of the Fishery Board for Scotland. 323 
(b) The Annual Groups. 
In dealing with the numerous collections of larger herrings, it will 
not be necessary to refer to them all in detail. The method T adopted 
in elucidating the rate of growth and the age of the herrings in the 
various collections was as follows. After determining the rate of growth 
and the sizes for the first and second year, I set down on a very large 
and long sheet, divided into centimetre and millimetre squares, all the 
other collections, showing the range of sizes and the average or modal 
size, that is, the size at and around which the great bulk of the herrings 
in a collection were aggregated. Very little consideration was required 
to allot almost all the collections in a particular month to the proper 
year, and in the accompanying Table I have represented the modal sizes 
of the collections in this manner, and also in some cases (by a cross) the 
sizes of individual herrings or small collections. 
There are a few general considerations that may be referred to. The 
collections were in nearly every case made by means of a small-meshed 
net fixed outside the cod-end of an ordinary large otter-traw], which was 
dragged along the bottom for an hour and more. Several miles of 
bottom were thus trawled over, and this is probably the explanation that 
a mixture of herrings of different series occurs in a few of the collections. 
In most instances this has not happened, the groups being very distinct; 
but in some there are a few, or many, herrings either larger or smaller 
than the limits of the series, and in one or two collections the spring and 
autumn series seem to be more or less blended. They are referred 
to below. 
The larger fully adult herrings are not well represented in the collec- 
tions, probably from their more pelagic habitat. The small herrings in 
their second year are also not very fully represented until the winter, 
doubtless due to the fact that they were able to escape through the 
meshes of the net. They are well shown, however, in the collections 
made in the Firth of Forth by the Garland, with a fine-meshed shrimp- 
trawl, and also in Lochfyne, as above described. 
In May certain collections of small herrings were obtained in the 
Firth of Forth with the small-meshed net around the otter-trawl. On 
the 9th, in from 7 to 11] fathoms, 16] were taken. The smallest was a 
single herring measuring 71mm. (2}3 inches), representing the herrings 
in their second summer, and about one year old, more or less. The next 
measured 94mm. (3+ inches, and was the smallest of a group of 154 
herrings, apparently the largest of which measured 139mm. (54 inches). 
The modal size was 112mm. (4,', inches), the mean 116°5mm., and the 
arithmetic average 114mm. (43 inches). There were other four herrings, 
from 142mm. to 149mm.,and a single one at 187mm. The four referred 
to might belong to the group; but the indications of other series are 
against this view; the series might, on the other hand, so far as the 
millimetre table indicates, have stopped at 130mm. or 133mm. In 
either case, the modal size is unaffected, and the average but slightly. 
On the 10th May, twelve herrings were taken, nine of which were 
from. 117mm. to 135mm. in length, and three from 140mm. to 153mm, 
On the 13th, the collection contained 114 herrings, forming a compact 
series from 97mm. to 126mm., there being another at 133mm., which is 
taken as the end of the group. The modal size was 114mm, (44 inches) 
the mean 115mm., and the arithmetic average 112°3mm. 
If the herrings in this group in the three collections are combined, 
the number is 277, the apparent range of sizes from 94mm. to 139mm. 
(33% to 5,°; inches), the modal size 118mm., the mean 116-5mm., and 
the average 113°7mm. (4% inches). 
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