ADULT HERRINGS 173 



the trade of herring-shoals which spawned in spring all the way 

 from the north-west of Shetland to the Butt of Lewis. It may 

 therefore be necessary to modify the theory that ' Shetland ' 

 herrings are autumn spawners (p. 163). 



Age 



Mr. Storrow has long ago convinced himself that it is difficult 

 to distinguish spring spawned herrings from the autumn broods. 

 He never attempts to decide that a particular fish was hatched 

 in a particular year, and contents himself with recording the 

 number of rings on the scales. In the samples from the summer 

 catches in 1919 and 1920 he found a very large proportion of 

 ' three-ringers ' — 52 per cent., for instance, at Peterhead, 69 per 

 cent, at North Shields, 51 per cent, at Scarborough, and 37 per 

 cent, at Stornoway. Some of these three-ringers, he tells us, 

 were ' spring ' fish — and these were three and a half years old 

 when they were caught ; others were ' autumn ' fish and four 

 years old. In fact, of the three-ringed herrings caught from 

 Wick to Scarborough, some w^ere batched in the autumn of 1915, 

 others in the spring of 1916. It will be interesting to see whether 

 a large proportion of the north-east coast herrings in 1921 are 

 four-ringers. 



Maturity ^ 



Storrow^'s discoveries as to maturity are most important. 

 Some of the spawners, both in spring and autumn, from Storno- 

 way, Peterhead, Scarborough, and Yarmouth were ' two- 

 ringers' only, that is to say, fish which were either two and a half 

 or three years old. On the other hand, he has found maiden fish 

 which had not yet started spawning as follows : 



From Stomoway and Lerwick . . . 6-ringers 



From Wick, Peterhead, and North Shields . 5 -ringers and 4 -ringers. 



There is nothing surprising in this. As Storrow points out, 

 cock-salmon may spawn even before they go to sea for the first 

 time, while other salmon may spend four or five years at sea 

 before returning to fresh water to breed. But he has made it 

 clear that individual sea animals of the same species, unlike 

 land animals, do not all become capable of reproducing their 

 kind at even approximately the same age. And this is another 

 good illustration of the wisdom of Hjort when he warns us against 

 applying the methods of landsmen to the ' vital statistics ' of 

 the sea. 



Why do some herrings contract infant marriages, while 



1 Dahl has found that ' herrings spawn from the third to the fourteenth year, 

 the majority between four and eight years old ' {Depths of Ocean, p. 766). 



