The Farm Fishpond ' 2039 



too, the former must be kept away from the fishpond. The night herons 

 and Httle green herons are beautiful birds and probably do little harm 

 along the public watercourses. Yet in the private pond where fish are 

 more abundant and less easily frightened, they are obnoxious in two 

 difYerent ways: first, from their habit of devouring young fishes; second, 

 from the fact that they are carriers of certain parasites that infest fish, 

 especially the black bass. The shotgun is an effective agent for pre- 

 venting their depredations, but it should not be used unless herons become 

 numerous and regular pond visitants, and until it is evident that scare- 

 crows are ineffective. 



Mink and muskrats sometimes do rr uch damage, the former by capturing 

 large edible fishes, and the latter by burrowing through the pond banks. 

 The steel trap or the poisoned bait, if judiciously used, will keep these 

 offenders in check. One must be constantly on the lookout for muskrat 

 burrows, and whenever one is found, it must be deeply plugged with 

 clay. 



Rubbish accumulations 



After every heavy rain and particularly during the spring freshets 

 rubbish is likely to accumulate at the dam. Ice jams are especially 

 dangerous. All rubbish should be speedily pushed over the dam with 

 poles or hooks and sent downstream. 



The screens at the intake and the outlet often become clogged with 

 floating debris. Mats of green algae often cover them in late spring, 

 and in the fall floating leaves are very trouVjlesome. If the screens are 

 of the sliding type, they are easily removed and cleaned. With permanent 

 screens much of the coarse material can be raked out and the finer material 

 forced through the meshes with a stiff brush or broom. 



Regulation of the water inflow 



In ponds containing warm-water fishes, it is not necessary during the 

 warmer months to have any perceptible current. Some of the most 

 successful fish culturists permit an inflow sufficient only to maintain 

 the proper level of the pond. The loss of young fishes and food animals, 

 which would ordinarily pass through the outlet screens, can be eliminated 

 if there is no overflow at this point. The inflow should not be reduced, 

 however, until the vegetation has commenced its spring growth. 



During the colder months a good volume of water should be allowed 

 to flow through the pond. This will often prevent the formation of 

 a thick coating of ice in the vicinity of the inlet. . It will also keep the 

 fishes, then congregated in the pond basin, well supplied with freshly 

 oxygenated water, and hence reduce to a minimum the danger of suft'o- 

 cation, which might otherwise occur. 



