Ronje

Found quite a few references with a search. What a treasure trove of the information I've been seeking and enough to keep me occupied for yonks. Fascinating how nature has provided and refined (after thousands of years of evolution) tools that fish need to survive. The equivalent of a fish lateral line sensory system to find the source of something has only been developed by man in the last 75 years of technological advancement. (mobile Commutated Antenna Direction Finding Systems....CADF) And man thinks he's clever. Thank you.

Thanks Dave. Lateral lines are designed to operate at very low frequencies eg 10 hz so are below the range of fish hearing. Incoming sound waves pass through the fish's body and move the swim bladder. Attached to the swim bladder is a anvil and hammer (similar to humans) which operates via the swim bladder to "magnify the sounds waves. These are higher frequency noises (100hz - 1khz) than those to which the lateral lines are tuned ( 10khz). For our lure to generate the low frequency pressure waves like a fish, the bib is pulled left and right like you've described. What I'm hung up on is which part of the lure actually generates the low frequency pressure waves (the 10 hz) to stimulate a distant fish's lateral line. Is it the vortices themselves or is it the body of the lure itself pulled pulled sideways rhythmically by the bib action pulling at the head of the lure that causes the pressure waves? If its the lure body (via vortex induced vibration--VIV-- causing the lure to vibrate at the same rate), then damping of the vibration by the body would have to be occurring. So do smaller lures produce less damping? There has to be a way of pre-determining the lateral line vibration frequency in the lure design phase (maybe by bib dimensions or similar). Have your investigations led you in that direction? regards Ronje

Just discovered this site. Trying to get a handle on use of lateral lines. Hope you can help. Is it the vortices themselves that send out vibrations or is it that there are are vortex induced vibrations from the lure body that are emitted?