Taishugyo, fish popular with the public that are captured in large amounts and end up daily on our kitchen tables, are small pelagic fish that feed on zooplankton. While taishugyo are often referred to as magusa (grass eaten by horses or cows) fish, they are better referred to as carnivores rather than herbivores. In the ecological system, they are produced from condensing 100 times the solar energy provided by phytoplankton. Taishugyo show large variations in resource production, with the size of the variation depending on the ecological characteristics of each fish species. The resource management of Taishugyo, which sees large-scale natural variations, is an important issue to be addressed.