GEOGRAPHIC DISTRIBUTION OF THE PACIFIC SALMON 
687 
the warm and saline waters of the North Sea. The failure of the California chinook 
salmon to develop sea-run populations in the streams tributary to these seas is con- 
sistent with their failure to develop natural populations under similar conditions in the 
South Pacific region. 
The mean temperatures and salinities of the coastal waters in the areas of the 
North Atlantic (see figs. 2, 3, and 4), where the Alaska and California salmon have 
failed to establish natural nms, are beyond the ranges of temperature and salinity 
found in the native marine habitats of these salmon. The areas in which they have 
been successfully established all have coastal waters with temperatures and salinities 
similar to those in the native marine habitats of the salmon. In other words, the 
reactions of the Pacific salmon to both fresh-water and marine environmental condi- 
tions in the North Atlantic are consistent with their reaction to similar conditions 
in the South Atlantic and South Pacific regions. 
SOUTH ATLANTIC REGION 
The only attempts to introduce the Pacific salmon into the South Atlantic region 
have been those made in the waters of southern Argentina, which have apparently 
failed. The streams of Argentina, with the possible exception of those in southern 
Patagonia, receive a great deal of drainage from plateaus and are essentially alluvium- 
bearing streams with sandy and mud bottoms. Since it is known that the Pacific 
salmon do not spawn in sandy- or mud-bottomed streams, nor coidd the eggs survive 
under such conditions even if so spawned, it is not surprising that sea-run populations 
have failed to develop from the transplantations in these streams. Marini (1936) 
also reports unfavorable high temperatures in some streams in which the salmon were 
transplanted. Complete surveys have not as yet been made of all the streams in 
Patagonia in which the salmon have been introduced. There may still be streams in 
the southern extremity of this province that will support natural runs which are at 
present unknown. 
The mean directional drifts of the currents, the mean seasonal surface tempera- 
tures, the mean annual subsurface temperatures (200 meters), and the mean annual 
surface salinities for the South Atlantic, are given in figures 1-4, inclusive. These 
data were taken from the oceanographical studies of Buchan (1894), Schott (1926), 
and Church (1934). The hydrographic conditions of the coastal waters of Patagonia, 
as given in these figures, are in every case similar to those found in the native marine 
habitats of the salmon. Hence, it appears that the failure of the attempts to intro- 
duce these salmon in Argentina lies in the unfavorable environmental conditions in 
its fresh waters. 
SUMMARY 
The native distribution of the Pacific salmon (genus Oncorhynchus ) is confined 
almost entirely to the temperate waters of the North Pacific. They are found in 
varying degrees of abundance along the North American coast from Monterey Bay, 
Calif., to Kotzebue Sound, Bering Sea, and along the Asiatic coast from the Anadir 
River, Siberia, to the Tumen River, Korea, and Cape Inuboye, Honshu Island, 
Japan. They also occur in isolated streams along the Arctic coast. 
