I 



On the Naturalization of Fish. 325 



to ascertain, in any view of economy, or management, would be 

 the proper balance of species ; to discover what l^gj^ WPgM$9 lo 

 live together that all the species might find food ; might breed, 

 each to its useful limits, so as to be serviceable to ourselves, the 

 keepers of the flocks, and without hazard of the extermination 

 of any kind. I may illustrate what is here meant, by a simple 

 fact, in the ordinary economy of fresh water fishes in con- 

 finement. Pike and perch can live together, because the natunjk^ 

 defences of the perch prevent the pike from exterminating the 

 race, voracious as the enemy is. If trout and pike were con- 

 fined in a narrow water, the trout would be destroyed. 



Or otherwise, it must be our object to ascertain, in an econo- 

 mical view, how to feed, by means of species that we do not 

 desire to eat, those which we do cultivate for our own uses. 

 This is a difficult question, which can only be overcome by 

 time and experience ; by knowledge ; by knowledge, when we 

 are in a state of entire ignorance ; ignorance of every thing that 

 relates to fishes, as great as if they were the inhabitants of 

 another planet. This was one great source of difficulties with 

 us in this case ; and I, myself, must plead guilty, I fear, to a 

 general recommendation of introducing every fish as a mere 

 matter of trial ; the result of which has been mischievous. The! 

 basse appears to have been the great enemy ; to have eaten up 

 the greater number of many species, and given no return. It 

 has proved the pike of this pond. This could not have been 

 foreseen; it is a caution for future speculators. Others will be 

 discovered in the course of trial. It appears also that the com- 

 mon crab has proved destructive, probably by eating the spawn 

 of larger fishes. From some enemy or other, the eels, which at 

 first abounded to an incredible degree, have most materially 

 diminished, and so have the shrimps. The latter, at least, ap- 

 pear to have been destroyed by the basse. Time and trial will 

 teach us what to do do in this case ; in the infancy of ignorance, 

 man might have supposed that he could keep wolves and sheep 

 in one field, and have constructed a pen for foxes and fowls, 

 rabbits, and weasels. We must not accuse nature of our own 

 ignorance. 



The question is here a difficult one ; but a little more study 

 of the general habits of fishes, merely as we know them already, 



