the Residence of certain Fishes. 221 



ment regulating the use of trawl nets in Torbay, and by 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 p'art 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 Danube, 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 



