522 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [56] 



culture, more especially caip-culture. It will be self-evident, however, 

 that fish-culture aud the keeping- offish can be carried on more success- 

 fully if one has a larger number of ponds. The smaller the number 

 of ponds — even if they are of large size — the more unreliable will fish- 

 culture be, as it will be impossible to guarantee to the fish that degree 

 of safety which they require at different ages. A complete pond culture, 

 therefore, requires a large number of ponds, which will not only make it 

 possible to raise carj) systematically, but will also offer an opportunity 

 to raise other fish, as trout, pike, &c. Not only every kind offish, but 

 every age, needs difi'erent circumstances and surroundings to insure 

 success. jSTot all ponds have the same soil, the same natural conditions, 

 the same water, de])th, size, &c., but they differ in these respects, and 

 fish-culture must take into account these difierences, if it is to be car- 

 ried on systenuitically and successfully. It will, therefore, be necessary 

 to know which ponds are best adapted to certain purposes, and we shall 

 have to examine what experience teaches relative to the selection of 

 ponds for the various purposes of carp-culture. 



I. SPAWNING PONDS. 



The spawning ])ond is the most important of all the ponds, for it forms 

 the basis of the entire pond culture. On the production of a suitable 

 (juantity of young fry of the proi)er quality the success of pond culture 

 will i)rincipally depend, aud great care should, therefore, be exercised 

 in selecting the si)awning ])ond. 



The following are the requisites of a good spawning pond : A spawn- 

 ing pond should not be very large; it should lie on a level, and be ex- 

 posed to the sun the whole day ; for water sufficiently heated by the 

 rays of the sun is the main condition not only of beginning the si)awii- 

 ing process in due season, but also of its ultimate success, as well as of 

 the hatching of the eggs. Ponds fed by springs should therefore be 

 avoided. Spawning ponds should not be shadeil by trees ; but on the 

 side which is jnost exposed to the wind they should be protected by 

 woods or hills, because strong waves occasioned by wind are injurious 

 to the spawn, and are apt to throw the young fry on the banks, where 

 they will perish. It must becousidered as particularly favorable if on the 

 north and east side there are hills or buildings which reflect the rays of 

 the sun on the j)ond. Spawning ponds should be shallow, because this 

 favors the heating of the water, and their depth should decrease to- 

 wards the shore. They should be crossed by a suitable number of 

 ditches, so as also to afford to the fish deep and cool places. Their 

 depth of water should never be less than one meter, so that there is no 

 danger of their drying out in summer. Spawning i^onds should not 

 only be drained during winter, but they should also be planted the year 

 previous, not only to remove acids from the soil, but also to make sure 

 that there are no pike in it. This method also drives away the frogs, 

 which destroy much spawn. In order to make sure that there are no 



