[13] UTILIZING WATER BY FISH-CULTURE. 1113 



makes tlie fish sick and incapable of propagation. Any person using 

 such rough methods should keep away from fish-culture. 



Opinions differ as to the number of spawning fish to be placed in a 

 spawning-pond of a given size, and as to the proportion bet wen the sexes. 

 If all the other conditions are favorable good results may be obtained 

 by different methods. Of late years the common practice seems to be to 

 count per hectare 8 to 10 spawners and 4 to 6 milters of the same size, in 

 addition to which 2 to 3 small milters are put in the pond. For a spawn- 

 ing-pond of 1-iV hectare one would, therefore, take one spawner, a milter 

 of the same size, and a smaller milter or two milters of somewhat smaller 

 size than the spawner. If these fish are taken from a basin with cool 

 water, and jjlaced in a spawning-pond, whose temperature has already 

 reached 15° C, one may with tolerable certainty count on the spawning 

 process taking place on the following day or the day after. The spawn- 

 ing process generally takes place during the early morning hours. If 

 you approach, the pond cautiously about that time you may see the fish 

 swim splashingly round the shallow shores, where they deposit their 

 spawn on plants, or on juniper branches, which for that purpose have been 

 laid in the water, and which may also be used for shipping the spawn. 

 The eggs which are deposited by the spawners, and which adhere to 

 aquatic plants, are impregnated by the milt which is ejected by the 

 milters, and which by the violent movements of the fish is thoroughly 

 incorporated with the water. After a while the eggs may be seen cov- 

 ering the leaves and stalks of aquatic plants in large numbers, and re- 

 sembling transparent or slightly yellow beads of the size of grains of 

 mustard. The number of eggs deposited by a spawner varies according 

 to its size from 300,000 to 700,000, of which of course, especially in large 

 ponds, a large number perish, so that it must be considered a favorable 

 result if 1,000 to 1,500 young fish are produced in autumn from every 

 spawner. In small spawning-ponds, managed in a rational manner, how- 

 ever, it is possible to obtain eight and ten times that number. Carp 

 generally 'deposit their stock of eggs in three periods, separated from 

 each other by intervals of eight or more days, so that in large spawn- 

 ing-ponds one may find young fish of three different sizes. In order to 

 get the full benefit of the productivity of the fish, and to further the 

 growth of the young fish, it will be found advantageous to catch the 

 spawning carp after they have thoroughly spawned once in a small pond 

 (which can easily be ascertained by examining the plants growing on 

 the edge of the pond), in a fish-bag with long wings, and to transfer 

 them immediately to another small spawning pond, where they will soon 

 spawn again. From this pond they may be transferred to another spawn- 

 ing-pond, where they will spawn a third time. Another reason why it 

 is advisable to remove the old carp from the spawning-pond is this, that 

 they diminish the quantity of food intended for the young carp, and even 

 devour some of the young fry with as much relish as they eat larva, 

 worms, and tadpoles. 



