VI REPORT TO THE SECRETARY OF COMMERCE 
Growth studies of the cod in Canadian waters indicate that the 
scales do not grow in the same degree as the fish throughout the 
year, but grow relatively more rapidly at one time and relatively less 
rapidly at another. Of 275 cod tagged off Halifax, Nova Scotia, in 
1925, and 3,747 off Shelburne, Nova Scotia, in 1926, more of the 
former lot were recaptured in the following year than during the 
year in which they were tagged, being retaken only along the coast 
and at no great distance, but going more to the southwestward (nearly 
to Liverpool, Nova Scotia) in the second year. The Shelburne cod 
showed very little movement, and that chiefly to the eastward, going 
as far as Liverpool, Nova Scotia, during the season, but reaching 
farther eastward (to Halifax) during the succeeding winter. 
Investigations of the haddock of the Canadian coast reveal that 
the haddock population of the Bay of Fundy, particularly of the 
New Brunswick shore, failed to receive any considerable number of 
young for a series of years, with a resultant decline in the fishery. 
Then the young came in suddenly, and in a year or two the fishery 
greatly increased and has continued at a high level. 
The haddock grows more rapidly in the early years of its life in 
the warm water of Passamaquoddy Bay, New Brunswick, than in the 
cold water on the outer coast of Nova Scotia near Lockeport; but this 
rapid growth falls off in later years in the warm water more than 
in the cold. The rapid growth of the year is limited to the months 
August to October. In 1926 2,540 haddock were tagged near Shel- 
burne, Nova Scotia. They showed very little movement southwest- 
ward along the coast but considerable movement northeastward, as 
far as Halifax and Sable Island Bank—twice as far as the cod tagged 
simultaneously with the haddock. 
The Canadian investigations of the mackerel have shown that it 
spawns in negligible amount in the Bay of Fundy and without suc- 
cess in producing fry, and on the outer coast of Nova Scotia the eggs 
fail to develop into fry. In the Gulf of St. Lawrence, however, 
spawning is extensive and very successful. Late in the summer the fry 
are to be found passing out of the gulf, around Cape Breton Island. 
The eggs have been found to require warm water for successful de- 
velopment. Studies of the mackerel of the Canadian coast reveal 
evidence of differences between those of southwestern Nova Scotia 
and those of the Gulf of St. Lawrence. In 1925 and 1926, in Cana- 
dian waters, 2,382 mackerel were tagged. The returns from those 
tagged at Yarmouth show a movement northeastward to the Gut of 
Canso, northward into the Bay of Fundy, and westward to the coast 
of Maine. Fish tagged at the Magdalen Islands in 1925 showed a 
movement to Prince Edward Island in the same season, and in the 
next year some of them returned to the coast near Halifax and in 
Massachusetts. 
Mackerel tagged in 1925 at various points from Buzzards Bay, 
Mass., to Casco Bay, Me., spread in both directions along the coast 
from the point of tagging but did not migrate far. In the following 
year those recaptured were taken on the whole to the southwest, 
along the coast from where they had been tagged the previous year. 
one tagged on the coast of Maine being taken at Fire Island, N. Y. 
One of the mackerel tagged off Delaware and Maryland in 1926 was 
recaptured several months later near Cape Cod. 
