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ZD JOURNAL OF APPLIED AQUACULTURE kg fish/minute; T = 2Q°C, L = 1 I/minute, R = 0.63, D = 61 cm; X = 182 cmz}. Carrying capacity was subsequently calculated after each parameter was increased to ZO% and 40% of its original value. Each parameter was altered individually, while the other parameters were maintained at the standard level. The temperature at which R was determined (Tr}, flow rate at which R was determined (Fr), biofilter cross-sectional area at which R was determined (Xr), and biofilter depth at which R was determined (Dr) were not included in the sensitivity studies, since they would typically be held constant. The values of these parameters in the sensitivity studies were: 20°C for Tr, 8 1/minute for Fr, 182 cmz far Xr, and 61 cm for Dr. Temperature Equation 9 was incorporated into the mode! for the sensitivity studies. Because this equation has not been tested at tem- peratures aver 12.7°C, it may be preferable to use temperature Equation 10 for actual applications of the model involving tempera- tures in excess of approximately 13°C. For the purpose of sensitiv- ity studies, however, either equation is suitable, since both affect the model similarly. The results of the sensitivity studies indicated that ammonia con- centration (C), temperature (T), ammonia removal (R), and ammonia production (A) had relatively large effects on carrying capacity (Table 3). The relatively large effects of ammonia removal (R) emphasize the importance of accurately measuring this parameter. Ammonia con- centration, temperature, and ammonia removal were linearly related to carrying capacity. In contrast, flow rate, biofilter cross-sectional area, biofilter depth, and ammonia production were all nonlinearly related to carrying capacity, indicating that: (1}changes in carrying capacity resulting from changes in these parameters are dependent upon the levels of these parameters; (2) these parameters could have shown larger effects on carrying capacity, had the sensitivity analy- sis been started with a different set of standard values. Further in- vestigation demonstrated that ammonia production (A} had a rela- tively simple influence on carrying capacity: carrying capacity increased with a decrease in ammonia production (A), approaching infinity as A approached zero. The results of simultaneously varying flow rate (F) and biofilter size are depicted in Figure 4. To simplify the presentation of these results, biofilter cross-sectional area (X) and biofilter depth (D)