MIGRATIONS OF COD 
41 
which no Nan tucket- tagged cod have been reported, the catch of cod landed in 
American ports during 1924 amounted to 5,490,000 pounds. 
The foregoing list of recaptures shows that — 
1. No seasonal migration of cod took place from Nantucket Shoals to any of 
these various localities, because the few miscellaneous recaptures were taken during 
every month of the year except January. 
2. On an average only 1 out of 800 cod marked on Nantucket Shoals was 
reported recaptured to the north and east of Cape Cod. Even allowing for the 
tag-scarred fish, which were not reported because they were not recognized by the 
fishermen, the percentage of Nantucket cod which stray to the north and east is 
very small according to the tag records. 
3. According to the limited amount of tagging done on the Chatham grounds, 
this region, too, contributes only a small part of its cod to the northward and eastward. 
4. It is evident that most of those fish which do migrate north and east of Nan- 
tucket Shoals, Chatham, or South Channel follow a route along the shore from 
Chatham to Maine. The only offshore records we have are 8 for Georges Bank and 
1 for La Have. It would be interesting to know the route of the latter. The 
recaptures of Nantucket fish at various points along the coast of northern New 
England suggest that the La Have fish followed the shore route rather than that it 
crossed Georges and the deep channel that separates the latter from the Scotian Banks. 
The 8 Georges Bank recaptures of Nantucket-tagged cod just mentioned are so 
few that they constitute further evidence that most of those cod which do migrate 
north from the shoals select the shore rather than the offshore route, and they give 
some indication as to why so few recaptures in the face of intensive fishing were 
reported from the South Channel region, namely, that relatively few cod migrate 
eastward from Nantucket Shoals to the offshore grounds. 
The many unknown factors having to do with the migrations and behavior of the 
cod, together with the element of chance which always plays a large part in our 
fisheries, make it unwise to give too much credence to these numerical data. For 
example, it is probable that the loss of tags tends to reduce the number of returns 
from northern localities more than from the local or the western migration recaptures 
of Nantucket cod because the time intervals in the former average somewhat longer 
than for the latter. But even so, we are justified in saying that on the basis of tag 
returns over a period of six years only a relatively small proportion of the stock of 
Nantucket-Chatham cod move to regions east or north of the Chatham grounds and 
South Channel each year. 
COD WHICH GAVE NO EVIDENCE OF MIGRATING 
In all previous cod-tagging experiments it has been found that a large part of 
the fish marked remained for a period of months or years in the immediate locality 
where they were released. Most of these fish were taken within the first few months, 
before enough time had elapsed for them to lose their tags, but of those which retained 
their tags some were retaken as much as a year or more later. Thus many of the 
cod tagged off the mouth of Buzzards Bay during the winter by Smith (1902) remained 
near by until spring, when they migrated eastward to Nantucket Shoals, which is 
the nearest year-round cod ground. And in European waters many of the cod 
tagged in the North Sea off the Faroes and around Norway and Iceland were recap- 
tured months later without having shown a migration of more than a few m iles. 
