Succession of Seaweed Communities on Artificial Reefs in the Inlet of Tosa Bay, Japan

Abstract

A total of 14 artificial reefs were set on the sandy bottom of the Ikenoura Inlet, Tosa Bay, at the depth of 7m, in December of 1990.
A qualitative survey of seaweeds was carried out on the artificial reefs for four years. Brown algae Colpomenia sinuosa dominated after three months of placement, but two months later they disapeared. The number of species increased conspicuously on the blocks thereafter. A total of 42 species of seaweeds were recognized on the artificial reefs after two years. The main algae on the blocks were Ulva sp., Codium fragile, Sargassum micracanthum, Padia arborescens etc., which was similar to that of the algal flora of the inlet of Tosa Bay. The biomass of seaweeds was 3004.5g wet weight m^-2 in June of 1994. However, most seaweeds showed a cyclical pattern of abundance with disappearance on summers.