The world of fish is amazing and has not yet been fully studied, a person is constantly discovering new species, discoveries are being made. However, the question remains whether the fish experience pain, whether they are capable of it. The study of the internal structure of the body of these aquatic inhabitants will help to answer it.
Features of the nervous system
The nervous system of fish has a complex structure and is divided into:
- central (which includes the spinal cord and brain);
- peripheral (which is composed of nerve cells and fibers);
- vegetative (nerves and ganglia supplying internal organs with nerves).
At the same time, the system is much more primitive than that of animals and birds, but it significantly surpasses the organization of non-cranial 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 essential functions:
- coordinates movements;
- responsible for the perception of sounds and taste sensations;
- brain centers control the activity of the digestive, circulatory, excretory and respiratorysystems;
- thanks to a highly developed cerebellum, many fish, such as sharks, can reach 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 CNS is an expanding part of the anterior neural tube and includes three main sections, the characteristics of which are presented in the table.
| Brain section | Features |
| Front | Responsible for the sense of smell, consists of telencephalon (terminal) and diencephalon (intermediate). |
| Medium | Responsible for vision and swimming movements, contains the optic nerves and the tire. |
| Rear | It has a complex structure, including the bridge, the elongated brain and the cerebellum. The latter helps the fish to maintain balance. |
The brain of fish is very primitive: it is small (less than 1% of body weight), its most important parts, such as the forebrain, are very poorly developed. At the same time, each class of fish is characterized by its own features of the structure of the brain regions.
The clearest differentiation can be seen in sharks, which have well-developed sense organs.
Interestingly, at 19 -At the beginning of the 20th century, scientists believed that aquatic inhabitants were primitive and were not able to perceive either sounds or tastes, but subsequent research on fish disproved these assumptions. It has been proven that these creatures use the senses and are able to navigate in space.
Spinal cord
It is located inside the vertebrae, namely, inside their neural arches, in the spinal canal. Its appearance resembles a thin lace. It is he who regulates almost all body functions.
Pain sensitivity
Many are interested in the question - do fish feel pain. The features of the structure of the nervous system presented above will help to understand. Some modern studies give an unambiguous negative answer. The arguments are:
- No pain receptors.
- The brain is underdeveloped and primitive.
- The nervous system, although it has stepped forward from the level of invertebrates, still does not differ in particular complexity, and therefore cannot fix pain sensations and differentiate them from all others.
This is the position taken by Jim Rose, a fish researcher from Germany. Together with a group of colleagues, he proved that fish can react to physical stimuli, such as contact with a fishhook, but they are not able to experience pain. His experiment was as follows: the fish was caught and released, after a couple of hours (and some species immediately), she returned to her usual life, without retaining pain in her memory. Forfish are characterized by defensive reactions, and a change in its behavior, for example, when it hits a hook, was explained not by pain, but by stress.
Other position
In the scientific world, there is another answer to the question of whether fish feel pain. Victoria Braithwaite, a professor at the University of Pennsylvania, also conducted her research and made sure that the nerve fibers of 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 compassion.
The Dutch researchers adhere to the same position: they believe that a fish caught on a hook is subject to both pain and fear. The Dutch conducted a cruel experiment with trout: they exposed the fish to several irritants, injected it with bee venom and observed the behavior. The fish tried to get rid of the substance affecting it, rubbed against the walls of the aquarium and stones, swayed. All this made it possible to prove that she still feels pain.
It was found that the strength of the pain experienced by the fish depends on temperature. Simply put, a creature caught in winter suffers much less than a fish hooked on a hot summer day.
Modern research has revealed that the answer to the question of whether a fish feels pain cannot be unambiguous. Some scientists claim that they simply cannot do this, while others argue that marine inhabitantssuffer from pain. In view of this, one should treat these living beings with care.
Long-lived fish
Many are interested in the question of how long fish live. It depends on the specific species: for example, science knows creatures whose life is only a few weeks. There are real centenarians among marine life:
- Belugas can live up to 100 years;
- Kaluga, also a representative of sturgeons, - up to 60 years old;
- Siberian sturgeon - 65 years old;
- Atlantic sturgeon is the absolute record holder, recorded cases of life in 150 years;
- catfish, pike, eels and carps can live for more than 8 decades.
The Guinness World Record holder is a 228-year-old female mirror carp.
Science also knows species with a very short lifespan: these are anchovies and small-sized inhabitants of the tropics. Therefore, the answer to the question of how long fish live cannot be unambiguous, it all depends on the specific species.
Science pays due attention to the study of aquatic inhabitants, but many aspects still remain unexplored. Therefore, it is very important to understand that it is possible that researchers will very soon answer positively the question of whether fish feel pain. But in any case, these living beings must be treated with care and caution.
