474 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [8J 



heights, especially on the north side, so as to break the force of the wind 

 from that quarter and prevent it from making the water of the pond 

 too cold. It is not necessary that the pond should be located in a level 

 plain; on the contrary, a sloping ground will prove an advantage, be- 

 cause thereby a natural and very inexpensive means is afforded lor the 

 Avater to flow off"; on the other hand ponds located on low ground or in 

 plains have the advantage of receiving the rain and snow water ftoiii 

 the higher ground which coutaius a great deal of fishfood, and which 

 forms a layer of rich mud at the bottom of the pond. 



2. The configuration of the ground. — The plain selected for the 

 laying out of a pond should be even in all directions, and should in- 

 cline only on one side, so that it is i)qssible to drain the pond entirely 

 in a short tinie. If, howe\'er, the plain slopes on several sides, as is 

 frequently tlie case in large ponds or lakes, and if this cannot be reme- 

 died the water should have a chance to flow off' on all the slopes. Under 

 these circumstances, however, the laying out of a pond becomes more 

 expensive, because it necessitates the construction of dikes and contriv- 

 ances for the outflow of the water. The most suitable ground for the 

 laying out of a pond is that which slopes a little towards the center. 

 Within the limits of the pond there should be no depressions, as during 

 the time when the flsli are caught, some are apt to hide in these places, 

 thus making fishing diflticult. Such depressions or holes should, if 

 possible, be filled, and if they are too large or too numerous to do this, 

 the ground is not suitable for the laying out of a poiul, as the fisheries 

 in such a pond will iuAolve too great an exi)ense. If, however, the 

 ground possesses a depression in sucli a i)lace and of such a size as to 

 make it ])ossible to construct the outlet for the Avater near it, it forms 

 a natural reservoir for the fish, which saves a great deal of labor. If 

 there are in the i)on(l large shallow places it is best to construct dikes 

 round such ])laces, so as to }»revent the fish from entering them, and 

 plant these dikes with willows. 



The first object in selecting ground for a pond is to obtain the most 

 suitable depth of water for the fish. As a general rule the average deptli 

 of w'ater best suited for most kinds of fish is 45 to 50 centimeters. A 

 depth of 80 centimeters is not favorable. It is necessary, however, that 

 a ditch measuring 1.5 meters in depth should cross the entire area of 

 the pond from the place where the water enters to its outlet, Avhere it 

 should widen out, witliout changing its dex)th, thus forming a reservoir 

 for the fish and preventing their freezing in winter. In case, however, 

 the pond is never to be used for wintering fish, the dimensions of this 

 ditch may l)e smaller, unless the quantity of water flowing into the pond 

 requires them to be larger. Several small ditches — their number to be 

 regulated by the size of the pond — should run from the shores of the 

 pond to the main ditch, and the ground should therefore slope gently in 

 the direction of these ditches. On gently sloping ground, which, how- 

 ever, would make the depth of the pond too great if the entire area was 



