29 



than once, but their first year growth is also great in range and 

 gives support to the above possible origin of spring and autumn 

 spaAvning shoals. Below are given particulars of the first year 

 growth of the older fish found in spawaiing shoals in the vicinity 

 of Stornoway : — 



NUMBERS AT CENTIMETRES. 

 3 G 7 8 9 10 11 12 13 14 If) Total. 



The maturity data, Table II., show that practically the whole 

 of the above fish may be dealt with as spaAvning fish or fish about 

 to spa^Ti. From the above particulars it is evident they originate 

 from summer feeding shoals which have been shown to consist 

 of young born in both spring and autumn, and it is also evident 

 that the first year growth gives no reason for concluding that 

 spring spaA\Tiers give rise to j^oung which, without exception, 

 will become spring spa\vners, or that autumn spavvners give young 

 which will all become autumn spa^\^lers. The facts point to what 

 has been stated, and that is that spring spawners may come from 

 young fish born either in spring or in autumn, and autumn spawners 

 may originate in the same way. 



Further data similar to that given above, and supporting the 

 conclusion here expressed, will be found in the growth table for 

 herrings from the Shetlands. 



This relationship between spring and autumn spamiing herrings 

 is opposed to Heincke's* conclusions. But Matthewsf was unable 

 to find any racial difference between spring and autumn spawners 

 from Scottish waters, and the small differences which he noted 

 would probably have disappeared had the data been examined 



* Die Naturgeschiclite des Herings, 1898. 



t Report as to \ariety among tlie Herrings of the Scott jsli Coasts. Rcpts. Eish Bd. 

 Scot., 4th and 5th. 



