MIGRATIONS OP COD 
55 
The stock of cod 6 to 12 miles east-southeast (fig. 18, No. 1) differed in their 
length frequencies from those living in the immediate vicinity of the buoy, for we 
found (1) that the 18 to 20 inch fish, C, so dominant at the buoy were barely discern- 
ible to the east-southeast, while (2) the 25 to 28 inch fish, B, weakly represented by 
26-incb fish at the buoy, were the dominant group to the east-southeast. A good 
proportion of larger fish above 28 inches also were present easjt-southeast of the buoy; 
and, though the group was not well enough defined to indicate its origin, it is not 
improbable that many of them were from the A group that were traced to this locality 
in 1924. The 25 to 28 inch cod, B, were apparently the same school which inhabited 
the east-southeast grounds in July, 1924 (fig. 15, No. 2), when they were 23 to 26 
inches long. This, together with the fact that there was a marked decrease in the 
proportion of B cod present on the Round Shoal buoy grounds in June, 1925, as com- 
pared with May, indicated that this school moved eastward between early May and 
early June to join the fish already living on the grounds 6 to 12 miles east-southeast. 
This same sort of migration occurred in 1924, when our A fish were traced to these 
grounds. The results obtained in August, which follow, likewise favor this theory. 
Figure 18. — No. 1 = length-frequency distribution of 517 cod caught 6 to 12 miles ESE. of Round Shoal buoy June 7-12, 
1925. No. 2=lengt.h-frequency distribution of 1,038 cod caught at Great Rip buoy August 21-25, 1925 
Fishing was restricted to the grounds near Round Shoal buoy and Great Rip buoy 
on our next cruise to Nantucket Shoals, August 21-25, 1925. 
The C school, which predominated at Round Shoal buoy in June, 1925, with a 
peak at 19 inches, was still the dominant group in August, but the peak had moved 
to 20 inches (fig. 17, No. 3), doubtlessly, because the fish increased that much in 
length. The B school which was on the wane from May to June, 1925, formed a still 
smaller part of the stock of fish near Round Shoal buoy by August. The sharp peak 
at 26 inches in June, 1925 (fig. 17, No. 2), had flattened and centered around 27 to 28 
inches by August, due partly to increased growth and partly to the larger sample of 
fish obtained the latter month. It is apparent from the results of our fishing in May, 
June, and August that the B cod were leaving the Round Shoal buoy grounds. As it 
was during this time that an emigration of tagged cod occurred from Nantucket Shoals 
to the Chatham-South Channel region, and as B cod were dominant east-southeast 
of the buo} 7 in June, 1925, and were still well represented at Great Rip buoy in August, 
1925, it is apparent that they moved from Round Shoal buoy in an east-to-south 
