What are the sound signals of fish? What can be done by discerning the sound of a fish

Fish are sensitive to sound and have likes and dislikes. Therefore, they can make sounds they like to trap them, and make sounds they don't like to hear to expel them. Acoustic fish traps and fish repellents made based on this principle have begun to be used in marine fishing.

According to different purposes, a small acoustic beacon is tied to the fish body or incorporated into its stomach by using continuous, pulsed or other modulation signal sources, and tracked by passive sonar, which is very suitable for field research on the habits of marine organisms. A small sound emitter placed on the seabed to understand the movement of rocks and gravel on the seabed, a kind of acoustic beacon for ships and aircraft in danger, and can send out an acoustic signal to indicate the location of ships and aircraft during a certain period of time when they are sunk underwater. Neutral buoys with acoustic beacons can be used to measure ocean currents at deep depths, such as deep equatorial currents.

Divers often see a strange phenomenon underwater: whenever a fish is injured or frightened, a dangerous shark will come and take advantage of the danger. In the past, it was thought that sharks had a particularly keen sense of smell, but now it has been proven that this is not the case, and it turns out that sharks use the distress signals from other fish as information to find food sources for themselves.

Scientists recorded the sounds of the fish trembling, twitching and ** when they were in danger, and in the sea**, they summoned 18 sharks to circle around the speaker in a few minutes. There are certain differences between different fishing rods and fishing lines, but most of them are fish floating on the fishing line sinking or floating, some fish are all sinking into the water, some are all floating up, and some fish will be tempted at the beginning, at that time the fish float will move up and down, and finally determine the hook, you can retract the rod, it must be that the fish floats up and no longer sinks, or sinks and no longer comes up, and the specific timing of the rod is still judged by yourself according to the actual situation. For example, the kind of float on the casting rod is manifested as the fish will fall down if it is hooked, and the fish float is normally vertical.

Fishermen can use underwater listening devices to measure the location and direction of movement of fish.