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. We do not know the cause of the poor growth, but perhaps the diet had inadequate amounts of essential vitamins or amino acids. The modified catfish diet seemed to provide adequate nutrition during winter, when water temperatures were below 10 C and energy requirements were low. The slower sinking modified catfish diet may allow the fish extra time to feed in cold water and thereby attain growth similar to that in fish fed higher energy trout food.