2007-06-29 05:13:32 · 5 answers · asked by daisy_hilo 1 in Science & Mathematics ➔ Other - Science
Most commercial fish sounders use the 38 kHz frequency. This is the frequency where the fish's swim bladders return the strongest echo.
To find other fish that don't have swim bladders, such as mackerels, other frequencies are used.
2007-06-29 07:33:43 · answer #1 · answered by travelhun 4 · 0⤊ 0⤋
The beam profiling (avoiding too much beam spread) is better with some frequencies of sounds. Also, the wavelength of the sound and the size of the reflector (fish) should match so that the boundaries are clearly delineated.
2007-06-29 05:51:47 · answer #2 · answered by Swamy 7 · 1⤊ 0⤋
Audible sound does not move fast enough through water to be effectively used to identify something moving in water.
2007-06-29 05:29:03 · answer #3 · answered by dusmul78 4 · 0⤊ 1⤋
because underwater sounds are not audible to you if you're above water...and vice versa (that's why hippos have 2 sets of ears, so they can hear above & below water at the same time...fascinating, huh?)
2007-06-29 05:28:52 · answer #4 · answered by speakingofwitch 4 · 0⤊ 0⤋
scares the fishies?
2007-06-29 05:16:31 · answer #5 · answered by witchcraft1701 1 · 0⤊ 0⤋