170 ADULT HEEKINGS 



(2) Dogger Bank Herrings 



The Dogger herrings caught in the trawls therefore seem to 

 have consisted in all three years largely of fish belonging to the 

 (a) 1909 and (b) 1910 broods, and they included in all four years 

 a considerable number, and in 1912 no less than 67 per cent, of 

 fish over six years old. 



So far there is here no conclusive evidence for or against the 

 application of the Norwegian theory to British herrings. But 

 it is apparent that inquiries along these lines might eventually 

 enable us to decide whether particular ' broods ' of herring 

 survive in some years in abnormal quantities, and whether 

 these broods appear to preponderate in the catches of subse- 

 quent years. They might further show lohy some years were 

 ' good ' for herring and others ' bad '. To arrive at the cause 

 it would, of course, be necessary to know whether the brood in 

 question had been hatched in the spring or in the autumn, and 

 to discover the conditions, such as the amount of food and the 

 water temperature on the bottom of the spawning grounds 

 which prevailed during the babyhood of the fish. 



Mr. Storrow and Mrs. Cowan continued their inquiry right 

 through the war with the cordial co-operation of the fishermen 

 at North Shields. They have not, it is true, hitherto been able 

 to indicate whether, and if so why, the parent herring is more 

 or less likely to produce a large and healthy family in one year 

 than in another. They have, therefore, not as yet added very 

 much to our chance of solving the all-important problem of 

 fluctuations in the herring-stock on the lines laid down by the 

 great Norwegian naturalists. But they have not worked in 

 vain. 



In 1919 Mr. Storrow showed good reason for beheving that 

 some of the herrings which spawn during the spring in the Firth 

 of Forth were supplied from the shoals which feed off the 

 Northumberland coast during the summer. In February 1920 

 he examined 54 herrings ; all of these were over 7-8 inches long 



