'HE SEAWEED INDUSTRIES OF JAPAN. 



By HUGH M. SMITH, 

 Deputy U. S. Fish Commissioner. 



Seaweeds are among the most valuable of the aquatic resources of the Japanese 

 Empire, and conduce largely to the prominent rank attained by the fisheries of that 

 country. While marine plants are extensively utilized in France. Ireland. Scotland, 

 and other European countries, in the East Indies, in China, and elsewhere, in no 

 other country are such products relatively and actually so important or utilized in 

 such a large variety of ways as in Japan. 



The seaweed industries of Japan owe their importance to the great extent of the 

 coast line (estimated at 18,000 miles); to the abundance and variety of useful algse; 

 and to the ingenuity of the people in putting the different kinds of plants to the 

 most appropriate uses and in utilizing them to the fullest extent. 



The value of the seaweeds prepared in Japan at the present time exceeds 

 $2,000,0(10 annually, this sum excluding the value of very large quantities of marine 

 plants which do not enter into commerce but are used locally in the families of the 

 fishermen. 



In view of the extent and long continuance of these industries, some diminution 

 in the supply of economic algae might reasonably be looked for, and this has in fact 

 occurred; but while excessive gathering has influenced the abundance of some species, 

 much more serious decrease has been brought about by conditions not connected with 

 the seaweed industries. Investigations conducted by the imperial fisheries bureau 

 have indicated that the disappearance of useful alga' on a number of sections of flic 

 coast has resulted from a temporary freshening of the littoral waters, probably owing 

 to improper lumber operations near the headwaters of streams. The denuded areas 

 have always been contiguous to the mouths of rivers or within the possible range of 

 influence of streams during freshets. It is reported that in a few places certain algae 

 have been able partly to reestablish themselves, but the process is very slow, and 

 complete replenishment will require many years, even if no lowering of water 

 density ensues in the meantime. Some experimental planting in the denuded 

 districts has been undertaken with favorable results, but on a very small scale. In 

 other parts of Japan cultivation is extensively carried on, but as yet is directed to 

 practically only one species, the laver {Porphyra laciniata). 



It is noteworthy that the disappearance of seaweeds has injuriously affected 

 another fishery — namely, that for abalones, which rank among the important water 

 products of Japan. These mollusks feed among the alga- and are no longer found 

 on large areas of bottom on which they formerly abounded. 



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