66 DECEMBER 2022 • WORLD AQUACULTURE • WWW.WA S .ORG Water Quality and Larval Management Water quality parameters are important during spawning and hatching period. Hardness 55-60 ppm, alkalinity 125-130 ppm, temperature 28-30 C, pH 7.5-8.5 and DO 6-7 ppmwas best for spawning, embryonic development and leading to better hatching rate. It is important to provide a good environment for the larvae. So, indoor rearing tanks were provided with continuous aeration, siphoning and 10 percent water exchange per day. Otherwise, there was a chance of mortality and poor growth of larvae related to poor water quality and environment. In the event of cannibalism, segregation of the stocked spawn based on size was necessary and was accomplished by grading through different size of mesh nets. Pabda prefer darkness, so hiding places must be provided for better growth and survive. Water levels were adjusted at different stages of rearing to minimize stress to larvae. Aquatic weeds, such as hydrilla, water hyacinth or date palm tree leaves were provided to give shelter for the larvae. Conclusion First we used the traditional male sacrifice breeding method for pabda breeding and seed production. We faced two major problems: the lack of male fish and lower fertility and production rates. This new breeding technology easily solved these problems and ranching about 30,000 pabda seed in different natural wetlands of South 24 Parganas to protect pabda from extinction. This low-cost breeding technology will also open a new source of income for farmers, farmwomen, self-help groups, rural youth to self-employment and it may help us take one step forward to fulfill our goal. Highlights • Broodfish of 80-100 g are stocked at 2-3/m2 and fed 39 percent of protein pelleted feed at 2 percent body weight twice a day. • Injection of 2 mL/kg body weight of females and 1.5 mL/kg body weight of males with synthetic hormone is sufficient to induce ovulation. • Maintenance of water quality through aeration, siphoning and water replenishment during larval rearing is important to reduce stress in larvae, leading to enhanced growth and survival. • Hiding places must be provided for better growth and survival. • Larvae can be reared at 1000-1500/m2 for 15-20 days in indoor conditions for better growth and survival. • Stocking at higher density leads to sudden mortality and reduced growth. • Tubifex squished into very small pieces and small zooplankton should be provided during the initial phase of larval feeding and then gradually weaned to live Tubifex and finally compound feed. This husbandry practice stimulates fry to accept feed immediately after release into nursery tanks during fingerling production, which ultimately increases growth and survival. • Because of high cannibalism character segregation of bigger fry is important at periodic intervals results in greater growth and survival. Acknowledgment The author gratefully acknowledges to Dr. Arun Kumar Dhar, Professor, Director, Aquaculture Pathology Laboratory, School of Animal and Comparative Biomedical Sciences, The University of Arizona for his helpful guidance for broodstock and health management during the entire research. Notes Swagat Ghosh, Sasya Shyamala Krishi Vigyan Kendra (SSKVK), Ramakrishna Mission Vivekananda Educational and Research Institute (RKMVERI), Arapanch, Sonarpur, South 24 Parganas, West Bengal, India, Kolkata-700150. swagotor@gmail.com Samiran Patra, Krishi Vigyan Kendra, Milebasa (Digha) Kalukhali, Murshidabad, West Bengal. Narayan Sahu, Sasya Shyamala Krishi Vigyan Kendra (SSKVK), Ramakrish Mission Vivekananda Educational and Research Institute (RKMVERI), Arapanch, Sonarpur, South 24 Parganas, West Bengal, India, Kolkata-700150. References Alikunhi, K.H., K.K. Sukumaran, and S.C. Banerjee. 1964. Preliminary observation on commercial breeding of Indian carps under controlled temperature in laboratory. Bulletin No. 3. Central Inland Fisheries Research Institute, Barrackpore, India. Alok, D., T. Krishnan, G.P. Talwar and L.C. Garg. 1993. Induced spawning of catfish, Heteropneustes fossilis (Bloch), using D-Lys6 salmon gonadotropin-releasing hormone analog. Aquaculture 115(12):159-167. American Public Health Association (APHA). 1998. Standard methods for the examination of water and wastewater. 19th ed. American Public Health Association andWater Environment Federation, Washington, DC. Chakrabarty, N.M., P.P. Chakrabarthy and S.C. Mondal. 2008. Embryonic development of Pabda (Ompok pabda) with notes on its farming. Fishing Chimes 26(1):135-137. Chakrabarty, N.M., P.P. Chakrabarthy, and S.C. Mondal. 2006. Mass seed production of pabda and their farming – a challenging step for sustainable utilization of vulnerable fish species. Fishing Chimes 26(1):135-137. Purkayastha, S., S. Sarma, U. Kumar, Sarkar, Wazir, S. Lakra, S. Gupta and S.P. Biswas. 2012. Captive breeding of endangered Ompok pabda with Ovatide. Journal of Applied Aquaculture 24(1):42-48. Swagat, G., N.C. Sahu and F.H. Rahaman. 2020. Breeding and seed production of the stinging catfish in India. World Aquaculture 51(3):67-74. This article describes a study that demonstrates successful breeding and seed production of pabda without sacrifice of male fish. The synthetic gonadotropin hormone Spawn Pro (50 percent dilution with pure distilled water) was used as an inducing agent. The lack of male fish and lower fertility and production rates was solved with this new breeding technology.
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