I was prompted to get out my Ichthyology book to do some research on another topic for a fishing forum.

I found something very interesting in my book in regards to sound layers and sonar usage.

It seems that certain fish migrate from the mid ocean depths ever night to the surface layers. There are hundreds of thousands of these fish. Now my book suggests that sound waves are bouncing off the air inside these small fish's SWIM Bladders. I immediately thought about Dangerous Waters and the way the model the thermal layers in this game.

But I wonder if the Navy Scientist are aware of the effect these fish have on sonar sounds at night vs during the daytimes? Surely they have their own people who are aware of this fact.

These fish dive deep down during the day and they would take the sound layers with them to the mid ocean depths. Then when the goes down they surface and the sound layers are also rising to the top surface depths of the oceans. These fish are feeding on phytoplankton which rise and fall vertically in the ocean as the sun sets and rises again and again.

So at night a submarine may be able to sneak into the littoral waters and not be heard as easily? ????

I was doing research on how a fish's swim bladder expands and contracts to help the fish maintain buoyancy as it ascends to the surface and dives back down again.

Many bass fishermen these days are fishing for LM bass in the deeper sections of lakes and these tournament fisherman are catching big bass from these deep waters and pulling them to the surface and sticking them in the live wells for hours before they are finally weighed and released back into the shallow waters near the weigh in areas. I am concerned that we are depleting (killing) these bigger bass as we stress them and their ability to control the gases in their swim bladders and blood vessels when they are yanked out of very deep water and to the surface in just a few seconds or minutes.

The anatomy of the various fish vary. So not all fish even have a swim bladder and the different types of fish have different abilities to absorb gases in or out of their swim bladders.


But I never figured I would see the fish changing the depths at which sound waves were traveling though the oceans due to the air in side huge schools of fish .