532 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [66] 



It will be impossible to lay down rules wLich will apply to every pond. 

 ISxperieiice must gradually tench the proper rules in this respect, and 

 a carefally arranged and punctually kept system of records wdl prove in- 

 valuable— in fact, be absolutely necessary. As a fundamental principle, 

 however, we must state that a pond should never be overstocked. Horak 

 says • " It is not the area of the pond, but the quality of the soil, the 

 qualitv and quantity of the water, and the Hat and easily warmed banks 

 of the pond, which determine the success of the fish. Tt may, there- 

 tore happen that small ponds can sustain a comparatively larger num- 

 ber of fish than large ponds, even if the quality of the soil is the same. 

 %n large ponds the pasture-grounds of the fish are comparatively smaller 

 *hau in small ponds with shallow water and a grassy bottom, these lat- 

 ter furnishino- more and better food and a more suitable place of sojourn 

 for fish The water of large ponds is seldom calm, and the waves 

 are apt to disturb the fish. Large ponds, moreover, have generally 

 sandy banks, while small ponds have a more evenly good soil, and are 

 therefore more conducive to the well-being of the fish. The case fre- 

 quently occurs that ponds having the same soil difter greatly from each 

 other in other respects, and that ponds with poor soil are m reality 

 bettor for the fish than those with good soil. The reason for these 

 auomalies must be found in the difierence of location. The heat of the 

 sun can often replace the lack of good soil, and the cold water of a pond 

 surrounded bv woods can make even a pond with the best soil a poor 

 one for pnrpo'ses of fish-culture. To place fish of difierent kinds in one 

 and the same pond is not to be recommended, because the larger fish 

 will deprive the smaller ones of their food, although there are cases 

 where a mixed stock of fish in one pond may be deemed advisable. 



As has already been stated, the number of fish to be placed in one 

 pond will depend on their size and weight. On a well-regulated pond 

 farm the fish are, before they are placed in the ponds, separated not 

 only according to age, but also according to weight. My own expe- 

 rience has shown the following figures to be reliable: 



Weight per 100 M' P,^^d3. 



1 to 1.7 



Oue year's fish 1 7 to 2 5 



One year's fish - - -_- ^^^ ^^ g^ 



Two years' iish, small ^^ ^^ ^^ 



Two years' fish, medium ^ .inn 



, „ , , / 1 to iiw 



Two years' fish large ^^^^ ^^ ^3^ 



Three years fish ^.^^ ^^ ^gp 



Four years' fish 



All these subdivisions according to weight, however, will be needed 

 only in large pond farms with a great many ponds, and even then 

 only if the ponds difl"er greatly in their character; the difference, espe- 

 <'ially between the small and medium fish, will be very inconsiderable ; 

 the one year's fish will generally vary in weight between 1.6 and^.o 



* Horak, Teichicirthschaft, 1869. 



