34 MIGRATION OF ADULT SOCKEYE SALMON. 
the rate of progress through brackish water to average 7 or 8 miles 
per day and that through fresh water to be between 15 and 20 miles 
per day. These figures apply only to the spring run on the Sacra- 
mento River. The migration of the fall run is considerably slower, 
averaging but 4 to 5 miles per day through the fresh water. Greene’s 
observations were, of course, made upon fall run fish. 
A further analysis of data has shown some interesting variations in 
the rate of migration. A calculation of the mean rate of migration 
from each marking station indicates that the rate of travel decreases 
as the fish approach nearer the mouth of the Fraser River as follows: 
Station B, 10.5; station C, 7.9; station D, 9.1; station K, 4.5. 
Finally the rates of migration for different parts of the season have 
been calculated. Data given in Tables 1 and 2 were first con- 
densed into quartiles and then into halves, and the rate of travel in 
miles per day was calculated for each of these. The positions of the 
quarter points determining the quartiles were based on the number 
of fish marked, not on the number returned. In adopting a central 
point on which to separate the halves it was rather arbitrarily deter- 
mined to consider all fish marked during July as belonging to the first 
half and all those marked during August as belonging to the second 
half. It is more convenient to think of the halves as separated in this 
manner, and the central point separating the fish marked into halves 
comes sufficiently close to the 1st of August to warrant the division 
on this basis. These calculations have not been made for stations 
C and E nor for any cases based on less than 10 individuals or show- 
ing a retrograde migration relative to the mouth of the Fraser 
River. The inaccuracies in the marking record at station C would 
have made such treatment valueless. In the case of station E, over 
78 per cent of the fish recovered were taken in Canadian waters. 
Inasmuch as the authors were unable to make a detailed analysis of 
the Canadian records, it has seemed best not to attempt too detailed 
an analysis of the records obtained from the marking at station E. 
TABLE 23.—RarTE in Mites PER Day IN DIFFERENT QUARTILES—RETURNS FROM 
Sration A, By Reatons. 





Oo 
i 2 6 i 8 9 10 ; wv) 
wes bre or fetiiiera dad Tiamiitsers) patent evens Gea 
Quartiles. 3 ; Sree S 
&| So || eo (a | we le] oe le] ele] oe te] le] eB lS 
WiTstiewsecees od 6.1 932.1. 8.) 12.2}, 6113.91] 8-],11.3 |, 2) 1004) 5) 22.0) 5) 19.0 35]. 13.0 
Second. 25.3. 350 2 GSI, 81 SOU Sil Os Cele eae See ON} eOoaaee Haeos: 33 | 10.0 
MPhirdees ett 1 | 10.6°)24 11258 6] 12.5] 13] 11.41/13 |10.0] 2] 11.6 5 | 10.4 44 11.1 
IWOurLN. 6285... 14.0) | 25S eb sO nS. Ose 6a ees, | oa econ, 23 | 14 


a Harmonic mean. 
Tape 24.—Rarre 1x Mites PER Day IN DirreRENT HAtvyES—RETURNS FROM 
Sration A, By Reaions. 






© 
1 2 6 7 8 9 10 . iv) 
a | 3% 
Balvesserr ing. | : et pease 
i] oO 
S| me |e] eo le] me le Oe lO Le] OR] OB a i<4 
Mirst_ Peeve. 9] 12.1) 11110.3]18] 9.8/19]} 9.7]15] 8.9] 10] 13.0] 10] 13.6 92] 10.5 
SeCONG. = 22 cea 3] 13.0) 5|14.8] 5]14.8|13]18.7]10117.3| 3/120] 4] 86 43} 14.8 


a Harmonic mean, 
