Artificial propagation and larval breeding tests of the african sharptooth catfish, Clarias gariepinus conducted in captive conditions

Abstract

The African catfish Clarias gariepinus is the second most cultured species in many African countries, including Senegal. Despite its economic importance in local aquaculture, artificial propagation of the species that would allow obtaining quality seed throughout the year has not yet been mastered adequately. This study aimed at producing C. gariepinus quality and mass supply seed to enhance local production. Three different types of incubation (Macdonald's bottle, water lettuce and wire mesh frame) were tested to identify the most efficient and accessible method for the producers at low cost and with a high hatching rate. The hatching rates obtained for the three different incubation methods were 26.9%, 10.0% and 6.3% for the Macdonald bottle (MB), wire frame (WF) and water lettuce (WL), respectively, while the corresponding survival rates were 91.6%, 70.4% and 77.8%.77.8%. The high hatching rate obtained with the MB could be due to the influence of permanent water circulation, which is absent in the other two hatching systems. The survival rates decreased 15 days after hatching and were 3.24%, 2.04% and 7.16%, respectively. The survival rates obtained three days after hatching were satisfactory, but the significant decrease at 15 days after hatching especially during the post- weaning phase seems to be due to the food quality, and unrelated to the hatching system. The daily individual growth, weight gain and body size of the larvae was significantly higher for larvae fed with natural food compared those that received artificial food. These results indicate that larvae preferred and fed the natural food which was permanently available in the rearing tanks. The artificial food deposited on the bottom of the tank changes appearance over time and may not be appreciated and efficiently consumed by the larvae, which may negatively impact their growth performance.