476 REPOKT OF COMMISSIONER OF FISU AND FISHERIES. [10] 



Especially iu the case of lakes formed merely by raiu or suow water, 

 wbicb are to be transformed to fisb-pouds, it will be absolutely nec- 

 essary to ascertain whether during a period of many years there was 

 ever any lack of water, what is their usual depth of water, and whether 

 this depth remains the same during winters when there is but little 

 snow and during dry summers. Even if this should be the case, it 

 will always be advisable, in order to be sure of success, to fill such 

 "sky ponds" immediately after the autumn fisheries. In order to se- 

 cure a permanent and even depth of water in such ponds, they should 

 have as many feeders as possible, so that at every rainfall, and during 

 the thaws of spring, all the water from the surrounding country may 

 flow into them. 



Before laying out such ponds one ought to ascertain whether, in case 

 of necessity, lea\'e will be granted to carry these feeders or ditches 

 through territory belonging to other persons. Water obtained through 

 such feeders generally carries a great deal of fish-food into such ponds. 

 If there is no diiliculty about filling tliem'\vith water — and tliere gener- 

 ally is no dilficnlty as regards "sky ponds" measuring 30 to 40 hec- 

 tares (and even more), if one does not shun the expense of supplying 

 them with water from distant regions — they must, especially if the soil 

 is of tbe right kind, be considered as among the very best ponds, as, 

 owing to the excellent fish-food carried into them by the feeders, the 

 growth of the fisli will be rapid and healthy. 



4. The quality of the water. — It is certain that some kinds of 

 water are better adapted to fish-culture than are other kinds, but, as a 

 general rule, persons, in laying out a pond, will not have much choice, 

 but will have to take the water as it is, as its quality depends on the 

 nature of the country and other circumstances which cannot be changed. 

 We have already mentioned from what points of view and in what man- 

 ner water should be examined, before using it for a fish-pond, and we 

 may here simply refer to what has been said before. Water containing 

 any substances which are injurious to fish, and which cannot be purified, 

 should of course not be used for fish-ponds. If no other water can be ob- 

 tained, the idea of starting a fish-pond in the locality should be forthwith 

 abandoned. As a general rule those ponds seem to be the best whose 

 water is supplied by brooks and other small but never-ceasing streams. 

 The water, however, should not comefrom forests in theimraediate neigh- 

 borhood of the ponds, as it is apt to be too cold, and contains but little 

 fish-food ; while water, which, j)rior to its entering the pond, flows for 

 a considerable distance through cultivated ground, will be much warmer 

 and be saturated with nourishing matter, thus being iu every respect 

 suitable for a fish-pond. 



Director Horak says the following relative to the advantages and 

 disadvantages of the different kinds of water which are used for sup- 

 plying fish-ponds: " Such waer is either — 



"«. Pure sjpring icater, which (iont-dius but little fish-food, is gener- 



