average niaraber of flies consaaed in Doth controls and exj^eri- 

 mental aquaria was 11 per fish. Subsequently, tne fish in 4 

 aquaria receiving treated flies and 2 in control aquaria were 

 fasted; those fish in the remaining 6 aquaria were fed untreated 

 adult houseflies. 



The water temperature averaged 73° F. , for the twD-?reek 

 period. The fish ate approximately 10 unsprayed flies each day 

 throughout the course of the experiment. No fish were observed to 

 have DDT tremors, or to have died from the effects of DDT. This 

 experiment indicated that (1) gorging on insects treated at a rate 

 equivalent to 1 pound of DDT per acre for 1 day was not lethal, and 

 (2) that delayed mortality did not result from these feedings if 

 the fish were deprived of food for two weeks after consuming the 

 sprayed insects. 



A similar experiment was conducted with bluegills ranging 

 from 50 to 64 mm., in length, witn the exception that the fish 

 were given all the treated adult flies they would eat over a 3-day 

 period. The test fish each devoured an average of 12 sprayed flies 

 per day, as compared with 11 flies each for the control fish. Dur- 

 ing the 9-<lay test, the temperature of the water in the aquaria 

 averaged 72° F. One-third of those that ate sprayed flies developed 

 symptoms typical of DDT poisoning either on the last day of feed- 

 ing or the following day. However, only 1 fish died in the experi- 

 ment, and it had not previously exhibited symptoms of DDT poisoning. 



Consumption by Bluegills and Grapples of Insects 



Sprayed with a DDT Suspension 



Four bluegills (U3 to 56 mm., in length) that were individually 

 given midge larvae treated with wettable DDT (formula l) devoured 11, 

 11, 22, and 41 larvae, respectively. Those eating 11 larvae each 

 died in less than 16 hours, whereas the other fish lived for 12 days, 

 when the experiment was concluded. 



In another experiment, six bluegills (3I to 41 mm., in length) 

 were fed 9 to 13 housefly larvae treated with wettable DDT. The 

 three fish eating the largest number of insects aied v/ithin 12 days; 

 the others survived. 



Each of 16 bluegills averaging 55 mm., in length were fed 

 suspension-treated (wettable DDT fonaula 1) houseflies lor 3 days. 

 The average water temperature was 69° F. Most of the fish devouring 

 8 to 10 sprayed flies were alive 10 days later, when the first part 

 of tne experiment was concluded. Those surviving were fed all of the 

 sprayed housefly larvae that they would devour in one feeding, l&ny 



