42 COMMISSION OF CONSERVATION 



accurate conditions as to the composition of the mass. In each catch 

 we find individuals, which may be representative with regard to size 

 and age of the biological group, i.e., the mature herring, to which 

 they belong, but not to the whole stock of herrings. It is necessary, 

 therefore, to take many samples from different schools of fish at dif- 

 ferent places, endeavouring to combine the resulting observations, so 

 as to form, as it were, a complete picture. Moreover, it is in some 

 respects impossible to find any standard by which to judge of the 

 respective quantitative values of the difiFereht groups, even though it 

 may be possible accurately to determine the composition in point of 

 size of each separate group. The investigations of the different 

 biological groups of herring have shown, however, that repeated study 

 from season to season can give a most valuable general idea of the 

 variations and fluctuations in the preponderance of the different ages 

 of year-classes within the different groups, e.g., within the ' fat ' 

 herring and spring herring groups. 



The combined study of the statistics of the fisheries, the catches 

 of the fishermen, and the fluctuation with regard to the year-classes, 

 in the most important groups of herrings, have proved sufficient to 

 demonstrate that the cause of variations in the fisheries is to be found 

 in the great fluctuations in the number of individuals occurring in the 

 larvae and fry developed in the different years — ^fluctuations, that is to 

 say, in the year-classes. 



Present State of Knowledge in Canada 



g A comparison of normal scales of the different types 



Schools may of Canadian herring, shows a marked difference in 

 Mingle j.^(.g ^jj(j manner of growth. Most marked is the 



difference between the Newfoundland herring and the Magdalen 

 Island herring. This circumstance is very important, as both these 

 types occur in the gulf of St. Lawrence, though not in precisely the 

 same areas of that sea. Among the Magdalen Island herrings, a 

 few individuals were found showing a growth very similar to that of 

 the Newfoundland herring, and their scales were so characteristic that 

 they revealed themselves most clearly. In those areas of the sea, 

 where two or more very different types of herrings meet or inter- 

 mingle, it may be possible, therefore, to ascertain the extent of the 

 intermingling between. the different schools, and the areas of distribu- 

 tion and migration of the different types. The gulf of St. Lawrence 

 seems to provide the most excellent conditions for investigations of 

 this kind. 



