Captive Breeding and Embryonic Development of Butter Catfish (Ompok bimaculatus, Bloch 1794), a Threatened Fish of Indian Sub-continent in Northern India

The captive breeding of butter catfish (Ompok bimaculatus, Bloch 1794), a threatened silurid of Indian sub-continent was successfully carried out at the National Bureau of Fish Genetic Resources, Lucknow. Ten induced breeding trials conducted on the fish revealed that the fish can be naturally spawned in controlled conditions using sGnRH analogue and dopamine antagonist. The most suitable and economical dose estimated was 0.7 ml kg(-1) body weight for female and 0.5 ml kg(-1) for male. The latency period for spawning was 7-8 h at temperature 27 +/- A 0.5 A degrees C and fertilization and hatching rates were found in the range of 75-90 % and 80-90 % respectively in flow-through system. The egg hatched out in 21 +/- A 1 h post fertilization (hpf) at temperature 27 +/- A 0.5 A degrees C and yolk-sac was completely absorbed in 48 hpf. The larval survival reduced considerably after 5 days and was recorded 10.4 % after 10 days rearing, reason being, poor food acceptability and cannibalism. The fish responded well when injected with hormonal doses within 36 h of procurement from the pond but thereafter did not respond probably due to stress factor. These trials may be useful in standardizing the ex-situ breeding protocols for O. bimaculatus.