OF THE GRIMSBY TRAWL FISHERY. 373 
and differs in different markets and to some extent with the fluctua- 
tions of any one market, so that in dealing with the question from 
the purely biological point of view this criterion may be left out of 
consideration altogether ; but in endeavouring to arrive at a practical 
solution one is compelled so far as possible to take a view which 
shall comprehend at once all aspects of the question. A practical 
solution may be defined, I suppose, as one in accordance with the 
dictates of common sense,—a quality, by the way, which is usually 
most strongly claimed by those who have the greatest need of it. 
Deferring for the present any attempt at a harmony between the 
biological and the market standards of maturity, we will at the moment 
confine ourselves to consideration of the former. 
To Dr. Wemyss Fulton belongs the credit of having been the first 
to endeavour to ascertain the size at which fish of different kinds 
begin to breed, and, in consequence, to fix a limit of size which would 
divide the sexually mature from the immature forms. His paper, 
which is based on material from the east coast of Scotland, will be 
found in the Kighth Annual Report of the Scotch Fishery Board. 
The next contribution to the subject was from my own pen, as the 
importance of the results obtained by Dr. Fulton suggested to me the 
advisability of making use of the records of the Royal Dublin 
Society’s Fishery Survey, to continue the work as far as these 
afforded opportunity. My paper, contained in the ‘ Scientific 
Proceedings of the Royal Dublin Society,’ vol. iv, pt. vu, followed 
pretty closely the lines laid down by Dr. Fulton, but introduced a 
new consideration. Fulton’s lmit was based upon the size of the 
smallest mature specimen, without regard to sex. Now it appeared 
from the writer’s remarks, as well as from my own observation, 
that there was a difference in the sizes at which fish of opposite 
sexes arrived at maturity, so that a limit based on the smallest 
mature example of the species must exclude from its benefits many 
immature forms of that sex which grows to the largest size before 
beginning to breed. ‘This is, in nearly all cases examined, the 
female ; it is also more plentiful than the male ; and it seemed to me 
that the limit might most usefully be based on the conditions of the 
larger and more important sex alone. It was evident that, even in 
one sex, all fish did not become mature at exactly the same size, but 
IT had not sufficient material for the deduction of a satisfactory 
average, and accordingly fixed the provisional limit at the size of the 
smallest mature, or nearly mature, female that came under my 
notice. I was inclined to suspect that further inquiry would show 
considerable variation of size in relation to locality, a suspicion 
which has been amply justified. 
On entering the service of the Marine Biological Association in 
