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John Desjardins 12-05-2001 10:45 AM

Selectively keeping non-native fish out of areas
My morning review of things for work today lead me to this press release that talks about how some Australians are attempting to keep carp out of some wetlands. Apparently sending a 20 Hz sound wave into the water scares the carp away.

This makes me wonder 2 things.

Are there frequencies that work with other fish?

What frequencies do fisherman emit when fishing?

juro 12-05-2001 12:33 PM

I emit a very strange frequency when I lose a fish... I know it works on birds in the area :D

This is really a good topic though, beats the heck out of chemicals.

Eugene 12-05-2001 02:50 PM

Most of the work has been done with members of the herring family in order to keep fish out of water intakes at various power facilities. There was some effort to use sound to move salmon and steelhead smolts away from turbine intakes but that was unsuccessful. I've never heard of the work done on carp before this.
A guy I work with has done some work with American shad and sound avoidance lately. He's trying to scare shad away from gear that is supposed to be sampling salmon smolts. I thinnk he's using 40 to 60 Hz sound. Apparently, it has shown some promise.

John Desjardins 12-06-2001 11:22 AM

This is interesting before yesterday I had thought that if you wanted to scare off fish you'd be in the ultrasonic range or have a sudden noise. Instead it's down in the lower end of sound that we can hear.

I'll have to think of how, if at all, this affects equipment selection.

Juro, I know that sound :( . The other sound that crossed my mind was those on the day after someone served beans and sauerkraut for dinner :rolleyes: while camping. For some reason Ive never caught much on those days.

Eugene 12-07-2001 10:40 AM

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!

Todd Ripley 12-12-2001 02:45 PM

More importantly, what frequencies ATTRACT fish?

Why stop at lighted lures? How about battery powered flies with speakers?

"Here fishy, fishy".


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