the Residence of certain Fishes. 227 
ment regulating the use of trawl nets in Torbay, and hy other regula- 
tions of less value, which have occasionally been made for similar 
purposes. 
In the cultivation of fish in fresh waters., the whole management 
becomes so completely under our command, that there would be 
no difficulty in framing such regulations as increase of knowledge 
would soon suggest, and as private interest would follow, or that 
of the public enforce. 
In what precise manner the regularity of fishing increases the 
supply, or at least does not diminish the production, has not, been 
clearly ascertained. That the several species eat each other's ova 
and young, and even their own, is very well established. Many 
devour each other, even at full growth, and it is not unlikely that 
many also die of disease or want of food. _ In such cases the steady 
removal of the superfluous part of the population cannot check its 
increase. If all the Turks and Egyptians who are to die of the 
plague next year, were to be devoured by crocodiles, there would 
be a certain quantity of food gained, and every thing would go on 
just as before. The empire would not have been a bit less 
populous or prosperous if the Huns and the Ostrogoths had eaten 
each other instead of strewing their own bones and those of their 
antagonists on the banks of the Dauube, or the plains of the 
Campagna. 
_ Respecting the species which might probably succeed in fresh 
water, it is not possible to offer any very rational conjectures. 
It is probable that they might most effectually be sought among 
those genera of which some species are already known to be 
versatile in their habits, In those genera of animals at least which 
- are natural and not artificial, there are considerable resemblances 
among the habits and pursuits of the different species. Thus it 
is not very improbable that as the plaice, the flounder and the mullet, 
have been naturalized to fresh water, the whole of the fishes of 
analogous habits, and particularly those of the genus Pleuronectes, 
might be habituated to inland lakes. The turbot and the sole would 
be very desirable objects of cultivation, If different species of 
Gadus have been shown to be at least indifferent to the quality of 
