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Part III.— Twenty -fourth Annual Report 



worth considering their origin. They could scarcely belong to the spring 

 fish of the year, whose growth, as we have seen, is much slower ; the two 

 smaller might be referred to the previous autumn, and would thus be 

 approximately ten months old; the one at 75mm. (almost 3 inches) is to 

 be referred to the spring of the preceding year. According to the rate of 

 growth given by Masterman, herrings of that average size, if spring 

 herrings, would be almost exactly twelve months old, and if autumn 

 herrings, all but twelve months old (61mm.). 



It is, however, to be remarked that herrings of this size and larger 

 are likely to escape from tow-nets, especially when used in daylight, and 

 even from the slowly-towed and larger midwater net ; and thus the 

 average size of the herrings, except the smaller ones in collections 

 obtained in this way, may be expected to be somewhat under rather than 

 to exceed the true natural size for the group. 



If the two smaller belong to the same group as those which had an 

 average length of 42-3mm. on 18th April, the increment in the 82 

 summer days would amount to 15'7mm., or a mean of -19mm. per day, or 

 5'9mm. (\ inch) per month. 



In August we come again on the larval clupeoids. M'Intosh mentions 

 them under date 2nd, from 5 -5mm. to 8mm. In Masterman's tables, 

 seven from 5mm. to 11mm. are entered between 3rd and 9th ; also two 

 at 15mm. and one at 20mm. From the 22nd to the. 30th, 71 measured 

 from 4mm. to 12mm., and one was 19mm., possibly to be referred to the 

 spring series. Omitting the larger, the average for the 71 at the end of 

 August was 6-7mm. This may be taken as the size at which the 

 autumn herring starts the beginning of September. 



In September M'Intosh notes the appearance of clupeoids from 7mm. 

 to lS'Smm., the latter size only after the middle of the month. In the 

 table of Masterman, 184 are entered between the 4th and 7th, of which 

 181 measure from 4mm. to 9mm., and are mostly 6mm. ; one is 13mm., 

 and two are 44mm. (If inches), and no doubt represent the herrings 

 hatched in March or April. 



From 13th to 30th there are 70 in two series, (1) 64 from 5mm. to 

 18mm. and mostly about 11mm., (2) 6 on 17th from 36mm. to 40mm., 

 the average being 390mm. ; if these are combined with the two taken 

 earlier, the range is from 36mm. to 44mm., and the average size 40*2mm. 

 (1^ inches). 



These are no doubt the spring herrings, which show an increment of 

 8 -lmm. (under § inches) in the 68 days (approximately) from the series 

 of 9th July, or only -12mm. per day. 



On the 7th September two other larger herrings were taken, measuring 

 75mm. and 80mm. (3, 3 J- inches), which no doubt represent the older 

 series taken in July. 



In October, from the 1st to 9th, 34 measuring 7mm. to 19mm., and 

 mostly about 13mm. to 14mm, are entered; from 11th to 19th, there 

 are 82, in three groupings, (1) 4 at 6mm. — indicating a late spawning — 

 (2) 66 from 12mm. to 20mm., most about 17mm. (}| inches) repre- 

 senting the average size at this period, and (3) 12 from 32mm. to 41mm., 

 taken on the 16th and 18th, the average length being 33*2mm. 

 (1 T 5 ^ inches), or less than those taken a month earlier. These probably 

 represent the spring herrings. 



In November, the number is greatly diminished. From the 1st to the 

 8th, 14, from 14mm. to 24mm., and averaging 17*3mm. were taken; 

 and from the 16th to the 24th, other four, from 19mm. to 26mm., the 

 average length for the 18 specimens being lS^mm. (barely f inches), 

 which approximately represents the size of the autumn herring in 

 November, some specimens, however, attaining a little over 1 inch. 



