Effect of Different Weight Classes of Processed Clarias gariepinus on Yields of Fish Fillet and Fishmeal Production

Four weight classes of African Catfish, Clarias gariepinus (Burchell 1822), - below 500g, 500g 999g, 1.000 kg 1.499 kg and 1.500 kg 1.999 kg - were processed into fish fillets and the by-product into fishmeal. The fillet yields ranged between 31.85 % - 39.50 % with the biggest fish group producing the highest fillet yield but lowest amount of solid waste (58.25 %). There was a direct relationship between fish weight and fillet yield as well as solid waste yield. The fishmeal produced from the solid waste also revealed a direct relationship between the fish weight and the amount of fishmeal produced. The biggest fish group (1.500 kg 1.999 kg), despite having the lowest amount of raw material, produced the highest amount of fishmeal with the best conversion ratio 4.481 (raw fish dried fishmeal). Proximate analysis revealed crude protein range of 55.87 0.16 to 57.40 0.95 with the biggest fish group having the highest crude protein. There were significant differences among the fish fillet, solid waste and drip loss yields of the fish weight classes. Likewise, there was a significant difference between the crude protein and ash contents of the smallest fish group and those of the biggest fish group.