The ratios of the quantities of elements recovered in lettuce tissue, fish tissue, and solids to the quantities of elements provided in the diet are listed in Table 3 and illustrated in Fig. 4. The upper lines in each graph in Fig. 4 represent the sum of the percents of dietary nutrients recovered in lettuce tissue, fish tissue, and solids; sums exceeding 100% of dietary nutrients indicate that nutrient removal exceeded nutrient production by fish resulting in a reduction in dissolved nutrient concentration.