Fish can be heard with bubbles

Biologists compared the structure of the bubbles of different types of fish and their hearing ability to conclude that this organ of the fish has the function of hearing.

Most types of bone fish have bubbles. Thanks to this organ the fish is able to float on the water and adjust the depth when living in water. Some fish use bubbles to produce relatively loud sounds. Australian biologists have discovered that one of the other functions of fish bubbles is to listen.

From the experimental results on the fish of the emperor fish family (Cichlidae, a common ornamental fish), biologists have discovered that fish's hearing is related to the structure of the bubble. They chose these fish because they have 12,000 species, live in very different conditions and have signs of multi-functional agencies.

Some representatives of the emperor fish family who live in rivers with fast-flowing water or at the foot of the waterfall almost no longer exist, while the species of the same family living in calm waters are the opposite, flaky. Very developed ball.

In some species the bubble also sticks above, into a separate part that extends to the inner ear. The protruding part probably functions like the ear bones and in each species they have a different shape.

Australian biologists have described the neural signals that appear in fish corresponding to the vibrations of sound. Comparing the hearing of different fish species in the same family and the structure of the bubble, they find that the more complex the fish bubble is, the more likely it is that the fish will hear small sounds and frequencies. So much.

Even if the bubble has no protruding part, the bubble still supports the hearing of the fish if it is large enough. For example, in the emperor fish species, the scientific name is Hemichromis, which is quite large, though there is no protruding part, it still senses the sound level of 3kHz.

The researchers also found that if the bubble is small, the fish only recognizes loud sounds. To feel the small sounds, the fish must use 'tricks' to form a bubble connector with the inner ear.