334 



Part III. — Twenty-fourth Annual Report 



With regard to the spent herrings, it may be noted that 13 females 

 and 8 males belonged to the first series, and 24 females and 35 males to 

 the second series. The two large females were spent and another at 

 288mm. The grouping of the spent fish in '5cm. is as follows : — 



21-5 22 -5 23 '5 24 "5 25 "5 26 "5 27 5 2S 5 29 "5 30 '5 31 "5 32 5 



Males, 1 - 1 2 5 4 5 4 8 4 ] 2 - - 1 ------ 1 1 



Females ,- - -521 7 13 71331 - -- -- -- -- - 



1 -1775 12 17 15 5451-1------11 



8. Conclusions. 



It is evident from the above account that the herring grows slowly, 

 and that those authors who supposed that it might reach the mature 

 condition in a year or eighteen months were very wide of the mark. 



At the' end of the year in which it was born, that is to say, in 

 December, the spring herring rarely exceeds 50mm. (2 inches), and the 

 great majority are much smaller; at the same period, the autumn 

 herring may be as small as 14mm. (a little over | an inch), and is rarely 

 over If inches, or 35mm. This difference between the spring and 

 autumn herring, it may be said, persists throughout. There is nothing 

 to indicate that the rate of growth is greater in one than in the other, 

 an interval of about l*5cm.-2cm., or a little more, separating the mean 

 sizes of the two classes at the same date. This is what might be 

 expected, since an interval of five or six months intervenes between the 

 spawning periods, and the difference in size between the spring and 

 autumn herrings thus represents about half the amount of the growth 

 in a year. 



While both autumn and spring herrings are included in the collec- 

 tions witb which T have dealt in this paper, those of the latter are the 

 most complete ; and I have set forth on the accompanying table the 

 particulars regarding a number of the collections in order to show, in 

 collective fashion, the rate of growth and the age at different sizes. 

 Though these collections belong to different years and to various 

 localities (but all on the east coast of Scotland), it will be seen that 

 there is a very considerable uniformity of results. 



The monthly rate and the annual rate of growth, it may be said, are 

 calculated from a larger number of decimals than the rate per day, and 

 the age is computed from the middle of March. It will be observed 

 that the growth in the summer months is much more rapid than in the 

 colder part of the year ; and the mean annual rate of growth in the 

 four best cases, where the period is long and the numbers of herrings 

 considerable, is 43'4mm., or about If inches. If the rate between 

 January and May is included (49 6) the mean rate is 44* 6mm. 



[Table. 



