MIGRATIONS OF COD 
37 
Table 22. — The reported number of Nantucket Shoals tapped cod taken in South Channel from 1928 
to 1928 by fishing vessels operating out of Boston, Gloucester, and Portland together with the catch 
of cod for each month 
Number of cod taken by the New England fleet and, in parentheses, the oateh of Nan 
tucket Shoals tagged cod 
Month 
1923 
1924 
1925 
1926 
1927 
1928 
January.. 
> 17, 803 
27, 000 
34, 162 
50, 920 
52, 754 
62, 115 
February. 
i 23, 866 
37, 472 
49, 673 
40, 675 
42, 488 
63, 655 
March 
i 26, 658 
32, 594 
28, 207 
60, 429 
73, 992 
62, 410 
April 
23, 686 
42, 668 
40, 331 
39, 353 
87, 988 
59, 249 
May 
36, 333 
31,673 
31, 286 
33, 293 
(1) 
56,528 
32, 613 
June 
90,415 
70, 905 
(1) 
85, 449 
(2) 
83, 665 
(1) 
67, 693 
67, 345 
July 
169, 367 
(2) 
88, 961 
125, 674 
(2) 
109, 783 
(3) 
96, 940 
95, 599 
(1) 
August. . 
164, 197 
(1) 
147, 454 
(1) 
155, 831 
(7) 
124, 287 
(2) 
202, 296 
(1) 
„ 247, 083 
(1' 
September 
112,014 
(1) 
169, 542 
(1) 
168, 211 
(2) 
91, 573 
(1) 
210. 060 
(1) 
158, 453 
October 
91,613 
(1) 
140, 069 
(1) 
70, 818 
(3) 
135, 190 
156, 774 
(3) 
131,410 
November . 
58, 745 
(1) 
48, 569 
52, 968 
75, 579 
107, 983 
106, 181 
(1) 
December _. ... 
28, 970 
29, 645 
19, 314 
40, 524 
67, 853 
76, 222 
Total 
843, 667 
(6) 
866, 552 
(4) 
861, 924 
(16) 
885, 271 
(8) 
1, 223, 349 
(5) 
1, 162, 335 
(3) 
1 The first cod of this investigation were marked in April, 1923, so that statistics prior to then can have no relation with the 
tag returns. 
The available statistics of the catch of cod taken in the Chatham-South Channel 
region are not sufficiently complete for the preceding table to give more than a general 
idea of the relationship between the number of cod caught and the number of tagged 
cod retaken. For example, the records show no catch of cod on the Chatham grounds 
for the summer of 1923 or for June, 1927, yet a total of 8 tagged fish were taken there 
during these periods. (Table 21.) This discrepancy is evidently due to the fact 
that the Chatham grounds and South Channel merge one into the other, so that 
boats which fish in this general region might describe their fish as from either place. 
Yet in spite of this confusion that may obtain from time to time, it is probable that 
fishermen as a rule do distinguish between the two localities and state their catch 
correctly as from one or the other. 
Only 42 Nantucket Shoals tagged cod were reported among about 6,000,000 cod 
caught in South Channel from 1923 to 1928, or 1 for each 142,000, whereas 62 were 
reported from the Chatham grounds among about 167,000 taken there, or 1 out of 
each 2,700. Direct computation would indicate a concentration of Nantucket 
tagged cod on the Chatham grounds over fifty times as great as in South Channel. 
This figure is undoubtedly too high because more tags were overlooked or lost in the 
channel where otter trawling is the prevailing method of fishing than off Chatham 
where much line trawling is done. But in spite 6f this, the small yield of tagged 
cod in the South Channel region affords rather good evidence that comparatively 
few Nantucket cod move eastward to the offshore banks. 
A comparison of the catches of cod made in the Chatham-South Channel region 
during the summer and winter seasons of the years from 1923 to 1928 shows a sur- 
prising result. On the Chatham grounds only 3 tagged fish were reported among a 
catch of about 131,000 cod taken from December to May (about 78 per cent of the 
total catch), whereas from June to November 59 tagged Nantucket cod were reported 
among a catch of about 37,000 fish (22 per cent of the total catch). In South Channel 
only 1 tagged cod was reported from December to May among about 1,500,000, while 
41 tagged fish were recorded from nearly 4,500,000 cod caught from June to November. 
This contrast in the numbers of summer and winter recaptures reported from the 
Chatham-South Channel region was not brought about by chance, for the experiment 
