MIGRATIONS OF COO 
73 
to 60° F.) in the late summer, the degree depending on whether it is a cold or a warm 
year. The minimum temperature in late winter probably is somewhere between 2° 
and 3° C. (35.6° to 37.4° F.), for on February 24, 1929, we found it to be 1.4° C. 
(34.5° F.) on the surface and 2.6° C. (36.7° F.) on the bottom in 1 1 fathoms olf Round 
Shoal buoy where so many of our cod were tagged on the shoals from April to October. 
We naturally examine with interest the temperatures west of longitude 70° W., 
particularly those of late summer, in the hope of finding some explanation as to why 
cod go there in the fall to spend the winter but leave again in the spring. The tem- 
peratures given in Table 30 were selected to cover (a) the period when the first cod 
migrate westward from Nantucket Shoals, ( b ) the period of maximum migration, (c) 
midwinter, (d) the period in the spring when the last of the cod are believed to leave 
their southern wintering grounds, and (e) the period in summer when maximum 
temperatures obtain and when cod have seldom been found west of Rhode Island. 
The temperatures which are listed were taken on or within a few meters of the 
bottom and each represents a different station. Those recorded prior to 1926 were 
taken from Bigelow (1915, 1917, 1922, 1927) and those after were obtained by the 
Halcyon and the Albatross II on tagging and hydrographic cruises. 
Table 30. — Bottom water temperatures from west of Nantucket Shoals 
[All positions listed are true positions. The letters before the station numbers are to be interpreted as follows: A = Albatross II; 
Q = Grampus; and H = IIalcyon] 
Refer- 
ence 
No. 
Station 
Date 
Position 
Locality 
Depth 
Temperature 
Meters 
Fath- 
oms 
° C. 
° F. 
Off Marthas Vineyard and Rhode Island 
1 
A 20261 
May 25, 1927 
41 
06 N. 
10 miles S. by E. from No Mans Land 
30 
16 
7.7 
45.8 
70 
47 W. 
2 
G 10357 
July 26,1916 
41 
11 N. 
5 miles SE. from No Mans Land ... ._ 
25 
13 
14.3 
57. 7 
70 
44 W. 
3 
G 10356 
40 
57 N. 
28 miles SE. from No Mans Land. ... ... 
30 
16 
12. 1 
53.8 
70 
18 W. 
4 
G 10355 
July 25, 1916 
40 
43 N. 
57 miles SE. from No Mans Land 
30 
16 
11.0 
51. 8 
69 
53 W. 
5 
G 10354 
40 
26 N. 
80 miles SE. from No Mans Land 
70 
38 
6.1 
43.0 
69 
24 W. 
6 
Aug. 2, 1920 
1 mile NW. from Gav Head, Marthas Vineyard 
13 
7 
7 
2!4 miles SW. from Gay Head, Marthas Vineyard 
27 
15 
ifi n 
8 
G 10112 
Aug. 22,1913 
40 
17 N. 
57 miles S. by W. from No Mans Land 
110 
60 
15.4 
59.7 
70 
57 W. 
9 
G 10263 
Aug. 27,1914 
41 
12 N. 
6 miles SW. from No Mans Land 
17 
9 
13.3 
55. 9 
70 
57 W. 
10 
G 10258 
Aug. 25, 1914 
41 
03 N. 
13 miles S. from No Mans Land 
30 
16 
12. 1 
53.8 
70 
51 "W. 
11 
G 10259 
40 
34 N. 
41 miles S. from No Mans Land .. .. .. 
55 
30 
9.7 
49.5 
70 
46 W. 
12 
G 10262 
Aug. 26,1914 
40 
02 N. 
80 miles S from east end of Marthas Vineyard 
180 
98 
10.3 
50. 5 
70 
28 W. 
13 
G 10260 
40 
03 N. 
80 miles S. from west end of Marthas Vineyard 
140 
76 
11.4 
52.2 
70 
41 IV. 
14 
G 10331 
Oct. 22,1915 
41 
19 N. 
4 miles E. from west end of Marthas Vineyard 
30 
16 
14.5 
58.0 
70 
55 W. 
15 
G 10332 
40 
51 N. 
24 miles S. by W. from No Mans Land 
50 
28 
13.1 
55.1 
70 
55 W. 
10 
G 10333 
40 
26 N. 
48 miles S. by W. from No Mans Land 
80 
44 
11.9 
53.4 
70 
56 W. 
17 
Oct. 28, 1925 
41 
12 N. 
4 miles S. from No Mans Land 
18 
10 
12. 1 
53.8 
70 
51 W. 
18 
Oct. 27, 1925 
41 
18 N. 
8 miles E . from west end of Marthas Vineyard 
33 
18 
11. 7 
53.0 
71 
00 W. 
19 
do 
41 
11 N. 
6 miles E. from Block Island. _ .. 
22 
12 
11. 7 
53.0 
71 
28 W. 
20 
G 10405 
Nov. 10, 1918 
41 
17 N. 
10 miles E. from west end of Marthas Vineyard 
30 
IS 
12.5 
54. 4 
71 
03 W. 
21 
G 10406 
Nov. 11, 1916 
40 
37 N. 
34 miles S. from Block Island 
60 
32 
10. 0 
50. 0 
71 
19 W. 
22 
G 10407 
do 
40 
03 N. 
67 miles S. by W. from Block Island 
90 
49 
7. 7 
45. S 
71 
43 W. 
23 
G 1C403 
do., 
39 
52 N. 
SO miles S, by W. from Block Island...... 
ISO 
9S 
10.3 
£0.5 
71 
47 W. 
