If you are fond of biology, then for sureyou know how to determine the age of some species of animals and plants. So, in cattle age can be recognized by the horns: each lived year leaves the ring. In a similar way, you can find out the age of a tree. Having looked at the number of annual rings on its cut, you can, within a couple of years, find out how many years ago it grew. But how do you know the age of a fish? This is especially interesting for fishermen, who occasionally catch spectacular specimens.
The fact is that the scales form the sameannual rings, which can be seen on the sprees of trees or horns of cows. By the width of the ring you can find out about what the year was, if there was enough food for the fish. The wider the ring, the more favorable conditions were at that time. However, before you know the age of the fish, it is worth knowing what scales to take. Scales from the middle part of the lateral line are ideal. Before determining the age, it should be dried properly and counted under the magnifying glass.
However, how to know the age of river fish, on the bodywhich does not have scales? These include burbot and sterlet. In addition, in such species as the ruff, perch, or pike, the scales are so small that they can only be examined under a microscope, and in this case it is no wonder that mistakes are made. To solve such a problem it is necessary to resort to the help of another method.
So, perch for age determinationThe dried gill cover is used, for vertebrae years are considered in ruff or burbot. In a noble white fish, you can find out the age by the spicules of the rays of the anterior vertebrae, and you also need to dry them properly beforehand. But how do you know the age of a fish in this case? Everything is simple: the above parts of the body after drying, you need to saw, and on the cut will be clearly visible all the same year rings, which you need to navigate, determining the age of the fish.
Do not assume that the methods we have describedare good only for freshwater fish. They are also suitable for marine fauna, which often does not have scales or is too small. Those who are thinking about how to know the age of sea fish, remember that to count its annual rings may take a long time. So, a few years ago near Alaska a grouper was caught, the age of which was estimated by biologists as much as 200 years!
However, according to a number of researchers, morerecently in our rivers it was possible to catch soms of even more respectable age. Some scientists believe that a number of deep-sea fish live almost forever, dying only from the action of elements or attacks of predators.</ p>