Publications

The African catfish (Clarias lazera C. and V., 1840) : a new species for aquaculture

Hogendoorn, H.

Summary

Fish husbandry can contribute substantially to the production of animal protein for human nutrition, especially in tropical countries. To determine the suitability of C. lazera for aquaculture, the propagation and production ,management as well as the growth physiology of this fish were studied.

The planned production of Clarias fingerlings can be realized through artificial reproduction, including hypophysation followed by stripping of the females and dissection of the testes of the males to fertilize the eggs. Methods for successful incubation of the eggs and subsequent rearing of the fry to fingerlings are reported.

In growing the fingerlings to marketable size good results were obtained both in extensive pond-farming as well as in high density culture in tanks. Under conditions that prevail in African subsistence fish farming. the Clarias outyield tilapia by more than 250%. Under optimal conditions in tanks they grow more than 200 g in 5 months from birth, while the feed conversion rate (feed/ gain) stays well below unity. The efficient feed conversion is explained by modest maintenance requirements as compared with the maximum feed uptake and feed utilization capacity. The effects of body weight, temperature and feeding level on the growth and feed utilization of C. lazera were studied and discussed. On this basis a feeding guide for the intensive culture of the African catfish was established.