Fishery bulletin of the Fish and Wildlife Service - NOAA

FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 287
EXPERIMENTS IN 1932
Four marking experiments were conducted (tables 39-42). The fish marked in
the first experiment were captured on May 27 and 28; those in the second experiment
on May 30, 31, June 3, and 4; the fish for the third experiment on June 6, 7, 8, and
9; and the fish in the fourth experiment on June 11, 12, and 22. The experiments
were planned, in part, to determine whether or not a differential mortality in the
ocean existed between fish marked b/ the amputation of the adipose and one ventral
fin and fish marked by the amputation of the adipose and one pectoral fin, and to
determine if a correlation existed between the time of occurrence of fish in the migration
period and the time of their occurrence in the runs on their return as adults.
In the first experiment (table 39), 15,000 seaward migrants were marked by
amputation of the adipose and right ventral fins, 341 fish were recovered, and a calculated
total of 2,957 marked fish returned (19.7 percent). The return from the 3-,
4-, and 5-year marked seaward migrants was 19.1, 20.5, and 3.0 percent, respectively.
1
2
3
4
5
1
2
3
4
5
Ageoi
seaward
migrants
marked
Total
Age of
seaward
migrants
marked
Totfll
Calculated
number of
each age
marked
0 275
8,593
132
16,000
Calculated
number of
each age
marked
6,029
8,824
147
16,000
TABLE 39.—Data for the first 1938 marking experiment
Age of fish
returning
from 1932
migration
4,
( 4j
1 и
1 63
4i
61
6:
7»
5<
64
81
6,
7i
81
Calculated
number of
each age
group
examined
837
12, 225
8,625
148
1,041
88,164
113
2,077
6б,6бв
67
60
171
46
203, 593
Number of
marked
fish of
each age
group
found
2
116
301
11
139
2
1
341
Percentage
occurrence
of marked
fish in fish
examined
0.192
.132
.886
.630
.245
3.509
2.174
Calculated
number of
flshof
each age
group
returning
2 811
53,258
41, 299
790
6,771
632,884
1,281
20, 626
494, 716
664
418
1, 778
207
1, 662, 491
Calculated
number of
marked
fish
returning
13
835
11
109
1,212
TABLE 40.—Data for the second 1938 marking experiment
Age of fish
returning
from 1932
migration
4,
f 4i
J 5,
1 6î
Г 4i
1 5i
1
в >
1 7«
5t
6i
74
84
6j
7,
8l
Calculated
number of
each age
group
examined
837
12, 225
5,525
148
1,041
88,164
26, 912
113
2,077
56, 666
9,551
57
60
171
46
203, 593
Number of
marked
fish of
each ago
group
found
97
49
1
91
46
1 1
286
Percentage
occurrence
of marked
fish in fish
0.110
.182
.048
.161
.482
.585
2.174
Calculated
number of
fish of
each age
group
returning
2,811
63, 258
41, 299
790
6,771
632, 884
304, 079
1,281
20, 626
494, 716
100,909
664
418
1,778
207
1,662 491
23
4
2,967
Calculated
number of
marked
fish
returning
696
653
10
796
486
10 4
2,555
Percentage
return at
various
ages
0.2
13.3
.2
1.3
14.1
.3
3.0
Percentage
return at
various
ages
11.6
9.2
.1
9.0
6.5
6.8
3.0
Total
percentage
return
i L1
1 19.1
J
1 20.6
í
I
1 3.0
Total
percentage
return
20.7
14.6
9.8