(b) Piezo-electric type crystal transducer producing sine 

 curve sound ranging from 12,000 to 70,000 cycles per second. 



(c) "Wampus" - hydraulic (underwater) turbine noisemaker, 

 sound frequency audiblCj disclosure of frequency charcteristics not 

 permitted, but of low frequency, (U. S„ liavj classified equipment) 



(d) Electro-magnetic sound projector, 200 cps to 10,000 cps 

 sine curve sound. Bell Telephone lK-2. 



5. The hatchery pond in which the tests were conducted was approx- 

 imately 60 feet wide and h^'O feet long. The bottom and sides were of 

 marl mud, a carbonate which absorbs sound waves very wello 



6„ In the teste rainbow trout U to 12 inches long were used, as 

 well as a few lU to 2I4 inches in length, and several hundred brown 

 trout approximately 1-1/2 inches long. Turtles, frogs, toads, molluscs, 

 and aquatic insects were kept in live boxes. 



7» In order to measure the reaction of the fish to the various 

 sound waves a special structure was built in the pond. This structure 

 was 100 feet long, 3 feet wide, and 3 feet deep, divided into 10 sections 

 by sliding gates 



80 A typical test was as follows; One hundred fish were placed in 

 each section (total 1,000) „ The transducer (previously adjusted to a 

 given frequency), located at one end of the structure, was turned on 

 simultaneously Ad.th the lifting of all gates. After a given length of 

 time the gates were lowered and the sound turned off. The fish in each 

 compartment were then counted to determine their distribution in the 

 structure. From this (and from observations made during the test) the 

 reactions of the fish to a j;;iven sound could be determined. 



9, After the initial "start" the fish showed no response to 

 continued sound waves of low frequency. 



10 u There appeared to be no response, either initial or otherwise, 

 to the high frequency sounds, 



11. The "wampus" or underwater turbine produced a sound intensity 

 great enough to burst one's eardrums if he should put his head under 

 water. Sound produced by this apparatus caused the fish in section 

 no. 1 to "start". The reaction was only momentary and numerous tests 

 indicated that this equipment had no value for guiding fish. 



12. Successive, small, underwater explosions failed to cause trout 

 to move away from their vicinity. 



37 



