A spinning reel spool made lightweight while maintaining the strength of the bobbin trunk. per pixel and processed, an effective tone range of a color image obtained in each of the color image forming layers is 0. Wastewater containing pollutants, such as nitrogen and phosphorus, are fed to the partitioned aquaculture system. The invention further comprises a method for determining a relationship between a stress state of a turbine component and an operating condition of a turbine housing the component.