lure sound question

[vdaiuto]

mr dahlberg, the show you did about lure sound was very interesting.wich got me to thinking.how does sound equate to surf.the show was mainly on lakes and i know how sound attracts marlin and sharks but how about surf ? i mean throw on the waders and grab a 10'rod surf .here in ct. when fishing backbays and estuaries i do great on 7"mombos ,thundersticks & redfins.all have a rattle chamber. in the "surf "of long island sound the numbers are better with old danny plugs,superstrikes,big mamas,old atoms(wich im running real low on)wich have no sound only vibration. does sound matter in surf ? does this hold true for inshore fishing ? thanks in advance.

[dahlberg]

I'm sure sound matters everywhere. In some places, like where there's heavy boat traffic or surf I'd reckon a fish has to sort through the ambient noise to identify prey.
best,
L

[YakMan]

Ive been thinking about this a little bit lately and did a quick google search tonight. Very interesting thought if you compare what makes us like a certain song or style of music. There is something in the frequencies we hear that appeals to us. It would be interesting to see if there are any direct correlations between certain frequencies attracting specific species.

While the research paper referenced seems to take an angle of sound used for navigation, i.e. submarines, there are interesting concepts as to the variables of pressure, temperature and salinity.

http://www.fas.org/man/dod-101/navy/docs/fun/part08.htm
8.4 SPEED OF SOUND IN THE SEA

From physics it will be remembered that when gas is the transmitting medium, the denser the gas, the slower the speed of sound, and yet the speed of sound in water is about four times greater than that in air. Although this seems contradictory, it is not, because there is another more important factor that influences the speed of sound. In truth, the speed of sound is determined primarily by the elasticity of the medium and only secondarily by the density.

8.4.5 Sound Speed Equation

Dealing with these three factors to arrive at values for bulk modulus and density, and thence sound speed, is very cumbersome. To overcome this, numerous empirical relationships have been developed for converting the three factors directly to sound speed. A simplified version of such sound speed equations developed by Wilson in 1960 is present below.

c = 1449 + 4.6T + 0.055T2 + 0.003T3

+ (1.39 - 0.012T)(S - 35) + 0.017d (8-11)

where

T = temperature in degrees Celsius

S = salinity in parts per thousand

d = depth in meters

Given accurate temperature, salinity, and depth data, this equation is accurate within 0.6 meters/sec, 96 percent of the time. By way of contrast, the equation for the speed of sound in air is approximately

c = 331.6 + 0.6T

In making calculations involving the transmission of sound through the sea, it frequently is adequate to use a standard speed rather than the more accurate value given by equation 8-11. Although in seawater c can vary from a low of about 1,420 m/s to over 1,560 m/s depending on environmental conditions, a standard speed of 1,500 m/s may be assumed for computation purposes unless otherwise noted.

[nstenni]

i don't feel that the speed of sound under water is realative in the situation. ( unless the density of water can actually change the speed of the sound waves or frequency of the noise you are trying to produce). the speed of sound would only determine wether fish hear your lure and you have already reeled in all the way and are casting to a new spot.
if you are concerned about the surf or any other noises making the difference in your lure, maybe you could focus on changing how loud your lure is. i would try different materials as rattles inside the lure. lead rattles may produce different than steel tungsten brass ect. just a thought. i never actually really fished salt water.

[YakMan]

nstenni - i get what you are saying but I do think the speed does have a part although not as important as the frequency the lure produces. Fish use their lateral lines and react to vibrations caused by sound waves so I believe sound is very important. If you can match the frequency and the decibel level then the sound will amplify in the water attracting fish. If the decibel level is too loud for instance, the lure may attract fish from a distance but as they get closer the lure will be too loud and possibly turn them away. Maybe it will just get the fish pissed off inducing a strike.... its hard to say without giving it a whirl.

I use shrimp-like lures often so I ask myself how can I make that more effective. If I can find the shrimp beds and match the frequency and decibel level, then in theory I will attract more fish with a very realistic presentation.

I found this next bit in the article interesting with regards to shrimp beds and sounds fish make.
======
A shrimp bed is capable of producing an uninterrupted crackle resembling the sound of frying fat or burning underbrush. Frequencies range from less than 1 to 50 kHz. Noise is constant, but there is a diurnal cycle, with the maximum level at sunset. Over beds, a pressure level of 86 db re 1 Pa has been noted. Intensity drops off rapidly as the range from the bed increases. Lobsters, crabs, and other crustaceans may make minor contributions to background noise.

Fish produce a variety of sounds that may be placed in three categories, depending upon how the sounds are caused. The first category includes sound produced by the air bladder, a membranous sac of atmospheric gases lying in the abdomen. The sound is caused by the movement of muscles inside or outside the bladder or by the general movement of the body. The second division includes sounds produced by various parts of the body such as fins, teeth, and the like rubbing together. This noise is called stridulatory sound. The third class includes sounds that are incidental to normal activities, such as colliding with other fish or the bottom while swimming, biting and chewing while feeding, and so on.

The majority of the sonic fish inhabit coastal waters, mostly in temperate and tropical climates. Although fish are the most pre-valent, and therefore the most important, sound producers, their activity is not as continuous in intensity as that of snapping shrimp. The level of sound produced by them increases daily when they feed (usually at dawn and dusk), and annually when they breed. Fish sounds range in frequency from about 50 to 8000 Hz. Sounds of air bladder origin have most of their energy concentrated at the lower end of this spectrum, 75 to 150 Hz, whereas stridulatory sounds characteristically are concentrated at the higher end of the spectrum.

[YakMan]

Had a customer/fishing buddy come into my store the other day with a little battery operated motor similar to the ones used in cell phones to cause the vibration ring. A friend of his gave these to him saying he put them in a red water balloon(not inflated just for water protection), tied it to his line just above a treble hook and dropped it down. The bite was amazing and instantaneous but couldnt really target bigger fish. Anything close big or small nailed it.

I did a quick google search on cell phone vibration motors and there are lots of styles out there small enough to go in a lure. The question is how to make water tight and still be able to switch on off. Once the battery is dead its done but Im thinking you could get a lot of big fish if it was inserted in a way that was fishable.

Any thoughts on this or know of anything out there commercially available?

[nstenni]

i had a jig once that when it was in the water it put out electriconic signals of wounded bait fish. wether it worked or not is beyond me but i have to imagine that the thing turned on when it touched water. i would imagine that if you were to try a lure with the cell phone motor, there would be a way to use something like that as an on off switch which would allow you to make it water tight for at least a little while. wish i knew what brand it was. that would be a little more help. i like the concept. also i understand what you mean on your previous post now in regards to sound and distance. interesting. good luck

[nstenni]

one quick little add on. it seems a bit upsurd but i think i have another idea on how your motor could turn on and off in the water. you know during easter they have those toy baby chicks that peep if you set them on your hand. well if they hit water they chirp ( until they short out). something like that on a water tight lure would help at least pro long the life of your battery. crazy yes but it may work

[YakMan]

good call nstenni - I was thinking the same thing - use the water to create the ground for the circuit somehow

[Terry G.]

you could use a similar water switch as what Hummingbird uses as in " Humminbird RF45 Advance Remote Sonar Sensor "