Some studies on care of nile catfish during artifical propagation and the rearing of newly hatched larvae

Summary:-The care of Nile catfish were studied during artificialpropagation. Results obtained under experimental conditionmentioned could be summarized in the following:1- The suitable source of brood Nile catfish and thesuitable time of spawning are determined.Comparative results showed that brood fishes reared fromfingerlings to maturity and artificially spawned atmiddle spawning season gave the best results.2- The HCG dose for artificial propagation which gavebetter. ovulation.and’a•.highest percent of fertilizationwas 2~ I.U/g of fish body weight.3- Behavioural responses of female Nile catfish areinfluenced by anesthetic concentration and exposure time.chloralhydrate concentration from 9.5-15.5 g/gal. of watergave good resul ts when exposure time was 40-25 minutesrespectively. Mortalities occurred when highconcentration of anesthesia and longer exposure time wasallowed.4 - The suitable female stripping time of Nile catfish afterhormonal treatment which resulted In high percent offertilization was 20 hrs. post inoculation.S- The effect of water salinity on hatching and survival oflarvae showed that, with increasing salinity level from