1102 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [2] 



show that many waste places centuries ago produced large quantities of 

 lish, no pond or puddle, be it ever so small, being allowed to lie idle. 



At this very time, when it is the principal object of landowners to 

 make the sale as productive as possible, when the fisheries in our in- 

 land waters are seriously injured by river improvements, by the pollution 

 of the water through industrial establishments, and by reckless fishing; 

 we have every reason to give our fullest attention to pond-culture, all 

 the more as, thanks to the better means of communication, the sale of 

 fish is no longer limited to the immediate neighborhood of the places 

 where they are caught, but as fish can easily and cheaply be sent to 

 considerable distances, an overproduction or a decrease in the value of 

 fish is prevented. 



Many a person will therefore welcome some brief and simple hints 

 as regards the construction and proper management of ponds, especially 

 if he is the owner of suitable land, and has ajustifiable horror of volum- 

 inous manuals and expensive experiments. 



By ponds we understand sheets of standing water of different sizes, 

 which, if desirable, can be laid dry, and again filled with water. Ac- 

 cording to the source from which the water is supi^lied we may distin- 

 guish (1) brook-ponds, (2) river-ponds, (3) spring-ponds, and (4) sky- 

 ponds. Brook and river ponds receive their supply of water from brooks 

 and rivers which either flow through them or are connected with the 

 ponds by means of ditches or canals. Spring-ponds have at their bot- 

 tom or along their edges springs, which, if flowing very freely, makeup 

 for the loss of water from evaporation, and keep the water at an even 

 depth, but if flowing very freely, cause a brook or river to take its rise 

 from the pond. Sky-ponds are those ponds which, without having any 

 supply of water from rivers and springs, are fed simply by the water 

 from the atmosphere which either falls into them as rain, or flows into 

 them from the surrounding higher ground. In accordance with this 

 classification of ponds, these different kinds of ponds possess varying 

 qualities which are either helpful or hurtful for certain purposes, and 

 which have to be taken into consideration in making use of them. Eiver 

 and brook ponds possess the advantage of having a constant supply of 

 fresh water, whereby the overheating of the water in summer and the 

 suffocating of the fish in winter under a thick cover of ice is prevented. 

 In other respects these ponds are unfavorable for certain purposes, 

 because it is difficult or impossible, even by very narrow grates, to pre- 

 vent young fish of prey and other enemies of the fish from entering the 

 river or brook. Springs will prevent the overheating of the ponds in 

 summer, but their temperature is frequently so low as to render them 

 unfit for the same purposes, especially if the j)onds are deep, and the 

 flow of water from the springs is plentiful. If the water comes from a 

 great depth, and does not before entering the pond pass through layers 

 of soil containing air, it frequently contains so little oxygen that the 

 fish are suffocated, especially iinde? the ice in winter. In this respect 



