THE CARP AND ITS CULTURE. 885 



very close board feuce, 3 to 4 feet high, and going 4 to G inches into 

 the ground. Such a fence will afford no protection against aquatic birds, 

 water-snakes, and muskrats, but it will exclude the snapping-turtle, the 

 most dangerous and voracious enemy of fish, which is more to be feared 

 than either cranes or otters. This detestable animal has been known to 

 clean a pond of fish, and then, led by its sense of smell, to follow the 

 fish, going even up hill and agaiust the stream. At night it seizes the 

 fish, which, not suspectiug any danger, rest at the bottom, with its sharp 

 fangs, resembling shears, and kills them. It is a peculiarity of carp 

 to keep at the bottom during the night, and likewise during* cold and 

 gloomy weather, and the snapping-turtle would therefore have many 

 an opportunity of destroying them. Large iron fish-hooks, with a piece 

 of meat fastened to them as bait, will do good service, if distributed in 

 suitable places on the banks. This should be done from spring to 

 October. The pieces of meat should be of such a size that even large 

 carps cannot bite them ; they will then form a most attractive bait for 

 the ugly monsters. These hooks should be fastened with a strong brass 

 wire, as the snapping-turtle could easily bite through twine, and should 

 be inspected every day. 



In placing spawners in ponds, great caution must be practiced in their 

 selection, so that only really healthy fishes may be introduced, and not 

 such as are affected by fungous growths, the gelatinous polyp, or other 

 disease. In Europe the poJyp, in particular, has frequently destroyed 

 the productiveness of ponds for many years. 



The newly-obtained young fry are left in the hatcbiug-ponds during 

 the winter, after which they are to be transferred to the larger ponds. 



The catching of the young fishes must be done with great care, and 

 the water must be drained off through the grated outlets very slowly, 

 so that no fishes may remain in the mud, for if anew hatching operation 

 is contemplated in the pond, the newly hatched fishes will be retarded 

 in their growth on account of the scarcity of food, this being consumed 

 by any remaining larger ones. The young fishes must be handled care- 

 fully, for the slightest injury of the scales may cause disease and death. 



The breeding-ponds have the same construction as the hatching- 

 ponds; they have dams, reserve-sluices, outlet-channels, collectors, 

 and ditches in the bottom. The only difference is in being deeper and 

 larger than hatching-ponds. They have an average depth of I foot 

 9 inches, and the width of their shallow borders is from 70 to 80 feet. 

 The " kettles " have a depth of 4^ feet from the surface ; their borders 

 are from to 8 inches deep. The growth of grass should also be ad- 

 vanced in these ponds. In small ones of about 4 or G acres, the " ket- 

 tles " may have a length and width of 60 or 70 feet. 



The stocking of the breeding-ponds takes place in spring, immediately 

 after the emptying out of the hatching-ponds; it lasts from the latter 

 part of March until April. 



From 800 to 1,000 breeding-fishes may be calculated to an American 



