixed in a 274×91×61 cm cement tank (Fig. 3) with old water with good aeration, a continuous artificial water shower and nylon substrate in the breeding hapa. A piece of fine-mesh nylon net (152×91 cm) was spread horizontally at the bottom of the tank (under the breeding hapa) for removal of unfertilized eggs and shells after hatchlings were out of the eggs to avoid fungal infection. The overall system should be in a semi-dark and silent place. Synthetic GTH Preparation and Injection The synthetic gonadotropin hormone Spawn Pro (50 percent dilution with pure distilled water) was used as an inducing agent. Two tests were performed to establish an efficient dosage. In the first trial, 7 females and 13 males were used. In a second trial, 11 females and 17 males were selected. In the first test, females and males were administered Spawn Pro intramuscularly at 2 mL/kg and 1.5 mL/kg of body weight respectively. In the second test, females were administered 1.8 mL/kg and males were administered 1.5 mL/kg of body weight. The hormone was administered in the evening and fish were then transferred to breeding hapas. Mating started 6-7 hr after administration of the hormone and spawning started within 8-10 hr after injection. Females released eggs and males spread milt over them. When spawning was completed, broodfish were released back into the pond or rearing tanks after a dip in 0.1 mg/L a potassium permanganate (KMnO4) solution to avoid infection. Ompok pabda is a carnivorous Indian freshwater catfish, popularly known as butter catfish or pabda. This fish has a good market value and demand in India. It has fine flesh with a soft meat texture, good taste and high nutritional value and few intermuscular bones. Pabda are naturally found in ponds, lakes, swamps, paddy fields and rivers. In India, it is widely distributed in the plains and sub-mountainous regions. Pabda usually live in the upper level of the water column. They generally eat protozoans, aquatic insects, crustaceans and moss. They also consume seedmeal cakes and fishmeal as a supplementary feed. Over the last decade, wild populations of pabda have undergone a steady decline related to overexploitation, loss of habitat, disease, pollution, siltation of rivers, poisoning and destructive fishing methods. As a consequence, the fish has been categorized as endangered by the International Union for the Conservation of Nature (IUCN). There are few reports on breeding technique of pabda through stripping of female and testis collection of male fish under captive conditions, but non-sacrificial breeding technique of male pabda are rare. This article describes a study that demonstrates successful breeding and seed production of pabda without sacrifice of male fish in an artificial aquatic environment to save and increase the population of this endangered fish species. Broodstock Management Broodfish were collected from instructional farm ponds of Sasya Shyamala KVK and nearby different wetlands of South 24 Parganas district. For genetic improvement/variation of fish, collected fish should weigh 80-100 g (Fig. 1) and stocked in a 9×3×2 ft cement tank with a good aeration system and in a semi-dark place. Water hyacinth was kept at the darkest corner part of the tank so that the fish could shelter there. Live feed, such as Tubifex, zooplankton, small fishes or supplementary feed consisting of 39 percent fishmeal, 15 percent soybean meal, 15 percent rice bran, 10 percent wheat bran, 10 percent groundnut cake, 5 percent starch powder, 5 percent fish oil, 0.03 percent vitamin C, 0.01 percent vitamin E, 2.97 percent of other vitamins and minerals was used in the preparation of feed A Modified Technique for Breeding and Seed Production of Pabda in India Swagat Ghosh, Samiran Patra and Narayan Sahu FIGURE 1. Broodfish of Ompok pabda.
RkJQdWJsaXNoZXIy MjExNDY=