686 
BULLETIN OF THE BUREAU OF FISHERIES 
The warm silt-bearing streams of southern Europe, in which efforts were made to 
establish natural runs of chinooks, do not provide the conditions essential to the sur- 
vival of these fish. It is not surprising that the transplantations in these streams were 
unsuccessful. However, the failure of the chinooks to develop natural runs in the 
rivers of northern Europe cannot be logically attributed to this cause. 
Figures 1-4, inclusive, give hydrographic data for the North Atlantic Ocean similar 
to those given for the other oceanographic regions. These data were calculated in 
the same manner as in the other regions and were taken from the works of Rathbun 
(1882), Townsend (1901), Nansen (1913), Bigelow (1917 and 1933), Sandstrom (1918), 
Bjerkan (1919), Huntsman (1921), Dawson (1922), Schott (1926), Zeusler (1926), 
Smith (1928), Church (1932, 1934, and 1936), Helland-Hansen (1933), and Parr (1933). 
The mean directional drifts in figure 1 show the general movements of the North 
Atlantic waters from June through September, the period during which the spawning 
migration of the salmon occurs in this zone. Three major currents dominate the 
waters of the North Atlantic; namely, the Gulf Stream or Florida Current, the Labra- 
dor Current, and the East Greenland Current. 
The North Equatorial Current, banking up the waters in the Caribbean Sea and 
the Gulf of Mexico, gives rise to a strong current, the Gulf Stream, which flows out 
of the gulf through the straits between Florida, Cuba, and the Bahamas. This 
current follows the coast line of Florida and Southeastern United States until it reaches 
Cape Hatteras. Here it turns more to the eastward toward the banks of Newfound- 
land, thus allowing a cold current from the north to bathe the shores of Canada and 
the United States as far south as Cape Hatteras. However, the influence of this cold 
current is not appreciably effective south of Cape Cod. South of the banks of New- 
foundland the Labrador Current meets the Gulf Stream. This cold current has only 
a minor influence on the Gulf Stream as it continues eastward toward the coast of 
Europe. 
The cold current which bathes the Northeastern shore of the United States is not 
a continuation of the Labrador Current, but originates in the Gulf of St. Lawrence. 
As it leaves the gulf it turns southward and effectively carries waters of low tempera- 
ture and salinity to the shores as far south as Cape Cod. It is interesting to note at 
this point that the Pacific salmon have not developed natural runs in the coastal 
streams south of Cape Cod. Here again, as in the North and South Pacific regions, 
the occurrence of natural runs of these salmon is associated with the presence of ocean 
drifts bearing waters of low temperature and salinity. 
As the Gulf Stream follows its eastward drift toward the coast of Europe it 
branches into a number of lesser currents whose warm waters greatly temper the 
areas influenced by them (see fig. 1). The major branch passes to the northward of 
the Faeroes and flows toward and along the coast of Norway, where it divides and 
sends branches to Spitsbergen and the Barent Sea. A portion of the Gulf Stream 
also flows around Scotland and enters the North Sea. Other branches penetrate the 
English Channel and bathe the shores of France, Spain, and Portugal. 
The North Sea, which averages considerably less than 200 meters in depth, is 
readily influenced by the warm and saline waters of the Gulf Stream. The Baltic 
Sea, being likewise very shallow, warms rapidly in the summer months, and the waters 
flowing from it during this period fluctuate around 17° C. Furthermore, all of the 
fish in the Baltic Sea area migrating to and from the open ocean must pass through 
