18 Fishery Board for Scotland. 
As has already been remarked, a very different state of matters 
is found to exist in the case of plaice, as has been fully demonstrated 
in a recently-published Report. Let me now take, as one final 
example, the case of the witch. In this fish, as in the plaice, 
though not quite to the same degree, the evidences of diminution 
are clear, and include both the large and small classes of this fish. 
In the curve for the Shetland area (X.) there is no difficulty in 
seeing the evidence of this decrease (fig. 17). 
In the case of the large witches, the catch at the best season of 
the year rose in the winter of 1902-03 to over 6 ewts. per 100-hours’ 
fishing. A year later it was just over 5 ewts., and again a year later 
it barely touched 4 cwts. In the winter of 1907-08 it stood at 
about 2 cwts., and the curve has never since risen even so high as 
1 cwt. An almost precisely similar decline is perceptible in the 
curve for small witches on the same area. 
In Area XIV. (including the Fair Isle ground), the curve for 
large witches reached in 1901 to over 11 cwts. per 100-hours, 
at the best season of the year. In the five years from 1901 to 1905 
it never failed to reach 7 cwts.; but it has almost steadily fallen, 
and now for the last four years it has never reached so high as 2 ewts. 
The fall has not been so steady, but is yet clearly marked for small 
witches upon this area (fig. 18). 
In Area XVIIT., where the witch is comparatively abundant, 
the fall has not been so great; but here also a decline in large 
witches (though not noticeably in smali) has been in progress since 
the year 1905 (fig. 19). 
These illustrations, which might be indefinitely multiplied, must 
suffice for the present. 
They are amply sufficient to show that there are great differences 
between one fish and another in the evidence that they give of 
steadiness or of decline in the average quantities captured on the 
principal fishing-grounds. Of the fishes now or lately considered, 
it is found that a sharp contrast exists between the plaice and the 
witch on the one hand, which show crave signs of diminution, and 
the cod, the ling, and the saithe, of which no such signs of decrease 
can be alleged. 
The reasons for such a difference are not definitely known. Two 
causes at first suggest themselves, one depending on the action of 
the trawl itself, and the other arising from the nature, habits, and 
distribution of the fish. 
It might naturally be supposed that the shape of the flat fish led 
to its easy capture and destruction by the trawl, at a size when the 
round fish of corresponding length slinned through and escaped, and 
that for this reason the destruction of the immature flat fishes was 
disproportionately great. But in the case of the cod, ling, and 
saithe, the greater natural size of these fishes, and the comparatively 
large size to which they must grow before reaching maturity. are 
obvious facts which go against this simple theory. — 
It would seem meanwhile to be a better. explanation, and more in 
accordance with the facts, to say that the decline is most obvious in 
those fishes which are by nature less abundant in our seas, and whose. 
habitat and breeding-grounds are comparatively limited. Tt is 
the fish such as the cod, saithe. and ling. whose habitat is peculiarly 
