Ladoga seals (Ringed seal): description, habitat

In the lake of the same name live and breed Ladoga seals. It is interesting that this is their only habitat. But seals are a species to which the Ladoga seal belongs - marine animals. How do they manage to exist in fresh water and how did they find themselves in this lake?

About 11,000 years ago, when the ice age ended, the water level changed. Thus, these mammals got into fresh water.

The Ladoga seal. Description

This animal has another name. It is also called ringed seal, because fur has a gray color with dark rings on it. The abdomen is light. The external structure of the Ladoga seal resembles the constitution of its other relatives, it differs from them in its small size. In length it reaches 1.2 meters and weighs 50-80 kilograms. Nerpa looks thick and short. It has practically no neck. Head small and slightly flattened. Powerful rear fins help to move both in water and on land. Hearing and sense of smell are wonderful. Ladoga seals live for about 30-35 years, and growth ends in 10 years.

These mammals feed on small fish and crustaceans, whose body length does not exceed 20 cm. The menu includes perch, roach, smelt and vendace. In total, a day a predator needs 3-4 kilograms of fish. In the summer, when it is time to moult, the Ladoga seals prefer the northern shore of the lake, especially the islands of the Valaam archipelago: Saint, Lembos, Lysias, Krestovy and others. In the warm season they like to arrange rookery on the rocks, their number in one place can reach 600-650 individuals. And in winter they like the southern, western and eastern shores.

Underwater life

Ladoga seal in water, even in cold water, feels better than on land. Its elongated body is specially adapted for active swimming. In addition, it helps her flippers. To freeze does not give a thick layer of subcutaneous fat and that the wool does not get wet. Deftly diving to a depth of 300 meters, the seal can hold breath for 40 minutes. This is possible due to the fact that her body is able to slow down the metabolism, and, therefore, he needs less oxygen. And the vital organs are supplied with blood: head, liver and brain. Endurance of the seal allows it to swim a few tens of kilometers at a speed of 20 km / h.

How to multiply

For mating, these animals choose the cold season - January-March. To the process of procreation they are ready, having reached the age of six. The calf also comes into being also when the snow lies. Usually ringed seals give birth to one baby. He weighs only 4 kilograms, and his body has a length of 0.6 meters. Its fur has a white color, so it is less noticeable to predators: foxes and wolves.

The mother feeds him with milk for 1.5-2 months, her milk is so fat that the newborn adds a day from 1 kilogram. After that, he begins to feed himself. Nerpa likes drifting ice floes. In them she finds lazy and arranges a dwelling for posterity. During pregnancy, she makes several shelters in the ice, they have an access to which they can descend into the water, as well as breathing holes. Exit to the surface of such a "house" is not available, so the cubs are protected from attack by external enemies. When the time comes, they as well as the mother descend through the hole into the water.

Why disappear

In recent years, the Ladoga seal has become an animal whose population is rapidly declining. The Red Book of Russia has already included it in its list. This is mainly due to human extermination. Earlier, 20-30 thousand individuals lived in the Ladoga Lake, and now only 2-3 thousand seals live in it. The skin, fat, meat of this animal is of value, so it is hunted, but not on an industrial scale.

In the 20th century, the extermination of the seal was not controlled, and now the state fish inspection is engaged in this. The fishing limits are set. Destruction of seals is also justified by the fact that it eats valuable fish in the lake. And this despite the fact that scientists have proved that because of a small mouth seal in Lake Ladoga can not eat much prey, and, therefore, the population, for example, salmon has decreased not because of it. Opponents argue that these mammals eat fish that are entangled in the net, as they do not need to swallow it, but only tear it apart, which they sometimes do for fun.

Additional factors

The Ladoga seals are also dying because they are entangled in strong networks established to fish, of which they can not escape by themselves. In addition, the very fact of the presence of a person on the lake makes them uncomfortable and makes you worry that it also does not contribute to an increase in their numbers. Another factor that affects the decrease in the number of Ladoga seals is the pollution of the lake by sewage. After it began to get waste, these mammals became more sick, they lost their immunity. Lake Ladoga can soon survive an ecological catastrophe.

Is not it time to stop?

Discharge of harmful substances, toxic compounds, salts of heavy metals in the lake has been carried out for several years. In addition, polluted atmospheric precipitation enters the water. At the bottom of Lake Ladoga, there are areas where invertebrates do not live. Some fish were on the verge of extinction, for example, the Atlantic sturgeon listed in the Red Book . And this means a reduction in nutrition for the seal and a gradual extinction from hunger. Also bad for these animals and warming, and, hence, a decrease in the snow cover. After all, they need ice floes, if only in order to hide the cubs and hide themselves.

Measures taken

Biologists interested in saving the life of the Ladoga seal have created a service for rescuing pinnipeds in the village of Repino, Leningrad Region. This is the first such organization in Russia. Scientists use their experience and accumulated knowledge to help such mammals. Not only the Ladoga seal can be under the supervision of the center, but any of its relatives who are in trouble. In the winter, it is pinnipeds with broken thermoregulation. For them, the heating station works. Animals can live here for a while. Individual boxes are equipped for them. Staff lives in a place specially designed for him. Separately prepare food for animals. To accelerate the adaptation of pinnipeds, a swimming pool was built.

People are aware of the problem of possible extinction and are struggling to save the seal. Limit visits to areas where seals rest, reduce fishing in the lake. Although it is impossible to prohibit people from admiring the rare species of animals in natural habitats. The main thing is to remember that in order to survive, the Ladoga seal requires not a person's increased attention, but a reasonable approach to solving the issue of joint existence on this planet.