수온과 사료공급횟수에 따른 넙치(Paralichthys olivaceus)의 암모니아 물질 수지 모델 평가

Abstract

Olive flounder (Paralichthys olivaceus) is one of the most important aquaculture fish species in Korea and has the advantage of being fast growing and farmed at high density. It accounts for about 56% of domestic farmed fish production, which is of great importance to the domestic aquaculture industry. However, due to persistent pollution in coastal areas, the mortality rate in flow-through fish farms, which produce aquaculture organisms by taking a large amount of natural seawater, is increasing sharply. Similar problems are occurring all over the world, and to solve them, research is being conducted on a recirculating aquaculture system (RAS) that is not affected by the environment like existing marine cages or flow-through water methods. In designing a RAS, the water flow rate of the system is determined by calculating the mass balance based on the biological load for various water quality factors. One important factor affecting water quality and fish productivity is total ammonia nitrogen (TAN). Accordingly, an experiment was conducted in this study to derive a TAN mass balance model for olive flounder as a function of water temperature (20, 23, 26 ℃) and feeding frequency (1, 2, 3, 4 times/day). As a result, the higher the water temperature and the lower the feeding frequency, the higher the TAN excretion of flounder. In this way, a specific TAN mass balance model for olive flounder was developed as a function of water temperature and feeding frequency. The weight-specific TAN excretion model formula for olive flounder was Z=348.82+(-6.8538214e+10)ℯ-X-0.57Y3. The model formula for specific excretion of ingested nitrogen TAN was Z=63.06-18320.04/X2-0.0412Y3. In both models, the X value is water temperature and the Y value is feeding frequency. A model predicting the ratio of excreted nitrogen to ingested nitrogen and a TAN mass balance model were used to establish a design criterion for predicting the water flow rate to maintain the appropriate TAN concentration required in the aquaculture system.