888 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



I now proceed to give a few rules of general importance for the con- 

 struction and management of carp-ponds. 



The ponds should have as shallow a border as possible. Their 

 depth should be in accordance with their size, one foot in the culture 

 or regular carp-ponds where large fishes are kept ; ^ foot in breeding 

 and ^ to ^ foot in hatching ponds. The borders should be of consider- 

 able width ; it is desirable in any case that a great number of such- 

 shallows be contrived in ponds, as these are the principal feeding- 

 places of the carp. 



A.nother important condition to be considered is this, that the water 

 in ponds must be of the same depth all the year round, any variation in 

 this having an injurious influence upon the fishes. 



Ponds of smaller circumference, of from 10 to 15 acres, are, according 

 to results obtained, better suited for carp-culture than very large ones, 

 100 to 1,000 acres in extent. These are frequently found in Central 

 Europe upon tracts of land belonging to some princely domain. In the 

 former the fish finds more security, the bottom of the pond being 

 smoother; it also suffers less from the waves, these being high and 

 rough in large ponds, becoming very detrimental to the spawn and 

 breeding-fishes, especially during storms, when they are cast ashore 

 and become the prey of water fowls or perish in some other manner. 



The diminution of water by evaporation must be made up for by a fresh 

 supply ; this, however, must not exceed the quantity actually needed 

 for maintenance of the regular height of water. Small ponds of from 

 one to fifty acres area, which serve some commercial or industrial pur- 

 pose, as mills, &c., and which are constantly varying the height of their 

 water, cannot be considered as favorable or regular culture-ponds. 

 Although the fishes may grow to a pretty good size in them, they must 

 still be regarded as belonging to the category of waters for '' free fish- 

 ing," like lakes and rivers. In these neither the height of water, nor 

 the hatching of the eggs, nor yet the increase of aquatic animals, can 

 be regulated at will. Still, leaving these waters to lie waste on this 

 account would be a pity, for if stocked with carp they will, in spite of 

 all disadvantages, remunerate the proprietor, and the care which he be- 

 stows on them will be a source of much pleasure. 



I beg to make some remarks, in conclusion, relative to the introduc- 

 tion of the carp and its increase in open waters, in which it is solely 

 left to the care of nature, and to which subject I alluded at the com- 

 mencement. 



We introduce into our waters migrating fishes, such as the salmon 

 and shad, and find it profitable, for the reason that they consume but 

 little food in the rivers, growing up in the sea and ascending into fresh 

 water as large fishes. We also maintain in our lakes white-fish, bass, 

 pike, &c. These are all fond of animal food and belong in part to the 

 class of fishes of prey. The carp, on the contrary, lives upon vegetable 

 food, insects, larvse, and worms, but it never attacks other fishes or 



