Summary and Conclusions 



Experiments in which midge larvae, housefly larvae, and adult 

 flies, sprayed v^ith a DDT suspension or an oil solution at a rate 

 equivalent to 1 pound of DDT per acre, were fed to fingerling blue- 

 gills, smallmouth black bass, ana largemouth black bass, gave erratic 

 results. Some fish apparently were killed by devouring relatively 

 small numbers of sprayed insects j otners gorged without effect. 

 Sometimes the fish became sick and exhibited DDT tremors but recovered 

 later. Deaths attributable to DDT occurred after variable periods. 



Fish devouring the DDT-oil sprayed insects were usually more 

 easily killed and died earlier than those devouring insects sprayed 

 with a DDT suspension. 



Large fish appeared less sensitive than small fish to DDT-s prayed 

 insects. 



Fish recently removed from nursery ponds where they were well 

 fed invariably survived the effects of DDT better than did those kept 

 in holding ponds without natural or artificial food. Vfell-fed fish 

 that gorged upon insects sprayed with DDT survived in large nvunbers 

 even though they were fasted after the test feeding. Several labora- 

 tory and outdoor experiments indicated that the condition of fish is 

 a very important factor in their susceptibility to DDT poisoning. 



When fingerling smallmouth black bass were fed wettable DDT in 

 gelatin capsules at 50, 100, and 200 milligrams per kilogram of body 

 weight, all fish were killed, indicating that smallmouth black bass 

 are more sensitive to DDT than are goldfish. 



Literature Cited 



ELlis, M. M., B. A. Westfall, and M. D. Ellis. 



1944. Toxicity of dichloro-diphenyl-trichloroethane (DDT) to 

 goldfish and frogs. Science, 100 (2604): 477. 



Ginsburg, J. M. 



1947. Results from feeding mosquito larvae, killed by DDT, to 

 goldfish. Jour. Econ. Ent. 40 (2)j 275-276, 



Hoffinann, C. H. and E. P. Iferkel. 



1948. Fluctuations in insect populations associated with aerial 

 applications of DDT to forests. Jour. Econ. Ent. 41 (3): 464-475. 



Surber, Eugene W. 



1946. Effects of DDT on fish. Jour. V/ildlife Management 

 10(3): 183-191. 



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