industries drawing workers away from the 

 fisheries, with the resultant rising labor costs, as 

 much of the growing, harvesting, and processing 

 of the nori must be mechanized as possible. Even 

 so, the nori fishery is not suffering nearly as se- 

 vere a problem as that facing the oyster fishery. 



4. Eutrophication in the coastal areas around 

 Japan. This, in fact, is going on, and it may pro- 

 vide nutrients to the nori cultivating areas to 

 some e.xtent, but most of the causative elements 

 of coastal eutrophication such as industrial dis- 

 charge, domestic sewage, and agricultural run- 

 off contain undersirable constituents. Industrial 

 pollution, particularly that which contains cad- 

 mium, mercury, and other highly toxic elements 

 poses a much greater threat to nori cultivation. 

 Pollution of all kinds is now a very serious prob- 

 lem for Japan, but their heavy dependence on 

 seafood, much of which comes from their coastal 

 waters, makes marine pollution a very real health 

 and economic threat. 



5. Potential for oversupply with its resultant 

 economic effects. With the high prices, the 

 growers are obviously attempting to increase 

 their total production. The success of efforts to 

 expand the nori growing areas, solve the disease 

 problems, eliminate pollution problems, and 

 mechanize the industry will all lead to increased 

 production. Further, the growing tendency of 

 separating the producers and processors into 

 separate operations will cause the producers to 

 grow more algae to maintain their income level. 

 Another possibility is that with the increasing 

 mechanization and increasing size of cultivation 

 operations, fewer workers and separate 

 operators will be needed. Thus, many nori 

 fishermen will be moved into other types of em- 

 ployment. 



VNDARIA (WAKAME) 

 Introduction 



In comparison to nori, cultivation of the brown 

 alga, Utnhiriti. is of relatively recent origin. The 

 amount of wakame grown is still significantly less 

 than nori, but is increasing rapidly from almost zero 

 production in 1963 to over 60.000 tons in 1970. This 

 exceeds the amount being harvested in Japan from 

 natural beds. This alga, one of the Laminariales. is 

 not native to .American waters. 



Culture Techniques 



In the spring when the mature plants release the 

 zoospores, "collector strings"" are hung in the water 

 on which the spores attach and the sporophytes 

 grow. As with nori, this seeding now takes place in 

 tanks although in the past it was done in the sea 

 near natural beds. Also, past efforts to expand the 

 beds have included creating new substrate surface 

 by dropping rocks onto the bottom and exploding 

 existing rocks with dynamite in areas with natural 

 populations of Unclaria. A wide variety of other 

 techniques have been experimented on over the 

 past 55 yr with some success (Tamura, 1966). 



However, currently the collector string method is 

 used in which the mature sporophylis are partially 

 dried, placed into the tanks of fresh seawater and 

 the released zoospores settle on a lOO-m long string, 

 previously wound around a vinyl plastic frame. The 

 frame is removed after 1-2 hr and transferred to a 

 l-m deep culture tank for the summer season. When 

 the young plants reach about I mm in length (in the 

 fall), the strings are transferred to rafts in the sea. 

 The plants are harvested when they reach about 1 m 

 in length. 



Attempts to produce hybrids of three species of 

 Undarin have met with some success, indicating 

 that at least closely related species can be crossed 

 (Saito, 1971). 



Problems 



If the strings are placed on the rafts before the 

 water temperatures have dropped to 15°C, serious 

 fouling can occur. Also, if the rafts are located in a 

 rough water area and left floating on the surface, the 

 young plants can be seriously damaged. In these 

 areas the rafts can be anchored to a depth of 1 m to 

 avoid this problem. Other problems which are not so 

 easily remedied include some bacterial diseases and 

 grazing of the young plants by isopods and gas- 

 tropods. One last potential problem is the indication 

 that production is increasing to the point of equal- 

 ling, if not exceeding, the demand for wakame in 

 Japan. 



LAMINARIA (KOMBU) 

 Introduction 



Many species of this genus are used by the 

 Japanese as food: several of them being cultivated at 

 the present time. While important as a food and as a 



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