rSO REPORT OF COMMISSIONER OF FISH AND FISHERIES. [114] 



excrements needed for our example, we would — presuming with Delius 

 that on an average they contain 3 per cent of albumen — need not less 

 T:han 3,600 pounds, which at the lowest rate (GO pfeunige [15 cents] per 100 

 pounds), would cost 216 marks [$54]. In using this food there would 

 consequently be some saving, but it is doubtful whether the same fa- 

 vorable results will be obtained as with ground meat, because the pro- 

 portion of nutritive substances is not so favorable, and because the fish 

 would need an enormous quantity of it. It may, however, be assumed 

 with absolute certainty, that even if fish guano is used as food, the in- 

 crease of weight will be greater than if the 2,000 fish in one pond are 

 ^confined to the natural food supplied by it. For in this case the quantity 

 •of food will decrease as autumn ai)i)roaches, while by employing arti- 

 ficial lood the daily quantity of food needed for the fish is regularly 

 supplied throughout the entire period of their growth. The saving in 

 the use of excrements is only a seeming one, as owing to their volume 

 the transportation will involve considerable expense. To convey the 

 3,600 pounds to the pond would require twenty trips by cart, which, 

 including loading and unloading, ^vould come to 3 marks [75 cents] a 

 trip. It must also be qiu\stioned whether the percentage of albumen iu 

 excrements, as given by Delius, is absolutely correct, and I tliLnk the 

 circumstance has been lost sight of that only their digestible parts are 

 of any value. Counting the digestible quantity of albumen — on the 

 basis of the table given above — at 0.5 per cent (which, as we should 

 state, refers only to the excrements of horses, which of all excrements 

 contains the largest quantity of indigested matter) we would need not 

 less tlian 211,600 ])ounds; but even supposing that the digestive power 

 of the carp is twice as great as that of cattle, and consequently instead 

 of 0.5 that 1 per cent was digested, we would still need the enor- 

 mous quantity of 105,800 pounds to equalize the nutritive value of 1,560 

 pounds of ground meat. It will easily be seen that even if these excre- 

 ments were otherwise of no value whatever, this method of feeding would 

 prove exceedingly uui)rofitable. 



Animal excrements may be used as an occasional addition to the 

 food contained in a pond, and will, if so used, always yield astonishingly 

 favorable results, probably because the natural food contained in the pond 

 will be suitably supplenuiuted thereby; but to use them as an exclusive 

 article of food can hardly be recommended. There will, however, be 

 many opportunities of using other concentrated articles of food, e. <;.,, 

 blood, horse-flesh, refuse iVom slaughter-houses, t&c, at comparatively 

 much cheaper prices than ground meat, and with the same favorable ' 

 results, either if used by itself or in connection with ground meat. 



Another question remains to be answered : Would it be advisable, 

 even in ponds having their normal stock of fish, to add artificial to the 

 natural food during all summer, or at least during part of it 1 After all 

 we have said, this question will have to be answered in the affirmative.' 

 Another reason why this may be recommended, is the fact that carp 



