Construction of Artificial Seaweed Beds; Using the Spore Bag Method

Kelp forests and Sargassum beds not only are commercially important in themselves but also play an important role in spawning, breeding and feeding grounds for many kind of fish, shellfish, lobster and other important fisheries resources (Komatsu et al. 1982; Komatsu 1985; Ohno et al. 1990; Watanuki and Yamamoto 1990; Terawaki et al. 1998). The distributions of kelp forests comprising of the Ecklonia and Eisenia species are restricted to warm-water regions. A number of ecological studies on these plants have been undertaken with particular attention focused the re-establishment of kelp forests. This is due to declining populations that are a result of various factors, including human activities (Tsutsui et al. 1996). Thus, there has been development of construction techniques of artificial foundation, for kelp forests, and transplanting techniques of seed and adult marine algae, on artificial foundations (Hasegawa et al. 1995). Techniques of formation for seaweed bed may fall under either of the following classifications: 1. Spore dispersal technique; 2. The spore bag technique; 3. Ropeseeding technique; 4. Adult-plant transplantation method; 5. Concrete blocks; 6. The threading technique; 7. Gravel-bag technique; and 8. Transplantation of young plants (Largo and Ohno 1993). In this study, we used the spore bag on the roof of an artificial iron reef and a natural rock for a seaweed bed. The present paper describes the formation of seaweed beds by the spore bag method on an artificial iron reef and a natural rock (habitat).