316 



Part III. — Twenty-fourth Annual Report 



34'3mm. They were thus about 24-25mrn., or 1 inch, longer than the 

 group in August, and clearly belonged to another and earlier spawning, 

 that is, to the spring series. 



Two of thern, however, which measured 21mm., might possibly belong 

 to the autumn herrings. The numbers in 2-millimetre grouping are 

 these : — 



20-1 22-3 24-5 26-7 23-9 30-1 32-3 34-5 36-7 38-9 40-1 42-3 44-5 

 2 1 8 6 15 19 30 33 25 24 20 10 1 



These young herrings would thus be about 5-6 months old. 



The autumn herrings are well represented in some collections procured 

 later in the year. Thus, on 2nd October, 297 measured from 9mm. to 

 20mm., the average size being about 15mm. On 3rd October, 334. also 

 taken in Aberdeen Bay, measured from 8mm. to 27mm. ( T %— l^g- inches), 

 the size of greatest frequency being 17mm., the average lG^mm., and 

 the mean size 17 -5mm. of an inch). Two of these herrings, again, 

 probably belong to the spring series, measuring respectively 26mm. and 

 27mm. The sizes, arranged in 2-millimetre groups, are these : — 



11-12 13-14 15-16 17-18 19-20 21-22 23-24 25-26 27-28 

 28 54 85 107 47 10 1 1 



The age of these may be estimated at from one to two months. 



The same group is again well represented about a month later, when 

 181 were taken on 6th November, but in a different year. They 

 measured from 12mm. to 25mm. (|-1 inch) — the maximum size rather 

 supporting the suggestion made above, that the two at 26mm. and 27mm. 

 in the October collection belonged to the spring group— and the modal 

 size or mean was about 18mm., the average size being 18' 3mm. (f inch). 

 The arrangement, in 2-millimetre grouping, is as follows : — 



12-13 14-15 16-17 18-19 20-21 22-23 24-25 

 6 17 42 57 40 15 4 



On the 23rd December six herrings were taken, whose measurements 

 were as follows : — 23mm., 24mm., 25mm., and 32mm., 33mm., 36mm. 

 (from yf-l T 7 g- inches), and they possibly belonged to two series. 



On the 12th of the same month, and in the same year, another collec- 

 tion in Aberdeen Bay numbered 15, their sizes ranging from 42mm. to 

 50mm. (l-j-i-2 inches), the size of greatest frequency being 45mm., 

 while the mean was 46mm., and the average 46 , 5mm., or nearly 1{ inches. 



These probably represent the spring herrings, whose average size in the 

 September collection was 33mm., the growth over the twelve weeks 

 amounting to about 14-1 5mm. (§ inch). 



The sizes and increments of these post-larval autumn herrings may be 

 thus summed up : — 



Date. 



Size. 



Range. Average. 



Increase 



Days. 





Mm. 



Mm. 



Mm. 





21st, 22nd August, 



8-11 



9-0 







2nd October, - - 



9-20 



15-0 



: 



42 



3rd October. - - 



8-22 



17 





43 



6th November, - 



12-25 



18 



9 



77 



