Органы чувств играют очень важную роль в fish life and behavior. Fish, like other vertebrates, have a complete set of five senses. But they have a significant difference - the lateral line. In fish, this sense organ is called the sixth. Terrestrial animals in the process of evolution have lost this sixth sense, but in waterfowl it remains and rather significantly facilitates their life, helps them survive and eat.
One of the main senses in fish is consideredSmell and taste. With their help, they are able to catch even minor changes in the environment. Fish, for example, with the help of a mouth, not only feeds, but, feeling a touch to the ground, instantly reacts, changing direction. Sensitive cells in the mouth transmit nerve impulses, signaling danger, obstruction or food.
The fish have a rather subtle temperature sense. Such high sensitivity to temperature and pressure fluctuations is not typical of land animals.
The organs of smell of fish are located on the sidesheads and resemble small cones. With their help, they can catch changes in the chemical composition of water. Especially sharply developed sense of smell in those animals that lead night hunting. For example, pike fish can smell prey that swims a few meters away.
Many scientists believe that the lateral line in a fish isthe most important sense organ that helps animals to be more comfortable. The lateral line is a kind of single center that unites all the sensory cells in the body that are in the head or body.
The body is located all over the body, starting atheads and ending at the tail. The anatomy of fish, their species and subspecies determine the location of the sideline and its color. In one species, it may look like a bright white line, for others - a dark, almost black stripe.
In a larger number of fish, the lateral line is represented insingle copy. But there are some species that can boast five or more. The side line of the fish can be very noticeable visually, and can be hidden in the scales and immediately invisible to the human eye. In some fish, it is arcuate, while in others it is in the form of small jerky stripes on the head.
There are fish that are devoid of the sixth sense organ. These include the mullet, Dallia, and some fish of the family kartozuboobraznyh.
As we have said, the lateral line in fish is a kind of brain and nerve center that allows you to control what is happening around. What does this center consist of?
The side line is a cluster ofreceptors, which are located among themselves with a certain interval. Receptors may be located in the channels on the head or in the recesses, which are located on the sides of the body. Most receptors are hidden under the skin of fish. Only a few come to the surface and are hidden in the scales. They resemble open pores on the skin.
Внутри канал боковой линии наполнен жидкостью.Nervous receptors (their sensitive hairs), picking up the changes, give a signal to this very fluid. Any movement, change in pressure or temperature of water can cause the receptors and, therefore, the water in the channel to move. The stronger the changes in the habitat of the fish, the more the hair-receptors will deflect, the faster the information will get into the central nervous system.
The sixth sense, or sideline, allowsFish feel the approach of other animals that live in the water, much earlier than they are informed about this by the organs of sight or smell. The sideline is capable of capturing the smallest pressure changes in water. Scientists say that the distance at which it is able to determine the approaching danger is six times the size (length) of the fish itself.
The value of the lateral line in fish with low visionespecially great. There are animals that are able to react exclusively to a shadow or light, while completely ignoring the movement in the water. The side line in this case allows you to compensate for the underdevelopment or lack of visual or olfactory skills.
From the sideline often depends on the life of the fish.If it is damaged, then the external effects will be perceived by the animal not so brightly. It will cease to react to danger from the outside, it will not be able to fully hunt, get food, hide from enemies. And soon die.
Surely all experienced fishermen know the value.sideline in fish. With its help, the fish is able to catch the slightest noise and fluctuations of water. As experts say, a shot, an explosion, a usual conversation on high tones, a blow to the water, the sideline immediately “feels.” And the fish, therefore, will react, get scared and disappear. It is for this reason that the fishermen try never to make noise on the pond, not to speak too loudly, not to throw something into the water.
Movement, slight noise and vibrations shouldcreate not a fisherman, but a bait in the water. Experienced anglers say that the bait should not stand in the pond, it must necessarily move, making oscillations of the liquid. Only in this case, the fish with their sideline will smell the food and will move in the direction of the hook.
