MIGRATIONS OF COD 
65 
number of fish above and below these sizes present on the tagging grounds was 
negligible. 
On the cruise made to Nantucket Shoals October 24 to 29, 1928, fewer cod were 
found than at any other time since the beginning of this investigation (p. 44), The 
Albatross II was shifted no less than forty times within the area bounded by Round 
Shoal buoy, Great Rip buoy, and the Chatham grounds in an attempt to find fish, 
but only 304 cod were caught. The lengths of these fish are given in Figure 23, No. 2. 
Because of the small catch of cod and the necessity of combining the several tagging 
grounds on Nantucket Shoals in order to show graphically an adequate sample, only 
a general comparison can be made between the October fish and those caught at 
Round Shoal buoy the previous July. 
The E and the D cod were still present in October, although the gain of about 2 
inches in length registered by each of these groups appears to be somewhat greater 
than we might have expected, judging by previous records, as, for example, the very 
slight gain in length made by the D cod from June to October, 1927. As to the 
status of the 14-inch cod in October, 1928, they may have just attained a size large 
enough to take a baited hook or they may have migrated from elsewhere. Their 
origin is discussed on page 92. Aside from the smallest fish which were caught in 
October, the length frequencies show that very much the same stock of cod was present 
then as in July, and that, therefore, few cod from other regions migrated to the 
tagging grounds on Nantucket Shoals during the interim. 
LENGTHS OF NANTUCKET SHOALS COO IN 1929 
By the summer of 1929 the D cod which were so abundant in July, 1928, and 
which appeared to be well represented in October, 1928, had disappeared from Nan- 
tucket Shoals. (Fig. 23.) It is likely that it was these fish which made up a large 
part of the migrating body which went westward the fall of 1928, and as a result 
many of them were caught by the fishery, and the survivors which returned in the 
spring of 1929 were too scattered to show up in the frequency distribution on the 
tagging grounds between Round Shoal and Rose and Crown buoys. 
The prediction made in 1928 that the E cod might become the dominant body 
in 1929, and possibly in 1930, apparently will not materialize, for in June, 1929, 
they formed about the same proportion of the stock of fish as they did the previous 
October, and in all probability they will pass out of the picture over the winter of 
1929-30. It seems, therefore, that the E cod were a much smaller school than were 
the D fish which were the dominant body of cod on the shoals throughout 1926, 1927, 
and 1928. 
The status of the cod centering around 17 to 19 inches and designated as F fish, 
which were present in June, 1929, is rather uncertain, but, judging from the results 
obtained during the previous years, they were most likely derived from the fish 
around 14 inches long present in October, 1928. Whether these F fish are present 
on Nantucket shoals in 1930 or later depends partly on how abundant and wide- 
spread they are and on how many of them migrate into the Rhode Island-North 
Carolina region the fall of 1929. As at least one school of cod is present on the 
shoals each year, it would seem that the F fish would be the most likely inhabitants 
in 1930. 
On the Great Rip tagging grounds only 80 cod were caught in June, 1929, and 
are not shown graphically. It was found, however, that 21 of these, or about one- 
fourth the total, were 18 to 20 inches long, or in the category of the F Round Shoal- 
