Sense organs play a very important role in the life and behavior of fish. Fish, like other vertebrates, have a complete set of five senses. But they have a significant difference - the side line. In fish, this sense organ is called the sixth. Terrestrial animals have lost this sixth sense in the course of evolution, but waterfowl have retained it and make their life much easier, help them survive and eat.
Anatomy of a fish. Sense Organs
One of the main sense organs in fish are smell and taste. With their help, they are able to capture even minor changes in the environment. A pike fish, for example, not only feeds with the help of its mouth, but also, feeling a touch on the ground, instantly reacts by changing direction. Sensory cells in the mouth transmit nerve impulses to signal danger, obstruction or food.
Fish have a rather finely developed temperature sense. Such a high sensitivity to fluctuations in temperature and pressure is unusual for terrestrial animals.
The olfactory organs of fish are located on the sides of the head and resemble small cones. With their help, they can capturechanges in the chemical composition of water. The sense of smell is especially sharply developed in those animals that hunt at night. For example, a pike fish can sniff out prey that swims a few meters away.
Side line. Location
Many scientists believe that the lateral line in fish is the most important sense organ that helps animals to exist more comfortably. The lateral line is a kind of single center that unites all sensitive cells in the body, located in the head or body.
The organ is located throughout the body, starting at the head and ending at the tail. The anatomy of fish, their variety and subspecies determine the location of the lateral line and its color. In one species, it may appear as a bright white line, in others it may appear as a dark, almost black stripe.
More fish have a single lateral line. But there are some species that can boast five or more. The lateral line of a fish can be very noticeable visually, or it can be hidden in the scales and immediately invisible to the human eye. In some fish it is arched, in others it is in the form of small jerky stripes on the head.
There are fish that are deprived of the sixth sense organ. These include mullet, dallium, some fish of the carp-tooth family.
The sideline consists of…
As we have already said, the lateral line of the fish is a kind of brain and nerve center that allows you to control what is happening around. What does this one consist of?center?
The lateral line is a cluster of a number of receptors that are located among themselves at a certain interval. The receptors can be found in channels on the head or recesses that are located on the sides of the body. Most of the receptors are hidden under the skin of the fish. Only a few come to the surface and are hidden in the scales. Reminiscent of open pores on the skin.
Inside the lateral line channel is filled with liquid. Nerve receptors (their sensitive hairs), catching changes, give a signal to this very fluid. Any movement, change in pressure or temperature of the water can set the receptors and, consequently, the water in the channel in motion. The stronger the changes in the habitat of the fish, the more the receptor hairs will deviate, the faster the information will enter the central nervous system.
The meaning of the lateral line in fish
The sixth sense, or lateral line, allows fish to feel the approach of other animals living in the water, much earlier than their sense of sight or smell informs them. The lateral line is able to capture the smallest changes in pressure in the 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 vision is especially high. There are animals that are able to react exclusively to shadow or light, while not noticing movement in the water at all. The lateral line in this case allows you to compensate for underdevelopment or lack of visual or olfactory skills.
Fromthe lateral line often depends on the life of the fish. If it is damaged, then external influences will not be perceived by the animal so brightly. It will stop responding to danger from outside, will not be able to fully hunt, get food, hide from enemies. And will die soon.
Side line and bite
Surely all experienced fishermen know the meaning of the lateral line of a fish. With its help, the fish is able to capture the slightest noise and vibrations in the water. As experts say, a shot, an explosion, an ordinary conversation in raised tones, a hit on the water will immediately “feel” the lateral line. And the fish, therefore, will react, get scared and hide. It is for this reason that 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 should not be created by the fisherman, but by the bait in the water. Experienced anglers say that the bait should not stand in the pond, it must certainly move, making fluctuations in the liquid. Only in this case the fish will smell food with its lateral line and will move in the direction of the hook.
