THE HISTORY OF FISH-CULTURE. 493 



B— EEPORT ON THE rROGRESS OF PISCICULTURE IN 



RUSSIA. 



By Theodore Soudakevicz. 



[Prepared for the Vienna Exjiosition of 1873. and translated from the French by H. 



Jacobsen.] 



1. — THE DECREASE OF FOOD-FISHES. 



The fact that basins which formerly abounded in fish show a 

 decrease does not admit of any doubt, and it is even asserted with good 

 reason that this is not an accidental phenomenon, which might be 

 explained by unfavorable and passing circumstances, but that we have 

 to face a constant and general fact. 



In view of the great importance of the fisheries in regard to the 

 question of food and economy, this decrease of fish must necessarily 

 occupy not only scientists and naturalists, but also governments. Ob- 

 servation and experience have shown that the cause of this fact must 

 not be looked for in a weakening of the reproductive powers of fish, 

 which probably are as extraordinary at this day as they were in former 

 times ; * it must, therefore, be due to other influences, especially to those 

 which are brought about by man's own doing. 



The basis on which a rational system of pisciculture is founded is 

 very simple, and can be limited to the following rules : 



1. Preserv'e the natural conditions of those places where the fish 

 spawn, conditions which favor the spawning-process, and tend to pre- 

 serve the spawn and protect the first development of the eggs ; thus, 

 e. g., everything which diminishes the supply of fresh water; everything 

 which changes the quality of the water or the character of the bottom ; 

 everything which hinders the growth of aquatic plants; in fact, every- 

 thing which at its very source can destroy' the wealth of fish of a whole 

 basin. 



2. Leave a free passage for the fish to pass to the places which are 

 favorable for spawning, at least as much as is necessary for pre- 

 serving the species in sufficient quantity ; for the best natural condi- 

 tions for spawning would be useless, if nearly all the fish which went 

 there were caught and destroyed during their journey. 



3. Protect the young generation, so that it can arrive at the age of 

 maturity and contribute its share toward the increase of the species. 



If these conditions are observed, every large sheet of water, inland 

 seas and large lakes, may become as rich in fish as the quantity of 

 nutritive substance contained therein will permit. Certain hurtful influ- 

 ences such as, epidemics, or the too great development of animals 

 which feed on spawn, can doubtless diminish the number of certain 



"Thus, the codfish deposits 9,000,000 eggs at one time; the tench about 350,000; 

 the perch, 300,000 ; the carp contains 50,000 eggs to every pound of weight ; the pike, 

 40,000; the salmon, 25,000, &c. 



