sumers" demand, and Japan is capable of increasing 

 its supply with the increase of the consumers" de- 

 mand, ifthe following technical problems are solved: 

 1 ) How to prevent a bad crop, and 2) how to improve 

 the quality of the products. 



There is another problem which has arisen, the 

 spreading of industrial pollution. Coastal waters be- 

 came polluted and nori products became contami- 

 nated with cadmium, mercury, etc. We are afraid we 

 may need hygienic control in the future if pollution 

 increases. 



The most important problem in nori culture is 

 found in its administration, income of the cultivators 

 increased more quickly than that of city laborers, but 

 in recent years this is not so. The increase came from 

 the rise in nori prices and also from the increase in 

 the harvests. In the future the rise in the prices can 

 be expected, but the increase in the harvest will 

 cause oversupply. The mechanization of the culture 

 processes is raising the cost of nori. especially in the 

 case of small-scale operations. 



The technique to store live nori buds in cold stor- 

 age is also used for cropped nori plants. This will 

 inevitably stimulate the development of factories 

 which store cropped nori and make it into products 

 far more efficiently than each fisherman can. Until 

 now, the income of a cultivator was the sum of 

 harvest plus manufacturing, and if the latter is re- 

 moved, he must recover his loss by production in- 

 crease. 



In the near future nori cultivators will be divided 

 into two groups, the majority going into mass pro- 

 duction using the floating system and the minority 

 going into small-scale operations producing nori of 

 special quality. 



The number of cultivators has been kept at a level 

 of 60.000 in the past 20 yr. but this level will decrease 

 with the scale-up of each operation. Substitution of 

 cultivators will occur, and cultivators who combine 

 farming will decrease and ones who combine fishery 

 will increase. 



Under these changes of circumstances, the tech- 

 nical problems will be: 



1 ) How to prevent cultivation from a bad crop? 

 A bad crop is generally caused by outbreaks of 

 diseases, and techniques to forecast and prevent 

 the outbreak of diseases are expected. 



2) How to simplify each culture process? The 

 present processes were developed for small-scale 

 operations. They have to be modified to fit the 

 need of a large-scale operation. 



3) How to improve the qualities of the products? 

 Development of an effective fertilizing technique 

 will be expected. 



4) Breeding of nori and introducing foreign 

 Porpliyrci will be helpful for items 1-3 — nori with 

 more resistance to diseases, nori of higher produc- 

 tivity, perhaps of not maturing under winter's 

 short-day conditions, and nori of higher quality, 

 making the product more glossy, w ith more odor 

 and better taste. A variety off. teneni is highly 

 productive and resistant to diseases but of lower 

 quality. 



5) Techniques for mass manufacturing of crop 

 products. 



WAKAME (UNDARIA) 



Biology 



"Wakame" is a seaweed peculiar to Japan and 

 Korea, and 60.000 tons of this raw seaweed are 

 landed annually. 10.000 tons in dry weight. Cur- 

 rently cultivation extends the seaweed industry to 

 the northern areas, now including many districts all 

 over Japan. The output from cultivation was over 

 60,000 tons in 1970. 



The seaweed grows from beginning of winter to 

 spring, then dies out after liberating zoospores. 

 Within 20-40 days several hundred million spores 

 come out from one plant. The spores germinate im- 

 mediately to a microscopic filamentous alga, which 

 lies dormant during the summer, in the fall, when the 

 water temperature goes below 20°C. egg and sper- 

 matium are produced, germinate, and grow into the 

 wakame plant. This seaweed grows to several mil- 

 limeters long in 1 mo. 10 cm in 2 mo. and 1-2 m long in 

 3-4 mo. The temperature at the northern limit of 

 distribution is 2°C in the winter and at the southern 

 limit. 14°C. 



Cultivation 



Historical Reviews 



in 193.*^ Kanda found that the life history of 

 wakame was almost the same as that o\' hiiiiiiuirin. 

 its cultivation started in the 1940"s along the coast of 

 southern Manchuria, together uith that of 

 luiiiiliuiriii, where their natural growth is almost 

 zero. 



.•\fter World War ii. the industry was introduced 

 into China w hich produced 30,000 tons of raw prod- 

 uct a year, most of which isLaminaria. Meanwhile 

 in Japan, the cultivation did not develop because of 

 sufficient supply of natural products. 



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