Abstract: The effects of feeding amount (30, 38, 46, 54, 62, 70, 86, 102, 120, 140, 160, 180, 200, or 240 mg/d)on weight gain and water quality including suspended material level, chemical oxygen demand (COD) and ammonia nitrogen (NH+4-N) was studied in aquaculture of Schlegel’s rockfishSebastesschlegeli. Results showed that the growth of the fish was shown to increase with increase in feeding amount ranging from 30 mg/d to 160 mg/d. However, the fish had no weight increment when the fish was fed at a feeding amount of greater than 160 mg/d. The relationship of feeding amount with apparent suspended substance apparent COD levels and apparent ammonia nitrogen levels was found to be highly consistent with the relationship of feeding amount with weight gain. There existed an excessive feeding indication point,SZ, a COD pollution indication point,CZ, and an ammonia nitrogen pollution indicating pointNZ. When the feeding amount was belowSZ,CZandNZ, the apparent suspended material level, apparent COD level and apparent ammonia nitrogen level were increased slowly with the increase in feeding amount; when the feeding amount was found aboveSZ,CZandNZ, however, apparent suspended material level, apparent COD level and apparent ammonia nitrogen level were increased rapidly. Self-purification in aquaculture water was the same as general water. The feeding amount(T)- apparent suspended material level(S) model was established:S=-18.86+1.082T-0.0069T2+0.0002T3; feeding-apparent COD level excretion model: COD=0.16+0.977T-0.055T2+0.00017T3; and COD-self-purification model:C=113.4exp(-0.68t).
2012, Vol. 27 
