In this paper, ecological relationship between seaweed / seagrass bed and fisheries production is discussed on the results of correlation analysis between fisheries catch and the area of seaweed / seagrass beds of the Seto Inland Sea. In the analysis, the area of coastal ecological components (seaweed / seagrass beds, tidal flats and shallow (<10m) sea areas) and fisheries catch data was prepared from the past governmental statistics for the nine sub-sea areas (Suo-Nada, Iyo-Nada, Aki-Nada, Bingo-Geiyo-Seto, Hiuchi-Nada, Bisan-Seto, Harima-Nada, Osaka-Bay and Kii-Channel) in the Seto Inland Sea. The distribution patterns of these ecological components were quite different among the sub-sea areas, which show the Seto Inland Sea comprises diverse environmental and ecological characteristics. A number of positive correlations were detected between the area of these ecological components and fisheries catches, e.g., catches of Japanese flounder, fine spotted flounder, red sea bream, black sea bream, rock fishes (Sebastes spp.), sea urchins and turban shell (Turbo cornutus) with Zostera or Sargassum bed areas. The ecological roles of seaweed / seagrass beds to support coastal fisheries production was discussed, with referring to the extinction of these beds which the Seto Inland Sea has experienced in the past several decades.
