Estimation of the Optimum Water Temperature Occurring Maximum Larval Fish Species in the Korean Coastal Waters

Number of larval fish species in the temperate waters is severely changed depending on the spawning ecology of fishes and seasonal changes of water temperature in the Korean coastal waters. In this study, we estimate the optimal water temperatures for occurring maximum larval fish species per the unit volume in the one coastal area of the East Sea and two offshore area of the Yellow Sea using Harmony Search Algorithm. The optimal water temperatures are in the range of 23.5 to 25.0 °C. The estimated optimal water temperatures do not show significant differences between the East Sea and the Yellow Sea. When water temperature was over the estimated optimum temperature, the number of larval fish species was decreased more rapidly. Number of larval fish species was rapidly increased when the water temperature was more than 18 to 22 °C, of which ranges was slightly wider than the estimated optimal water temperature. As the water temperature will reach the optimum earlier by global warming, the maximum number of larval fish species will occur earlier than the before, and the number will decline in the month of higher than the optimal water temperature.