Fly Fishing Forum - View Single Post - Selectively keeping non-native fish out of areas
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Old 12-07-2001, 10:40 AM
Eugene Eugene is offline
Join Date: Oct 2001
Posts: 59
OK John, I'll bore you with a little more of this. Ends up I was wrong about the frequencies that have been proven to move fish. Instead of 40-60 Hz sound, people have used sound around 100 Hz to get a response (ultrasound is loosely defined as anything out of human range, or greater than 20 Hz). Definite success has been limited to members of the genus Alosa (specifically American shad and gulf menhadden). There is a lot of well-grounded speculation that the response is an adaptation to dolphin predation, because, other that the navy and 'clicking' dolphin, nothing we know of in the ocean creates 100 Hz sound.

It also ends up that there was some promise in moving smolts with very low frequency sound (15-20 Hz), but apparently not enough to maintain interest and funding. But it may help explain why you don't catch fish after eating beans and sauerkraut!
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