124 
BULLETIN OP THE UNITED STATES FISH COMMISSION. 
The spring run passes upstream quite rapidly, reaching their spawning-grounds 
on the McCloud River in about six weeks after entering the river at Collinsville. 
The fall run moves more slowly. They are about two months reaching their 
spawning-grounds, which are not so far upstream. The flood and ebb tides are more 
nearly equal, owing to the smaller amount of water coming from the rivers, making 
the passage of the salmon through the bay a little longer. The nets of the fish- 
ermen also offer a greater obstruction during the low water and in this way hold 
the salmon back. In 1900 salmon were taken in abundance in Suisun Bay and 
in the river as far up as Rio Vista- by the middle of August, but were not taken 
at Sacramento until after the fii'st of September. The low water doubtless made the 
movement slow, and the taking of from 2,000 to 10.000 daily out. of a slow run would 
account for their nonappearance at Sacramento. 
Upon reaching the shoals in the middle portion of the river they cease their 
migration, having already found good spawning-grounds. In 1898, 1899, and 1900 
the water was normally low and a large proportion of the salmon. found spawning- 
places in the main river. The early high water and frequent fall rains in 1897 sent 
them into the tributaries. 
The latter part of September, 1901, 150 salmon were weighed and branded with 
serial numbers and released in the river near Rio Vista. Three of these were taken 
at the hatcheries the latter part of November, just at the close of the season. The 
following is a particular account of these three specimens: 
No. 8, a female, was branded September 20, when it weighed - 3,930 grams. It 
was taken again at Mill Creek fishery November 23, when it weighed 10,180 grams, 
having been 64 days on the road and having lost 26 per cent of its weight. 
No. 91, also a female, was branded September 24, when it weighed 8,470 grams. 
It was retaken at Mill Creek November 20, when it weighed 7,160 grams, its time in 
passing up the river being 56 days and its loss in weight being 15 per cent. This 
specimen was returned to the creek after being weighed November 20. It was 
found dead on the racks 8 days later, when it had spawned all but 20 of its ova. 
Its weight had decreased 1,860 grams. 
No. 43, a male, was branded September 20, when it weighed 10,080 grams. It 
was taken at Battle Creek November 25, when it. weighed 6,275 grams, making its 
time from Rio Vista 66 days and its loss in weight 25 per cent. 
This important experiment proves that the fall salmon travel very slowly, at a 
rate of 4 or 5 miles a day, and require about two months to reach the spawning- 
grounds from the month of the river. 
The salmon of the spring run arrive at their spawning-grounds from two to six 
weeks or even longer before they are ready to spawn. This time they spend lying 
quietly in the pools. The fall salmon are more nearly ripe when they reach their 
spawning-grounds. Indeed, it is probable that many of them cease to ascend the 
streams only when they are ready to spawn. 
Downstream movement . — Under ordinary conditions there is probably little or 
no downstream movement, yet when the salmon meet with such obstructions as the 
racks at the fish-culture stations, there is a tendency to go back downstream. At 
Battle Creek fishery more salmon are taken at the lower end of the pool than at 
the upper, indicating that they go as far downstream as possible under the circum- 
stances. The large number of fishes in good condition that get caught on the rack 
