24,48 percent of the diet. G-cmie or pan fishes and commercially valuable 

 species made up 15,18 percent, and unidentified fragments of fishes amounted 

 to 4.17 percent. Gravjfishes composed 22.27 percent of the total food, and 

 other crustaceans, 10*31 percent i Insects j chiefly aq^uatic species, foiTaed 

 13*41 percent; amphibians (principally frOgsj j 5i96 :)ercent; aid mollusks, 

 0,26 percent. The remainder v.'as made up of vegetable matter, most of ijvhich 

 probably vjas incidentally taken. 



PRSVE^ITIVE .OR CONTHC'L MEASURES 



Because fish-eating birds in m.oderate abundance, under natural conditions, 

 are a public asset, reasonable effort should be made to prevent their depreda- 

 tions upon the desirable fish supply and so avoid the need for destructive 



■control emthods. There is no doubt that some of the birds may cause intoler- 

 able destruction under special conditions, particularly at fish hatcheries 



.or at rearing ponds, and in such situations protective measures are necessary. 

 Most fish-cultural work, however, is supported by public -funds, and those in 

 charge have a duty to the general public to prevent any unnecessary destruc- 

 tion of a national resource, rihether it be fish or fo-^^l. 



' Screening and Yfiring Ponds 



It is natural that fish-eating birds should appear at hatchery ponds, 

 for a virtual banquet table is there set for them. Therefore, every practical 

 means of preventing daraage should be attempted before any destruction is 

 carried out by the use of guns or traps. 



Screening or wiring of tanks or small ponds, as described in Department 

 of Agriculture Leaflet No._ 120, "Excluding Birds from Reservoirs and Fishponds" 

 (copies available free from the Office of Information, U. S. Department of 

 Agriculture, Washington,. D. C), is frequently possible at- moderate expense, 

 and a number of States are now working along this line. Edward R. Hevjitt, who 

 has long been engaged In fish-cultural work, regards it as a necessity to use 

 such, protective measures. In a recent article in Outdoor Life he wrote 3/ : 



"The only sure way to raise trout successfully is to do it in tanks 

 completely screened from vermin. liJlien the trout are 9 1so 10 inches long they 

 can be raised in ponds, if they get reasonable protection from birds and other 

 marauders. When the large fish are put out they remain in the stream only a 

 short time until they are caught. In this way, losses due to vermin are 

 reduced to a minimura. Therefore, the really practical way to get the most 

 •for our money and efforts is to raise the trout in completely protected areas 

 until- they are big enough to bo put into the stroams or groivn still larger in 

 somiprotectcd ponds, - . 



3/ Outdoor Lifo 76 (2): 64, Aug. 1935» 



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