1134 REPOET OF COMMISSIONEE OF FISH AND FISHERIES. [2] 



expense. How often does a ditch with running water or a little brook 

 offer an opportunity to transform a hitherto dry area into a pond, and 

 many of our large estates have watercourses which are admirably 

 adapted to this purpose. 



On the estates of Archduke Albrecht, near Teschen and Saybusch, 

 Thomas Dubisch, inspector of fisheries, has introduced into carp-pond 

 culture a method invented by himself, by which the production of carp 

 fry is secured, and by which the yield of the ponds has been considera- 

 bly increased. I will here state what I learned during a visit to these 

 estates. The archducal farmer, Adolf Gasch, of Kaniow, informed me 

 that he had made an improvement on the method of Dubisch 5 but as it 

 was a professional secret, I am unable to judge of it. I am under great 

 obligations to the director of the archducal farms, Mr. W/v '^ler-Uysdal, 

 at Teschen, for his friendly assistance. The carp-raising' pond which 

 Dubisch uses is also adapted to the raising of bleak, tench, crucians, 

 perch, and other fish, which spawn on a soft bottom. The pond need 

 not be larger than 0.1 hectare [J acre] ; and a depth of from 0.3 to 1 

 meter [12 to 39 inches] is quite sufficient. When the water is to be let 

 off, the bottom water should be brought down to at least one-third 

 meter [13 inches] below the bottom of the pond, so that it can dry out 

 completely ; it is therefore crossed by a number of ditches of sufficient 

 depth, whereby all injurious animals, such as frogs, beetles, larvae, &c., 

 are removed and the acids are withdrawn from the bottom. A soft bot- 

 tom of clay, peat, or sand, and the possibility of laying the pond entirely 

 dry, are essential conditions of success. The pond lies dry during win- 

 ter and spring, and is filled with water only a short time before the 

 spawning fish are placed in it. In order to keep strange fish away from 

 the pond, Dubisch leads the water which feeds the pond through a gravel 

 grate, which completely answers the purpose. With laths a box is con- 

 structed, measuring 6 to 8 meters [20 to 26^ feet] in length, which is 

 filled with sifted gravel, varying in size from a hazel-nut to a hen's egg. 

 When too much mud accumulates it is removed by shoveling. A set of 

 spawning carp comprises one spawner and two small milters. Young 

 carp generally spawn more vigorously than old ones; but Dubisch is 

 certain that he has also obtained offspring from spawners weighing 15 

 pounds. The spawning carp and the young carp are during winter kept 

 in a winter-pond, and in spring are placed in a wooden or walled tank, 

 where they do not eat anything and have no desire for spawning. It is 

 best to keep fish of different sexes separatel3^ 



The spawning pond is generally stocked during the second half of 

 May. The carp may be used still later, however, as they do not spawn 

 in the tank. A temperature of the water of more than + 14P E. [63^° 

 F.] is so essential for spawning that the water should be raised to that 

 temperature by artificial means. In this manner Christian Wagner, at 

 Oldenburg, the well-known breeder of goldfish, has caused his carp to 

 spawn as early as March. As a general rule the fish will spawn as 



