Do fish feel pain? Nervous system and fish brain

The world of fish is amazing and so far not fully understood, a person constantly opens up new species, discoveries are made. However, the question remains - are the fish experiencing pain, are they capable of this. The answer to it will help the study of the internal structure of the body of these aquatic inhabitants.

Features of the nervous system

The nervous system of fish has a complex structure and is divided into:

• central (including the spinal cord and brain);
• peripheral (which are composed of nerve cells and fibers);
• autonomic (nerves and ganglia supplying the internal organs with nerves).

At the same time, the system is much more primitive than that of animals and birds, however, it significantly exceeds the organization of disembodied ones. The autonomic nervous system is rather poorly developed, it consists of several ganglia scattered along the spinal column.

The central nervous system of fish performs the following critical functions:

• coordinates movements;
• responsible for the perception of sounds and taste sensations;
• brain centers control the digestive, circulatory, excretory and respiratory systems;
• thanks to the highly developed cerebellum, many fish, such as sharks, can develop high speeds.

It is located along the body: under the protection of the vertebrae is the spinal cord, under the skull of bones or cartilage - the head.

Fish brain

This component of the central nervous system is an expanding part of the anterior neural tube and includes three main departments, the characteristics of which are presented in the table.

The fish brain is very primitive: it has a small size (less than 1% of body weight), its most important departments, for example, the forebrain, are very poorly developed. At the same time, each class of fish is characterized by its own characteristics of the structure of the brain departments.

The most distinct differentiation can be seen in sharks, characterized by well-developed sensory organs.

It is interesting that in the 19th and early 20th centuries, scientists believed that water inhabitants are primitive and are not able to perceive neither sounds nor tastes, but a subsequent study of fish refuted these assumptions. It was proved that these creatures use the senses and are able to navigate in space.

Spinal cord

It is located inside the vertebrae, namely, inside their nerve arches, in the spinal canal. Its appearance resembles a thin lace. It is he who regulates almost all the functions of the body.

Pain sensitivity

Many are interested in the question - do fish feel pain. The features of the device of the nervous system presented above will help to understand. Some modern studies give a clear negative answer. The arguments are as follows:

• Lack of pain receptors.
• The brain is underdeveloped and is primitive.
• Although the nervous system has stepped forward from the level of invertebrates, it still does not differ in particular complexity, and therefore cannot fix pain and differentiate it from all others.

This is the position Jim Rose, a fish explorer from Germany, takes. Together with a group of colleagues, he proved that fish can show a reaction to physical effects, for example, to contact with a fish hook, but it is not able to experience pain. His experiment was as follows: the fish were caught and released, after a couple of hours (and some species immediately), it returned to its usual life activity, without remembering the pain. Defensive reactions are characteristic of fish, and a change in its behavior, for example, when hit by a hook, was explained not by pain, but by stress.

Other position

In the scientific world, there is another answer to the question whether the fish feel pain. Victoria Braithwaite, a professor at the University of Pennsylvania, also conducted her research and made sure that the nerve fibers of the fish are in no way inferior to the same processes in birds and animals. Therefore, marine inhabitants are able to feel suffering and pain when they are caught, cleaned or killed. Victoria herself does not eat fish and advises everyone to treat them with sympathy.

Dutch researchers hold the same position: they believe that fish caught on a hook are subject to both pain and fear. The Netherlands conducted a cruel experiment with trout: they acted on the fish with several irritants, injected bee venom to it and observed the behavior. The fish tried to get rid of the substance acting on it, rubbed against the walls of the aquarium and stones, swayed. All this allowed to prove that she still feels pain.

It was found that the strength of the pain sensation experienced by the fish depends on temperature. Simply put, a creature caught in winter suffers much less than a fish caught on a hook on a hot summer day.

Modern research has revealed that the answer to the question of whether the fish feel pain can not be unequivocal. Some scientists claim that they simply cannot do this, while others argue that marine inhabitants suffer from pain. In view of this, these living beings should be treated with care.

Centenarial fish

Many are interested in how many fish live. It depends on the particular species: for example, science knows the creatures whose life is only a few weeks. Among the marine inhabitants, there are real centenarians:

• Beluga can survive up to 100 years;
• Kaluga, also a representative of sturgeons, up to 60 years old;
• Siberian sturgeon - 65 years old;
• Atlantic sturgeon is an absolute record holder; life cases of 150 years have been recorded;
• catfish, pike, eels and carp are able to live more than 8 decades.

The record holder, listed in the Guinness Book of Records, is a female carp carp, whose age is 228 years.

Species with a very short life expectancy are also known to science: these are hamsa and small in size inhabitants of the tropics. Therefore, the answer to the question of how much fish live cannot be unambiguous, it all depends on the particular species.

Science pays due attention to the study of water inhabitants, but many aspects are still unlit. Therefore, it is very important to understand that it is possible that researchers will very soon respond positively to the question of whether the fish feel pain. But in any case, these living beings must be treated with care and caution.