138 The UMAP Journal 30.2(2009) Table 9 Steady-statenumbers(x10)of species Algae Molluscs Herbivorous Milkfish ( mussels) maximum139220.6249 Minimum132860.6152 06174 07018 Therefore, we can replace the equality conditions among the ri by in- tervals for the steady-state numbers 13286≤m1≤1.3922, 0.6152≤2≤0.6249, 0.6174≤:3≤06233, 07108≤c4≤0.7061 Ve can now use Lingo to solve the equivalent model, with the resul of table 10 Optimal steady-state numbers(x10)of species Algae Molluscs Herbivorous Milkfish (mussels) 0.62 062 The corresponding the maximum harvest value is $115 x10, and the corresponding water quality is shown in Table 11 Table 11. Concentrations of elements (ug/L)after optimization. At optimal 173607-141022 Compared to the water quality required by coral growth, the water quality obtained here is obviously satisfactory, and we reap relatively hig ic benefits at the same time In order to prove the results of our model are correct, we define fishing/harvest index feed cost Then the result we obtained is: fishing/harvest index=0.06%. The actual result is: fishing/harvest index=2.8%0138 The UMAP Journal 30.2 (2009) Table 9. Steady-state numbers (X 104) of species. Algae Molluscs Herbivorous Milkfish (musseIs) Fish Maximum 1.3922 0.6249 0.6233 0.7061 Minimum 1.3286 0.6152 0.6174 0.7018 Therefore, we can replace the equality conditions among the xi by in￾tervals for the steady-state numbers: 1.3286 < x, < 1.3922, 0.6152 < x 2 < 0.6249, 0.6174 < x3 < 0.6233, 0.7108 <-x 4 < 0.7061. We can now use Lingo to solve the equivalent model, with the results of Table 10. Table 10. Optimal steady-state numbers (x 10 4 ) of species. Algae Molluscs Herbivorous Milkfish (mussels) Fish Optimal 1.39 0.62 0.62 0.71 The corresponding the maximum harvest value is $115 x 10i, and the corresponding water quality is shown in Table 11. Table 1L. Concentrations of elements (pg/L) after optimization. Chlorophyll C N P At optimal 0.15 17-36 0.7-1.4 1.0-22 Compared to the water quality required by coral growth, the water quality obtained here is obviously satisfactory, and we reap relatively high economic benefits at the same time. In order to prove the results of our model are correct, we define: flshinhtd -feed cost fishing/harvest index - net income Then the result we obtained is: fishing/harvest index = 0.066%. The actual result is: fishing/harvest index = 2.8%