120 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
and others—so long as the men can be trusted to discrim- — 
inate between the sole and the solenette—and while I 
would use every endeavour to get all the young soles 
returned to the water as speedily as possible in the hope 
of their recovery, | would allow the solenettes to be kept 
on board and made any possible use of. 
If, as those best qualified to judge all seem to think, the 
sole fishery is declining because of the increasing scarcity 
of soles in our inshore waters, I would urge most strongly 
that steps should be taken at once by artificial fertilization 
and hatching to add to the numbers of the young in the 
district, and so increase the chance of a fair number survi- 
ving to maturity. [tis undoubtedly more important in such 
cases of diminution to add to the numbers of the fish in the 
area than to put restrictions on the fishing. It may some- 
times be necessary to do both, but the former (adding to the 
numbers) is the most efficacious step and the latter (restrict- 
ing the fishing) taken alone may be useless if the fish 
population is much reduced. It probably holds good for 
all communities of animals that if they fall in a particular 
area below a certain level in numbers, and no fresh blood 
is imported, then they are doomed to extinction—the 
reason probably being that the number of young produced 
in each season 1s not sufficiently greater than the number 
killed off by normal (7.e., regularly acting) causes to allow 
of a sufficient balance being present to meet the action of 
any abnormal (v.e., unusual) causes, consequently at any 
time the existence of the reduced community may be 
threatened by some so-called accidental occurrence which 
would have comparatively little effect in a large community. 
I do not say that the sole fishery has arrived at this con- 
dition—it has happened with the Oyster fishery in various 
_places—but the way to avert such a calamity is to meet 
it in time by artificial breeding and hatching, and so, 
