First Record of Induced Spawning of Magur (Clarias batratus) Without Sacrificing Male Fish in Bangladesh

Abstract

Background and Objective: Clarias batrachus is an important freshwater fish of Bangladesh and is locally known as Magur. It has great commercial value due to its taste and economic aspect. This study was undertaken to establish the natural spawning of Clarias batrachus in captive conditions. Materials and Methods: The experiment was conducted at the hatchery of Bangladesh Fisheries Research Institute, Freshwater Sub-Station, Saidpur to determine the reproductive response of Clarias batrachus using different types of hormones. The average length and weight of brood used for the breeding trial was (26±2.0 cm an average weight of 160±4 g) and female (average length of 24±3.0 cm and an average weight of 210±6.0 g) Clarias batrachus . To detect ovulation, fertilization, spawning, hatching and survival different doses of the hormone were used due to optimizing the hormone doses. Results: After 24-28 hrs of injection, natural spawning was found successful in all cases except in T 1 . The case of PG (20 mg kg G 1 for females and 10 mg kg G 1 for males with ovuhom 1 mL kg G 1 for females and 0.5 mL kg G 1 for males) shows better results in terms of ovulation, fertilization and hatching and survival in T 3 rathe than T 2 . In the higher dose, almost 100% of fishes spawned naturally and fertilization and hatching rates were also higher. Hatching of fertilized eggs occurred between 30-35 hrs of incubation at 27 to 28 E C and the larvae started to feed within 72 hrs after hatching. Conclusion: This is considered a landmark in the strategy of saving this male from sacrificing, by establishing this technique for mass production of fry Clarias batrachus.