著者

船木 實 大槻 一枝 大野 正夫

出版者

日本応用藻類学会

雑誌

Algal Resources (ISSN:18833284)

巻号頁・発行日

vol.14, no.2, pp.29-47, 2021 (Released:2022-12-30)

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In the years 1932-52, Yoshiro Otsuki, while living in China, investigated how to cultivate Saccharina japonica var. japonica (Makombu) and Undaria pinnatifida (Wakame) in the Yellow Sea area in China. In 1938 he was able to develop a seeding method that could release numerous numbers of zoospores from mature Makombu and Wakame within several hours by stimulating the seaweed through partial drying of their thalli also known as “dry stimulation method ”. Consequently, he was able to establish the complete cultivation of Wakame using the raft cultivation method near the sea surface. However, Makombu has to be submerged on the seabed during the summer season because of too high temperature. Otsuki solved this problem by cultivating the gametophyte stage in the oligotrophic seawater below the sea surface and by this treatment, the gametophyte stage developed some form of resistance against environmental change. He was able to establish the complete cultivation technique of Makombu in 1952. However, he was not able to apply the technique in commercial scale in China as he had to return to Japan in 1953, just after being released from detention by the Chinese government. In Japan, he started the cultivation of Wakame in Onagawa, Miyagi Prefecture as soon as he returned home. This time he succeeded in the commercial cultivation of Wakame. Some Chinese researchers have evaluated his contribution to the establishment of cultivated technology of Makombu in Yellow Sea, where it does not grow naturally. Unfortunately, Otsuki's achievements have been almost unknown to the Japanese-both to the general public and the fishermen.

著者

大房 剛

出版者

日本応用藻類学会

雑誌

Algal Resources (ISSN:18833284)

巻号頁・発行日

vol.4, no.1, pp.15-21, 2011 (Released:2021-06-03)

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From October 2008 to April 2009, the domestic production of Nori, Porphyra spp, amounted 9,106 million of sheets in Japan, while only 402 million sheets were imported from other countries. That is, 95% of Nori demanded in Japan, has been produced domestically. On the contrary, the import ratio of other seaweed, such as Wakame, Undaria pinnatifida, and Hijiki, Sargassum fusiforme has been quite high. Japan imported over 80% of its annual Wakame demand and approximately 90% of its annual Hijiki from Korea and China. Recently, however, in Japan many problems have been occurring in the edible seaweed industries field in terms of the price which has been kept lower, a skewed age composition of fishermen which is mostly consisted of the aged, and decreasing number of the fishermen. In regard to Wakame and Hijiki, how to maintain the current import volume must be a key issue. It is, therefore, very important to collect the information about cultivating condition of Wakame and Hijiki in Korea and China.