608 
BULLETIN OF THE BUREAU OF FISHERIES 
Table 4. — Numbers of scallops of all sizes {in 5-millimeter groups ) taken in the various collections 
through 1927 at Pivers Island. {See figs. 23 and 2 If) 
Length, milli- 
meters 
Jan- 
uary 
February 
March 
April 
May 
June 
July 
August 
September 
Oc- 
to- 
ber 
No- 
vem- 
ber 
De- 
cem- 
ber 
17 
1 
19 
5 
20 
4 
18 
4 
19 
3 
25 
8 
23 
2 
22 
6 
20 
11 
9 
23 
to 4.5 . 
313 
256 
290 
40 
27 
13 
4 
4 
1 
4 
3 
22 
71 
243 
174 
290 
387 
142 
to 9 5 
56 
36 
46 
21 
39 
53 
41 
4 
4 
1 
10 
19 
63 
51 
22 
56 
47 
0 to 14 
13 
19 
18 
6 
13 
21 
28 
14 
2 
i 
1 
3 
14 
12 
26 
26 
4 
19 
5 to 19 
5 
19 
8 
2 
12 
18 
13 
27 
7 
6 
3 
6 
3 
2 
8 
0 to 24 
4 
7 
6 
5 
9 
2 
8 
17 
20 
2 
4 
3 
2 
1 
3 
4 
!5 to 29 
6 
7 
8 
10 
14 
5 
2 
6 
17 
13 
1 
1 
2 
1 
JO to 34 
6 
33 
14 
27 
12 
8 
7 
12 
5 
23 
1 
15 to 39 
3 
19 
17 
49 
27 
7 
7 
14 
7 
22 
5 
1 
1 
6 
17 
8 
31 
44 
21 
22 
26 
17 
23 
34 
3 
1 
15 to 49 
3 
7 
10 
20 
26 
15 
17 
16 
20 
21 
19 
25 
3 
1 
1 
>0 to 54 
2 
2 
6 
10 
7 
10 
29 
39 
35 
32 
46 
29 
12 
1 
2 
>5 to 59— 
i 
1 
4 
6 
16 
42 
30 
36 
43 
65 
32 
4 
5 
4 
1 
2 
50 to 64 
1 
1 
1 
2 
3 
6 
32 
19 
50 
35 
52 
45 
37 
32 
13 
7 
35 to 69 
2 
6 
2 
1 
3 
5 
12 
22 
18 
34 
39 
40 
43 
35 
to 74 
32 
22 
18 
12 
5 
1 
1 
1 
2 
3 
3 
5 
8 
8 
11 
35 
65 
!5 to 79 
44 
44 
29 
41 
10 
5 
6 
4 
2 
3 
1 
1 
1 
2 
2 
1 
7 
8 
JO to 84 
18 
26 
31 
31 
9 
5 
4 
6 
10 
3 
2 
3 
1 
2 
2 
35 to 89 
3 
4 
4 
9 
1 
1 
1 
2 
5 
3 
1 
3 
2 
2 
1 
2 
1 
1 
JO to Q4 
1 
1 
1 
1 
1 
1 
Table 5. — Data as to lengths of scallops from certain seasonal collections in 1925, 1926, and 1927. 
Pivers Island, 5-millimeter groupings. {See fig. 25) 
Length, millimeters 
Oct. 21, 
1925 
Oct. 10-18, 
1926 
Oct. 11, 
1927 
Jan. 12, 
1926 
Jan. 17, 
1927 
Jan. 25, 
1928 
May 7, 
1926 
May 4, 
1927 
Aug. 5, 
1925 
Aug. 4-5, 
1926 
Aug. 2, 
1927 
0 to 4 5 _ 
6 
290 
313 
252 
22 
5 to 95 - 
94 
22 
56 
47 
1 
4 
10 
10 to 14 
17 
26 
13 
51 
16 
14 
3 
15 to 19 - - 
11 
3 
5 
19 
4 
27 
20 to 24 _ __ 
3 
1 
4 
6 
9 
17 
25 to 29 
1 
6 
2 
2 
6 
30 to 34 - 
1 
21 
12 
85 to 89 
3 
21 
• 14 
40 to 44 ' 
6 
19 
26 
1 
45 to 49 - - 
3 
10 
16 
50 to 54 _ 
2 
29 
5 
1 
12 
55 to 59 
4 
4 
6 
21 
10 
65 
60 to 64 - - 
5 
0 
32 
1 
8 
i 
2 
20 
41 
35 
65 to 69 - - 
43 
32 
40 
8 
2 
23 
3 
40 
22 
70 to 74 - 
43 
34 
11 
32 
42 
6 
3 
75 to 79 - - 
8 
8 
47 
44 
15 
2 
4 
4 
80 to 84 . 
1 
1 
2 
9 
18 
12 
6 
4 
1 
85 to 89 
3 
2 
2 
90 to 94 
1 
95 to 99 - 
From the data presented in these graphs it is evident that the life of a year 
class is as follows: It originates from summer to winter but principally in the fall, 
grows to sexual maturity so that its members spawn the next fall (summer to winter) 
when a year old. In its second winter it constitutes the market class and, as such, 
is nearly eliminated. Of the few not marketed some survive until the succeeding 
December, but neither these data nor some experiments in which scallops were con- 
fined in a pen give any close indication as to the portion which survive until then, 
or even to summer. 
The length of life attained by the great majority of scallops reaching maturity 
is not over 20 months, but can not be stated with exactitude because of the extended 
spawning and marketing seasons. There is- no evidence of any old age mortality 
before the close of the market season. Of those caught at the end of the season 
(last of April) a very few may be 21 months old, more of them 19 or 20, and a goodly 
proportion about 16 months. Ordinarily, comparatively few survive until the closing 
days of the season. By the last of February the supply is greatly reduced. At that 
