Individual lengths and weights were determined for a sample of 20 fish per pond every 56 d and at harvest, after 11 months of feeding. Fish in each pond were hand-counted to accurately determine the percentage surviving at harvest. Parenthetic numbers are SDs. However, there were significant differences in weight and condition factor between fish fed diets 1 and 2 at most stocking densities, and there were significant interactions between diet and density for fish weight and condition factor at harvest. Fish fed diet 1 were significantly larger and had higher condition factors than fish fed diet 2.
Parenthetic numbers are SDs.
However, fish fed diet 1 began increasing in weight in May faster than those fed diet 2 and were significantly larger in July and October than those fed diet 2. Condition factors were significantly higher in July and October in fish fed diet 2 than in fish fed diet 1. Parenthetic numbers are SDs. Values with the same letter within each month are not significantly different between diets. This is consistent with the physiological principle that the protein and lipid requirements may decrease as fish become larger.