Biomass and production of macrobenthos in the Seto Inland Sea Japan

Abstract

Secondary production by macrobenthic communities in the Seto Inland Sea was estimated to be 0.19-11.2 gC/m2/year. The highest production (>10 g C/m2/year) was observed in the north shore area of Osaka Bay, which was characterized by abundant organic matter in the bottom sediment. Macrobenthos production in deep (>20 m) and sandy bottom sediments tended to be higher than in shallow and muddy bottom sediments. Macrobenthos production in almost all areas of Harima-nada, Hiuchi-nada, Hiroshima-Bay and the west area of Suo-nada was less than 1 g C/m2/year. It is suggested that the biomass of macrobenthos in the north area of Osaka Bay, central areas of Hiuchi-nada and Hiroshima Bay in the Seto Inland Sea have decreased compared to the values estimated 10-15 years ago.