684 
BULLETIN OF THE BUREAU OF FISHERIES 
mon have established natural runs. Similar mean temperatures are also found in the 
coastal waters near the native limits of occurrence of these salmon in California. 
Hence, from these observations in New Zealand, it may be assumed that the Cali- 
fornia chinooks react unfavorably to temperatures beyond the ranges found in their 
native habitats, but that they tolerate surface salinities of higher values up to 35 
parts per thousand which is the maximum found throughout the entire native range 
of the Pacific salmon. 
Further demonstration of the unfavorable influence of coastal waters of high 
temperature and salinity on the marine survival of these salmon may be found in 
the failure of the attempts to introduce them into the streams of Hawaii, Australia, 
and Tasmania. The upper reaches of the streams in these countries have been fav- 
orable to the introduction of trout, whose fresh-water requirements are similar to 
those of the salmon. In fact, the salmon eggs shipped to these countries, according 
to correspondence received, Baird (1878), McCulloch (1927), and Tasmania Fish- 
eries Commission (1933 and 1935), were hatched without considerable loss and the 
young reared successfully to the stage of seaward migration. Landlocked populations 
of chinooks have been established in the Great Lake of Tasmania but no adults have 
ever returned from the plantings in the rivers, although chinook eggs were also im- 
ported from New Zealand for stocking them. No adults have ever returned from the 
many plantings of salmon made in the rivers of Australia and Hawaii. 
The mean directional drifts in figure 1 show that Hawaii, Australia, and Tas- 
mania are completely surrounded by currents of tropical origin during the spawning 
and seaward migration periods of the salmon. Schott (1935) shows that this same 
condition also prevails throughout most of the year. The mean isotherms and iso- 
halines given in figures 2, 3, and 4, show that in general the surface and subsurface 
temperatures and surface salinities of the coastal waters of these countries exceed the 
values found in the native marine habitats of the salmon. The mean surface temper- 
ature during the spawning migration period appears to be an exception in the case 
of Tasmania. This may indicate that all marine conditions must be favorable before 
survival of the salmon is possible. 
The attempts to introduce sockeye and coho salmon from Washington and 
Oregon into the waters of southern Chile have been successful. The coastal streams 
of southern Chile are similar in origin and character to the streams of southeastern 
Alaska. The climates of the two regions are also quite similar, being characterized 
by heavy rainfall and comparatively mild temperature. The hydrographic conditions 
of the waters along the southern coast of Chile (see figs. 1-4) are also similar to those 
in the native marine habitats of these salmon. The returns, thus far, of adult salmon 
have been reported only in the most southern streams in which transplantations were 
made. This does not mean, however, that other streams in the region are not suit- 
able for the establishment of natural runs, but merely that no returns have as yet 
been reported in them. It is for this reason that areas of both success and failure 
have been indicated on the distributional charts in figures 1-4. The successful trans- 
plantation of sockeye or coho salmon in Chile supports the conclusion that environ- 
mental conditions in both the marine and fresh waters of a foreign region must be 
similar to those in the native habitats of the salmon before successful introduction 
may be expected. 
