Fishery bulletin of the Fish and Wildlife Service - NOAA

282 SALMON OF THE KAKLTJK RIVEH, ALASKA
íun or which are fall run seaward migrants. The percentage occurrence of marked
fish of each age group is fairly constant throughout the season, indicating that proportionate
numbers of the two runs are marked.
EXPERIMENTS IN 1926
A total of 47,691 seaward migrant red salmon were marked by the amputation
of two fins. Two combinations were used, the adipose and right ventral, and the
adipose and left ventral. Since approximately the same number of fish were marked
each day by each mark, the data can be grouped together and considered as one
experiment or divided according to the marks used and considered as duplicate
experiments. Although the experiments were carried on simultaneously, the one in
which the fish were marked by the amputation of the adipose and right ventral fins
will be referred to as the first experiment, and the one in which the fish were marked
by the amputation of the adipose and left ventral fins will be referred to as the second
experiment.
Commercial fishing was limited in 1929 and the run of that year could not be
adequately sampled to detect the presence of marked fish. Consequently, no accurate
means of determining the number of three-ocean fish returning from these experiments
is available. The number of marked fish returning and the percentage return,
as presented, are lower than they would have been had information on the threeocean
fish been available.
In the first experiment (table 31), 25,000 seaward migrants were marked, 740
marked fish were recovered and a calculated total of 5,151 marked fish returned from
this experiment, not counting the marked fish returning during 1929. The return
from this experiment was at least 20.6 percent.
j_
Age of seaward migrants
marked
3 1
4
Total
Calculated
n urn her of
each age
marked
TABLE 31.—Data for the first 19S6 marking experiment
02
10,196
6,641
71
26,000
Age of fish
returning
from 1926
migration
ï Based on Incomplete data, see text.
4j
fit
4i
61
fll
ï6,
6,
7.
6»
7»
Calculated
number of
each age
group examined
1,609
2,690
168,042
4.627
44,204
279
221,311
Number of
marked fish
of. each age
group found
1
6
498
11
219
в
740
Percentage
occurrence
of marked
fish In flsh
examined
0.066
• .186
.296
.243
.49«
2.161
Calculated
number of
fish of each
age group
returning
9.934
8,836
43, Ml
1,236.953
325,643
20
1,040
47. 298
264. 138
14,294
895
1,325
1,943,927
Calculated
number of
marked flsh
returning
7
81
3,661
115
1,258
29
15,161
Percentage
return Total per-
at various centage
ages return
7.6
.4
19.1
2.0
22.8
40.8
«7.8
'19.6
1213
| 40.8
The incomplete returns from the marked 2-, 3-, 4-, and 5-year seaward migrants
were 7.6, 19.5, 24.3, and 40.8 percent, respectively. Very few 2- and 5-year seaward
migrants were marked, and the returns from those age groups are based on the re-