The growth of Hizikia fusiformis (Harvey) Okamura was investigated at Waniura, northern part of the Tsusima Islands, Nagasaki Prefecture, from May 1994 to March 1995. Mature thalli were contained in small polyethylene baskets which fastened on the denuded stones. Embryos liberated from the thalli were allowed to settle on the stones around the baskets. The plants developed from the embryos to reach 95 cm long in late March of the next year, smaller than that of the natural thalli 129 cm long which developed from rhizomes. It became clear that H. fusiformis could reach harvestable length in a year under suitable biological and environmental conditions.
