76 POPULAR SCIENCE MONTHLY. 



THE FISHES OF JAPAN. 



WITH OBSERVATIONS ON THE DISTRIBUTION OF FISHES. 

 By DAVID STARR JORDAN, 



PRESIDENT OF LELAND STANFORD JUNIOR UNIVERSITY. 



THE islands of Japan are remarkable for their richness of animal 

 life. The variety in climatic and other conditions, the nearness 

 to the great continent of Asia and to the chief center of marine life — 

 the East Indian Islands — its relation to the warm Black Current or 

 Kuro Shiwo — the Gulf Stream of the Orient — and to the cold current 

 from Bering Sea, all tend to give variety to the fauna of its seas. 

 Especially numerous and varied are the fishes of Japan. 



About nine hundred species of fishes are known, from the four 

 great main islands of Japan, and about two hundred more from the 

 volcanic islands (Kuriles and Liu Kiu) to the north and south. Of 

 the eleven hundred, about fifty are fresh water. All these are derived 

 from the mainland of Asia. Two faunal districts, the north and the 

 south, may be recognized among the fresh-water fishes. The mountain 

 region and the region lying to the north of Fuji abound in trout, with 

 salmon, sturgeon, lamprey and other northern fishes. In the soiithern 

 district these are absent and the chief fresh-water fishes are ayu, or 

 dwarf salmon, chubs, minnows, cat-fishes and loaches. 



The marine fishes are far more varied, their distribution being 

 mainly controlled by temperature and currents. Among these, five 

 districts may be recognized, their range sufficiently indicated by the 

 names, Kurile, Hokkaido, Nippon, Kiusiu, Kuro Shiwo and Liu Kiu. 

 Of these, the Kurile Fauna is subarctic, similar to that of the Aleutian 

 Islands, that of the Liu Kiu islands is tropical, that of the promon- 

 tories, which strike out into the Kuro Shiwo, is Polynesian. The cen- 

 tral region (Nippon) contains the forms essentially Japanese. Kiusiu 

 lias much in common with China, and Hokkaido with Siberia and Man- 

 churia. Each of these districts overlaps, by a broad fringe, on the 

 others. 



It has been noted that the fish fauna of Japan bears a striking 

 resemblance to that of the Mediterranean, and Dr. Giinther has sug- 

 gested that this can be accounted for by supposing that in recent times 

 a continuous coast line and sea-passage extended from one region to 

 the other, the Isthmus of Suez not existing. 



