Succession of seaweed communities on artificial reefs at Muronohana, Ikata, Japan

Abstract

Artificial reefs for the development of valuable fishery resources were placed on the sandy bottom at 8, 10 and 13m depths in Muronohana, Ikata, Japan. They were observed mon thly or bimonthly from February 1999 to June 2001. Enteromorpha intestinalis and Colpomenia si nuosa dominated the reef in spring, and several species of Melobesioideae dominated during su mmer and autumn. E. intestinalis and C. sinuosa were found to be typical primary colonist. The number of seaweed species at all the sites gradually increased in winter. In total, 38 seaweed s pecies were found from all the reefs, over the study period. Each reef was dominated by Sarga ssum spp., Ecklonia kurome and Padina arborescens within 18 months of the placement. The se ttlement of kelp, such as E. kurome, was promoted by reduced sand cover as a result of turbul ence. These results indicate that large-scale surface roughness, and/or kelp knobs, could be imp ortant in maintaining the communities after initial establishment.