Improvements in the large scale artificial propagation of the sharptooth catfish, Clarias gariepinus (Burchell), in South Africa

Induced spawning procedures developed under local conditions in the Transvaal for the sharptooth catfish, Clarias gariepinus, using a combination of the chorionic gonadotrophin Chorulon with pituitary gland homogenate from the European common carp, Cyprinus carpio, or from C. gariepinus donors, are described. Egg-hatching procedures in which the glutinosity of the fertilized eggs of C. gariepinus are first neutralized using a full-cream powdered milk solution and then hatched in funnels, are compared with a method in which the eggs are directly transferred to nylon screens in trout-hatching trays after fertilization. The hatching trays proved superior and the advantages of this method are discussed