MIGRATIONS OF COD 
15 
RESULTS 
MIGRATIONS OF COD BETWEEN NANTUCKET SHOALS AND NORTH CAROLINA 
EVIDENCE OF MIGRATIONS AS SHOWN BY THE COMMERCIAL FISHERY 
It had long been known that cod appeared in the autumn on the grounds extend- 
ing from Marthas Vineyard, Mass., to Delaware, and even farther south. Since most 
of these fish disappeared in summer, it was logical to conclude that they came from 
the east “somewhere off New England,” but it was not until Smith’s experiments 
(p. 6) that we had definite proof to show that cod from southern New England do 
actually migrate along shore to the Middle Atlantic States region and so form part, 
at least, of the stock of fish on these wintering grounds. 
Each fall the first scattering cod to the westward of Massachusetts are caught 
about the middle of October and apparently are the vanguard of the winter migrants. 
Large bodies of cod follow soon after, for good catches are made beginning late in 
October or early in November and continue until the end of December. After this pe- 
riod a decline in the catch occurs off western Long Isl and and northern New J ersey , which 
is an indication that the fish continue to migrate westward throughout the fall, but 
few arrive after December. Off southern New Jersey there is usually no sudden winter 
decline in the catch of cod per unit of effort, but in this region the fish are scattered 
over a large area, not concentrated on rocky ledges as they are off the northern coast; 
hence local fluctuations in their abundance throughout the winter do not throw so 
much light on their movements. 
Just what proportion of the shore waters west of Nantucket Shoals is inhabited 
by the cod over the winter is not well known. If they are to be found chiefly confined 
to sand, shell, gravel, and rock bottom, as fishing experience suggests, they are 
limited to the area inside the 50-fathom contour and, off Long Island and New 
Jersey, within about 50 miles of the shore. Further off the water deepens rapidly 
and most of the bottom is soft. 
As little fishing is done more than 25 miles from shore to the westward of N an- 
tucket Shoals, it is not possible to follow the migrations of the cod in the offshore parts 
of their range. But the fishery has produced ample evidence that many migrating 
cod travel along a route that lies within about 15 miles of the coast. It is within this 
band that most of the winter’s catch of 3,000,000 to 5,000,000 pounds, taken between 
Rhode Island and Delaware, is obtained. 
Our recent tagging experiments have corroborated the general evidence of a cod 
migration which has been furnished by the commercial fishery, for each year since 
1923 cod tagged on Nantucket Shoals during the summer have been recaptured 
between Marthas Vineyard and Delaware during the following fall, winter, and 
spring, and a few have been retaken as far south as Chesapeake Bay. The results of 
these experiments follow. 
EVIDENCE OF MIGRATIONS AS SHOWN BY TAGGING EXPERIMENTS 
COD TAGGED ON NANTUCKET SHOALS 
Following the cod westward from Nantucket Shoals, the nearest region that 
supports a cod fishery is centered off Rhode Island. As shown in Table 7, many 
tagged Nantucket cod have been retaken in this locality. 
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