[oucorry]

A Bass's Sense of Hearing

In water, sound is transmitted as waves of changing water pressure. Thus, a perfectly silent step on the bottom of a carpeted boat can make a sound (a pressure wave) that is "heard" by a bass.
Your boat is constantly acting as an underwater, sound transmitting antenna, and it is amazing how well a bass can hear what is going on in a boat.
Much to our benefit, not all the things bass hear spook them.
Bass hear through four separate organs, two inner ears and two lateral lines. A bass's sense of hearing is much better than man's, and water transmits sounds five times better than does air. Never doubt that a bass can hear the noises you make in your boat. But we need to differentiate between two entirely different types of fisherman sound.
Two fishermen talking are making sounds in the air that might bother other fisherman, but their talk will not bother the bass. Why? because air sounds are poorly coupled into water through the air/water interface.
Sounds that occur entirely in the air seldom spook fish
On the other hand, sounds made by striking the boat are transmitted extremely efficiently into the water and often spook fish, even quiet events that go unnoticed by boat occupants.
Digging around in a tackle box, opening and closing rod box lids, dropping pliers on the floor, and the like, are all sounds that alert bass to your presence.
These are also sounds that may or may not spook the fish depending on how deep they are, how wary they are and what types of sounds they have become accustomed to.
The shallower the fish, the more apt they are to spook from a sound. A lot of fishermen catch fewer shallow bass than they should because of noises made in the boat.
A bass can hear both gas powered motors & trolling motors. When they are feeding shallow they tend to spook off a big motor more so than a trolling motor.
Therefore, when approaching a shallow fishing area, you should shut down the big motor about 100 feet from your fishing spot. Then get organized; do all the digging that needs to be done in tackle or rod boxes. And finally when you are ready to be quiet and start fishing use a low setting on the trolling motor to close the final 100 feet.
Trolling motors do not spook bass, but they can certainly hear them. And pressured bass have learned that trolling motor sounds mean there are fishermen nearby. Experience has taught us that a trolling motor does not spook a bass, but more recently we have learned that trolling motors tend to alert the bass to our presence. Therefore we try to keep our trolling motors on lows and we pulse them as little as possible.
The bass's inner ear is a spherical cavity with a ball suspended in liquid, in the middle of the sphere. The ball is held in the middle by sound sensing nerves and tissue. The two inner ears are buried under the skull on each side of the fish's head. Sounds are efficiently transmitted through the water, through the skin then through muscle anal bone to these inner ears. In addition, bass inner ears are augmented by lateral lines that are used to hear lower frequency sounds. There is a lateral line on each side of the bass, and each consists of a series of nerve cells that run the length of the fish.
The right side of the bass senses a sound wave at a different time than the left side. Additionally, small differences exist in signal strength and arrival time, as a sound wave strikes various lateral line sensors.
Thus lateral line nerve endings give bass an extremely accurate sense of direction. At short ranges a bass knows exactly were a sound is coming from and whether it sounds like something edible.
Few fishermen finally appreciate the importance of a lure's sound to whether a bass strikes it or not. We think that bass make bite/no bite decisions primarily based on sight, but they will still reject a lure if it does not sound right.
Bass are attracted by some sounds and repelled by others. Not many years ago it was discovered that rattles in baits call attention to the bait and increases the odds that a bass will bite.
Because of this phenomena more and more baits have built in rattles, and a lot of fishermen are putting rattles in their plastic worms, in their spinnerbaits, and they are also attaching rattles to jigs.
More recently, a few professional fishermen have decided that rattles are being overused. These fishermen suspect that some bass have learned that rattling sounds means artificial lures that should not be eaten.
We aren't convinced that this phenomenon has occurred, but we believe it will in due time.