[15] UTILIZING WATER BY FISH-CULTURE. 1115 



sufQcieut to stock 71 hectares at 1,050 lish per hectare, and which would 

 yield in autumn about 71,000 fish having a total weight of 8,000 to 

 9,000 kilograms. 



On carp farms, managed in the usual manner, one is generally satis- 

 fied to get in autumn 1,000 to 1,050 young fish from one spawner, of which 

 100 will weigh 1 to 2} pounds, therefore in all 5 to 19 kilograms, instead 

 of the 8,000 to 9,000 obtained by following Dubisch's method. 



Although Dubisch's data, which I have not yet had occasion to test 

 practically, are surprising, I do not by any manner of means consider 

 them improbable, as I myself have obtained in a very good spawning- 

 poud, in which the majority of the fish pei^shed by an accident, and 

 where, consequently, there was an ample quantity of food for the sur- 

 vivors, young fish measuring 20 to 22 centimeters in length, and weigh- 

 ing as much as 150 grams. Dubisch's method seems specially important 

 for populating lakes and rivers with these valuable fish, which, placed 

 in them when measuring about 20 centimeters, will grow well, even if 

 their number will not increase much in such waters. 



It is a great mistake to place in large spawning-ponds, besides 

 carp, other fish, especially crucians, as was formerly done quite fre- 

 quently, and is still done in some places. Looked away from the fact 

 that sucb fish, by diminishing the quantity of fish-food, will retard the 

 growth of the young carp, the crucians will with the carp produce bas- 

 tards, which have a high back, and are thin and full of bones. Such 

 fish are the Carpio Kollari Heck., which will soon damage the reputation 

 even of a good carp farm. 



2. THE RAISING-PONDS. 



"Eaising-x)onds" are those ponds in which the young carp are placed 

 to grow. The young fish produced in tlie spawning-ponds are taken 

 out either in autumn or next spring, and transferred to the raising- 

 ponds. 



This may be the proper place, in order to avoid repetitions, to give 

 names for the carp of different age. Yery strange names have been 

 given to them in different places. Thus, people will speak of one year's, 

 two years', and three years' fry, of spawning fry, of deposit, seed, &c. 

 Some will call those fish three years' fry, which others call "one sum- 

 mer's fish," and the confusion of terms has become so great that when 

 people speak of one year's carp they may mean carp of three months, 

 as well as those of twenty months. 



It seems proper to understand by "fry" those fish which have been 

 hatched in spring or early summer, and call them by that name till 

 autumn, or, since carp do not grow during winter, till next spring, or 

 till they have completed their first year. The simplest way, however, 

 is to distinguish the carp by the number of summers which they have 

 passed, therefore, one summer's carp, two summers' carp, three sum- 



