330 THE SEAS 



The fishermen's catches tell us at any rate that when the 

 spawning season arrives the herring congregate in the coastal 

 water. It is probable that after the completion of spawning 

 they move out from the coasts into deeper water, as is 

 testified by the fact that they can be captured in large 

 numbers in the trawls in the deep waters off the Bristol 

 Channel, the Smalls Grounds. 



We have mentioned previously (page 280) the former 

 belief that after spawning all the herring retired to the 

 Arctic Ocean to recuperate, whence they once more moved 

 down along our coasts in the following year to spawn. 

 This is generally now considered to be an incorrect view, 

 and it is thought that when not spawning the herring con- 

 gregate into the deeper off-shore water. This has led to 

 the opinion that there are definite " races " of herring 

 which keep more or less in their own regions. Thus there 

 are the Baltic herring, a race of small sized fish ; the Channel 

 herring from the English Channel ; the Iceland herring, 

 and others. It has indeed been found that the herring 

 coming from widely separated localities exhibit certain 

 differences in their structure. Notably is this the case in 

 the number of vertebrae the fish possess in their backbones. 

 It is generally the case that the herring from the coastal 

 areas, where the water is of low salinity, have fewer 

 vertebrae on an average than those from more saline ocean 

 waters. Thus, the Baltic herring have an average of 

 between 55 and 56 vertebrae, those of the western end of 

 the English Channel 56 to 57, and the Iceland herring 

 between 57 and 58. By counting the vertebrae in large 

 numbers of fish from different localities and studying the 

 age of the fish from their scales, it appears probable that it 

 may eventually be possible to trace roughly the movements 

 of the various herring races. 



When counting the herring vertebrae it is usual to bring 



