366 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 5 



wegian Sea. Currents flowing through these passages are deflected 

 to the right by the revolution of the earth, a current as a rule follow- 

 ing the right-hand shore, whether it is passing north or south. The 

 water passing to the north warms the right-hand, or eastern, side, 

 and there temperatures at which the halibut can live prevail ; whereas 

 on the western side of each passage the cold currents pass south, and 

 temperature falls so low as to prevent its occurrence. There is, 

 therefore, across the Atlantic a zone or belt of halibut banks tend- 

 ing to lie on the eastern side of each passage wherever currents of the 

 warm Atlantic waters penetrate and touch continental shelves. They 

 were found on the eastern side of Davis Strait between America 

 and Greenland, the southern and western side of Iceland, near the 

 Faroes, and on the Norwegian coast, and even in the Barents Sea 

 where it is warmed by a branch of the Gulf Stream pressing to the 

 right around the North Cape of Norway. 



In the Pacific the Commission found the same temperature rela- 

 tionship. The bitterly cold waters of the Okhotsk Sea and the 

 northern Bering Sea prevent the occurrence of halibut in numbers. 

 On the Asiatic side the warm northward-flowing Japanese Stream 

 approaches closely to the Arctic waters of the Okhotsk, and in the 

 short stretch of coast line opposite the Island of Hokkaido, where 

 the transition from cold to warm occurs, the halibut finds suitable 

 waters lying above 3° C. Passing to the eastward over the North 

 Pacific, the Japanese Stream is continued by the wind currents, 

 rendering temperate the long coast line between California and 

 Bering Sea. There 2,000 miles of coast line have bottom temperatures 

 between 3° and 8° C, and in accordance with the size of this great 

 area a great fishery exists. 



Curiously enough, this distribution corresponds closely to that 

 already found by the biologists for certain small invertebrates, which 

 they call boreal organisms, living in the tempered water between the 

 Arctic and Atlantic Oceans.^ The halibut may therefore be called as 

 boreal fish, if its occasional occurrence far outside its normal range 

 be ignored. 



Because of this distribution and its limitation by the physical con- 

 ditions of the ocean, it has not been possible to find new banks in- 

 definitely. There came a time when the increase in efficiency and 

 the ability to travel great distances brought the fishermen to the 

 natural limits of the halibut distribution. In the Atlantic this devel- 

 opment culminated in great mother ships, with their own cold stor- 

 ages and fleets of small boats. They could remain at sea for long 

 periods, independent of the shore and able to exploit the most distant 



« Broch, HJalmar, Einige Probleme der blogeographischen Abgrenzung der arktischen 

 Region. Berlin. Univ. K. Zool. Mus. Mitteilungen, Bd. 19, 20 p. The Museum, 

 Berlin, 1933. 



