336 



Peart TIL — Twenty-fourth Annual Report 



Growth in length, however, as with most fishes, is somewhat more 

 rapid in the early stages, and diminishes with age, at first very slowly, 

 and then on the occurrence of sexual maturity with great and marked 

 rapidity. 



The following gives the main features of the growth of the herring, 

 according to this investigation : — 



Approximate Age. 



Length. 



Increase in Length 

 from Previous Year. 





arm. 



Inches. 



Mm. 



Inches. 



1 Year, 



60-5 



2f 









113 





52 



2& 



3 „ 



159 





47 



II 



4 „....'. . 



200 





41 



If 



5 „ 



238 



n 



38 



H 



6 



257 



m 



19 



1 



The herring, both male and female, appears to attain the mature 

 condition, and to reproduce for the first time, when it is five years of 



age. 



If the same rate of growth as is indicated above between the fifth and 

 sixth years be assumed to continue during the next few years, the 

 approximate average sizes of older herrings would be as follows : — 7 

 years, 276mm. (10^ inches); 8 years, 295mm. (11 j inches); 9 years, 

 314mm. ( 1 2^ inches) ; 10 years, 333mm. (13^ inches). It is certain, 

 however, that the growth in the later series of larger herrings is not 

 nearly so rapid as this, and herrings over 12 inches are probably more 

 than ten years old. The larger herrings of 13 to 15 inches, such as are 

 referred to on a former page, must be very old ; the latter probably 

 from fifteen to twenty years. 



It may be of interest now to compare briefly the results as stated 

 above and those obtained by Jenkins and Masterman. The research of 

 the former, as previously mentioned, was made on the otoliths of spring 

 herrings of the Baltic, and the precise age could not, therefore, be deter- 

 mined with certainty, not within several months. The research of 

 Masterman was on both spring and autumn herrings at St. Andrews, 

 but was confined to specimens taken in tow-nets — to larval and post- 

 larval forms, and to small numbers of young herrings obtained in the 

 same way — and so far as his research was carried it agrees well with 

 my own. He did not attempt to deal with the growth of the older 

 series of herrings, except in a few cases, but made certain calculations 

 as to the rate of growth per month. In the following Table I give a 

 summary of the results of Jenkins (as amended by the intercalation of 

 a year, so as to make his annual series a year older than he represents 

 them), and also of the results of Masterman on the spring herring, as 

 far as they go, and the approximate sizes of the older series as calculated 

 on the basis he gives, viz., a growth of from 4mm. to 5mm. per month. 

 The latter is quite accurate for the early stages, but it is rather wide of 

 the mark for the older herrings, owing to the diminution of the rate of 

 growth with age that actually takes place. 



