428 Fortieth Annual Meeting 



carp, which, in consequence, are thus hindered from develop- 

 ing well and attaining soon enough the marketable size. 



But other carnivorous fishes can just as well be employed 

 to do the same work. When a pond is in question where 

 waters are not habitually disturbed and not subject to too 

 extended droughts during the high summer temperatures, 

 above 24° or 25° centigrade (75° or 76° F.), for the 

 pike substitute with profit the rainbow trout, which is sal- 

 able at a much higher price. Stock with fish nine to 

 twelve months old, putting them into the pond either in 

 autumn or spring at the rate of about 1 50 to 200 per hectare 

 (60 to 80 per acre), and the product of a piece of water 

 ought to be by this means considerably increased. But it will 

 not be amiss to recall the fact that the rainbow trout is far 

 from lending itself to manipulations which are necessary in 

 fishing a pond with the same facility as the carp. When the 

 carp has to be fished out and left for a few days in the fish- 

 ing-place of the pond, which is always muddy at the moment 

 of emptying, the trout, on the other hand, contracts almost 

 always an inflammation of the gills which, if it does not 

 cause immediate death, at least condemns the fish to lead 

 henceforth a languishing and pining life. 



In ponds where the water gets too warm in summer for 

 the rainbow trout, one can employ perch to take the place of 

 the pike. While the pike eats scarcely anything but fish, 

 the perch, compelled by the small size of its mouth to come 

 down to more modest prey, turns to account worms, in- 

 sects and small crustaceans, which are disdained by the 

 pike. The perch thus utilizes nutritive elements which 

 would be lost with the pike. It also profits better from 

 the food it consumes, and grows proportionally more than 

 the pike, on an equal amount of food. According to the 

 richness of the bottom and the resources in food supplied 

 by the water, it is possible, in a pond devoted to carp, to 

 raise also from 100 to 200 perch per hectare (40 to 80 per 

 acre). A pond skirted by woods which supply it with a 

 good many insects, or receiving waters charged with 



