98 FISH CULTUEE 



through the banks of the ponds; but this does 

 not occur when the sides are of concrete or of 

 well kept boarding. 



While, strictly speaking, appliances for shad- 

 ing ponds may seem to come in the chapter de- 

 tailing methods of caring for fish out-doors, 

 rather than in one of pond construction, I feel 

 that it is well to mention it here. A common 

 method is to lay 3-by-4 studding across a pond 

 near the middle, about five feet apart, and nail 

 inch-boards thereon. This method is doubtless 

 as effective as any other but it is neither sightly 

 nor durable, as such a structure speedily be- 

 comes rotten and is soon likely to break under 

 weights of snow. The best shade-covers for 

 ponds of ordinary size for mature fish are made 

 by building a double pitched roof of lumber. 

 Snow cannot break this down, and it is easier 

 to work the net beneath it. Such a roof should 

 cover the middle third of the pond at least ; my 

 experience has been that fingerlings in the nurs- 

 ery did much better when the entire pond was 

 covered and the fish kept in nearly complete 

 darkness. 



Sides and Bottoms. — There is much discus- 



