600 U. S. BUREAU OF FISHERIES 
REVIEW OF FISHERY INVESTIGATIONS CONDUCTED BY THE BUREAU 
OF FISHERIES 
NORTH ATLANTIC FISHERIES 
GENERAL REVIEW 
By Dr. H. B. BIGELOw 
I didn’t come here with any set speech, so shall say only a word of remi- 
niscence about the North Atlantic investigations. 
The life histories of the fish that support the great North Atlantic fisheries 
have been slighted in American waters—cod, haddock, pollcck, mackerel, her- 
ring—and when it became possible to undertake such studies a few years ago 
the two problems that seemed to promise the most fertile field were the lives of 
the cod and mackerel. - 
The cod has been the backbone of the North Atlantic fisheries on this side 
of the Atlantic, and a good deal of attention has been paid to the life history 
of the cod on the other side of the Atlantic, so the: basic facts of the cod’s life 
history are well understood. Nothing, however, was known about the migra- 
tions of the codfish in American waters nor about what conditions favored 
years of high production (and so good fishing) or what hindered years of high 
production ; and until some light was thrown on these questions it was obvious 
that the bureau never could outline any rational means of conservation if 
the fishery should show signs of depletion or tell the fishing interests how 
they could increase their catches if there was opportunity and if the fish 
market would take them. } 
The simplest problem to attack in the case of the cod was migration; and 
so, in 1923, the bureau started tagging codfish. Fortunately, the codfish proved 
to be a very favorable fish to tag. We have some codfish that have been tagged 
and recaptured twice, on which the tags look perfectly all right—the cod has 
been perfectly fit and happy and his rate of growth hasn’t been set back. 
Consequently we have every reason to think that the cod returns are sig- 
nificant, even though many of the fish lose their tags. 
Tagging has been carried on from 1923 up to date. During the first years 
the bureau was limited in the field that could be covered by the iack of a 
seaworthy ship. Those of you who have worked at sea know that on the 
high seas, often in winter, you must have a ship that is seaworthy if you want 
to do the job. Now the bureau has become possessed of a ship that is sea- 
worthy ; she can go anywhere; so this last year the bureau was able to spread 
its tagging operations to Georges Bank, and in the future there is no reason 
why such work can not be carried out anywhere on the offshore banks. 
While the cod tagging has been going on, haddock and pollock have been 
tagged too, and data have gradually accumulated to show the migrations of 
these species as well. Mr. Schroeder has worked up the report on the migra- 
tions of the codfish which he will present to you shortly. As to the factors 
that control production, ete., a start was made two winters ago by the Fish 
Hawk in Massachusetts Bay. Very satisfying things came out as to the invol- 
untary drifts of the eggs and larve. We knew previously from European 
experience that cod eggs and larvee, like any other buoyant eggs, drift where 
the water takes them. And it does not follow because a lot of larve are 
found in one place that they were spawned there. Doctor Fish will tell you 
about this one actual start that has been made in the Massachusetts Bay 
region on that problem. Mr. Sette can tell you about the mackerel. 
I might add that all the work carried on at sea has been accompanied con- 
stantly by an oceanographic program, yielding records of the temperature of 
the water, of the salinity of the water, and of the nature and abundance of the 
plankton, data which, when tied up with the production of eggs, may tell us 
what factors favor high years of production and what things go against it. 
We begin to suspect that it is not so much the physical character of the water. 
In fact, Doctor Leim’s experiments on cod eggs show that the cod egg is almost 
foolproof. You can do almost anything to it and still it will hatch successfully. 
The great loss apparently comes after that, and we begin to suspect that it is 
the predatory members of the plankton that are chiefly to blame, combined 
with the scarcity of food for the larval fishes. 

EE 
