A practical investigation into catfish (Clarias gariepinus) farming in the Vaalharts irrigation scheme

[摘要] English: A practical investigation into factors influencing the success of catfish (Clarias gariepinus) farming in the Vaalharts Irrigation Scheme was undertaken. These factors were production, nutrition, disease, disease treatment, processing and marketing. Flow-through tarpaulin ponds in the Vaalharts Irrigation Scheme were used very successfully for the propagation and rearing of Clarias gariepinus. The growth rate of Clarias gariepinus fingerlings stocked in an irrigation dam and a tarpaulin flow-through pond was determined and compared. The highest specific growth rate (1.61% bw/day) of fish in the irrigation dam coincided with the highest average monthly water temperature (26°C) recorded during the month of January 2005. The specific growth rate of fish in the flow-through ponds was lower (<1.27% bw/day) than that of fish in the irrigation dam. Fingerlings stocked at an average size of 8.9 g in the irrigation dam reached a size of 450 g within 216 days. The nutritional value and feed conversion rates (FCR) of two feed formulations were determined and compared. The percentage protein of these two feeds was 22.07% and 33.50%, respectively. Higher percentage feed protein levels coincided with better feed conversion rates. Except for an outbreak of white spot disease (Ichthyophthirius multifiliis) in one hatchery pond, no significant mortalities of fish were recorded as a result of parasite infestations. Parasitic infestations were successfully treated in the Vaalharts hatchery using prophylactic formalin bath treatments. Fish processed yielded a fillet dressout percentage of 40%. Consumer resistance for catfish products were found in urban markets. In the semi-urban informal settlements, however, catfish were readily accepted.

[发布机构] University of the Free State