4 
The migrations of the herring have been considered among the wonders of 
the deep. Little speculation has been reported about the Pacific species, but 
its habits are much like those of the Atlantic species, about which so many 
theories have been propounded. There is nothing to indicate that the move- 
ments of the Pacific herring are any more mysterious than those of any other 
active fish, but since they move about in such large schools their. presence or 
absence in any one location is much more readily observed. I cannot find any 
reason for thinking that any herring that are found in the strait of Georgia have 
ever been away from the strait or the various channels adjoining, and it may 
readily be that the radius of activity is limited to comparatively few miles. 
Their movements seem to be due largely to the necessity of following up the food 
supply. The main basis of that supply is provided by copepods. Among hun- 
dreds of stomachs examined I do not remember finding a single one in which 
the contents were recognizable where there were not copepods, as eggs, larve 
or adults, no matter what else was found. The necessity for a supply of these 
copepods is, therefore, constant. I have never counted the number present 
in the stomach of a mature herring, but in a young herring 6.6 cm. long, over 
3,000 copepods were present. As digestion takes place very rapidly that would 
probably by no means represent the number taken in a whole day. When this 
is true for a herring six months old, how many must be needed for a mature fish, 
and then how many for a school of fish having several! million individuals? 
When it is tmpossible to conceive of such a number is it any wonder that there 
is often a sudden migration of the fish to catch up with the food supply? Even 
if the copepods are numerous they do not remain indefinitely in any one locality. 
They are affected by temperature, intensity of light, by currents and probably 
by the degree of salinity and many other conditions, and in the case of some at 
least of these conditions, the change will affect the copepods in mass. In these 
wanderings the herrings must follow. A school of herring can be observed only 
when these herring are feeding near the surface of the water. They have not 
far to go from the shallow water near shore to get into water deep enough to 
cover up all evidence of their presence. 
It is true that by going back to the copepods the matter of migration is 
simply removed one step further. Another step is made by passing on from 
copepods to diatoms on which they feed. This places a limit as far as organisms 
are concerned, unless bacteria have something to do with preparing the food for 
the diatoms. The processes preceding must be left to the physiologist; the 
chemist and the physicist. This is not all that is to be said in the matter how- 
ever. In February and March, when copepods and diatoms are scarcer than 
usual in the surface waters of the strait, the herring find it necessary to supple- 
ment the copepod diet. They come into shallow water at times and feed on the 
nauplius and cypris larve of the barnacles and for days at a time they remain 
in the barnacle zone. This is most noticeable about spawning time, hence, 
_although it is usually stated that they come into the shallow water to spawn, it is 
possible that the reason of their presence is entirely or largely due to the food supply, 
the spawning in shallow water being merely incidental. Mollusc eggs, decapod 
and other crustacean larve, ascidian larve and rotifers are also eaten, but in 
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