THE CALIFORNIAN SALMON. 
59 
shoals on the San Joaquin, which river it ascends to a 
length of about 100 miles through the warmest valley in 
California ; where the temperature of the air, rarely below 
75 deg. at noon, is often up to 104 deg. As to the water 
of the river, it reaches sometimes 82 deg. at the surface, 
and 80 deg. near the bottom. No other species of migra- 
tory salmon lives in latitudes so far South, as this one. 
Mr. Eedding of the Californian Fish Commission states 
that in July and August when salmon are most abundant, 
the mean temperature of the San Joaquin river is 79*7 deg. 
During the same period the mean temperature of the 
Sacramento calculated over ten years is 73*4 deg. 
“ A point equally important is, that this species does not 
suffer although the water may be somewhat impure; it 
ascends the Sacramento and San Joaquin at the precise 
time when the waters are most affected by the washing of 
minerals, and seems to feel no inconvenience. 
“ The time of spawning of this salmon is prolonged 
excessively, contrary to that of the Salmo salar , and seems 
to last nearly six months of the year. It is known that the 
time varies according to the locality, being earlier in pro- 
portion to the distance from the sea, and near the source 
of the rivers. Thus in the upper waters of the Sacramento 
the spawning takes place in the end of June or the begin- 
ning of July, thirty miles lower down the stream it is 
observed to take place in July and August, and the farther 
down the river, the later is the time of spawning. At the 
junction of the McLeod river with the Sacramento, or 
about 180 miles from the sea, it does not take place till the 
end of August, or early in September ; lower still at 
Tahama, the season is October and November. In some of 
the streams which fall into the sea north of the Sacra- 
mento, such as the Eel River, and the Russian River, the 
spawning takes place in winter, or in December, January, 
and February. 
