Ladoga seals live and breed in the lake of the same name. Interestingly, this is their only habitat. But seals - the species to which the Ladoga seal belongs - are marine animals. How do they manage to exist in a fresh water body and how did they end up in this lake?
About 11,000 years ago, when the ice age ended, the water level changed. This is how these mammals ended up in fresh water.
Ladoga seal. Description
This animal has another name. It is also called the ringed seal because the fur is gray in 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. It reaches 1.2 meters in length and weighs 50-80 kilograms. The seal looks thick and short. She has practically no neck. The head is small and slightly flattened. Powerful rear flippers help move both in water and on land. Her hearing and sense of smell are excellent. Ladoga seals live for about 30-35 years, andgrowth ends at age 10.
These mammals feed on small fish and crustaceans, the body length of which does not exceed 20 cm. The menu includes perch, roach, smelt and vendace. In total, this predator needs 3-4 kilograms of fish per day. In summer, when the time of molting comes, the Ladoga seals prefer the northern shore of the lake, especially the islands of the Valaam archipelago: Saint, Lembos, Lisiy, Krestovy and others. In the warm season, they like to arrange a 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 the water, even in the cold, feels better than on land. Its elongated body is specially adapted for active swimming. In addition, fins help her in this. Freeze does not give a thick layer of subcutaneous fat and the fact that the wool does not get wet. Deftly diving to a depth of 300 meters, the seal can hold its breath for 40 minutes. This is possible due to the fact that her body is able to slow down the metabolism, and, therefore, it needs less oxygen. Moreover, vital organs are intensively supplied with blood: the head, liver and brain. The endurance of the seal allows it to swim several tens of kilometers at a speed of 20 km/h.
How to breed
For mating, these animals choose the cold season - January-March. They are ready for the process of childbearing, having reached the age of 6. The cub is also born when there is snow. Ringed seals usually give birth to one baby. He weighs only4 kilograms, and his body has a length of 0.6 meters. Its fur is white, so it is less visible to predators: foxes and wolves.
Mother feeds him with milk for 1, 5-2 months, her milk is so fatty that the newborn adds 1 kilogram per day. After that, he begins to eat on his own. The seal is very fond of drifting ice floes. In them she finds manholes and arranges a dwelling for posterity. During pregnancy, she makes several shelters in the ice, they have a hole through which you can go down into the water, as well as holes for breathing. Such a “house” does not have access to the surface, so the cubs are protected from attack by external enemies. When the time comes, they, like their mother, go down the hole into the water.
Why disappear
In recent years, the Ladoga seal has also 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. Previously, 20-30 thousand individuals lived in Lake Ladoga, and now only 2-3 thousand seals live in it. The skin, lard, and meat of this animal are valuable, so they are hunted, but not on an industrial scale.
In the 20th century, the extermination of seals was not controlled, and today the state fish inspection is engaged in this. Fishing limits have been set. The destruction of the seal is also justified by the fact that it eats valuable species of fish in the lake. And this is despite the fact that scientists have proven that because of the small mouth, the seal in Lake Ladoga cannot eat a largeprey, which means that the population of, for example, salmon has not decreased because of it. Opponents claim that these mammals eat fish tangled in the net, since they do not need to swallow it, but only tear it off piece by piece, which they sometimes do for fun.
Additional factors
Ladoga seals also die because they get entangled in strong nets set up to catch fish, from which they cannot get out on their own. In addition, the very fact of the presence of a person on the lake gives them inconvenience and makes them worry, which also does not contribute to an increase in their numbers. Another factor influencing the decrease in the number of Ladoga seals is the pollution of the lake with sewage. After waste began to get into it, these mammals began to get sick more often, their immunity decreased. Lake Ladoga may soon survive an ecological catastrophe.
Is it time to stop?
Harmful substances, toxic compounds, s alts of heavy metals have been dumped into the lake for several years. In addition, polluted precipitation enters the water. At the bottom of Lake Ladoga, areas were found 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 food for seals and a gradual extinction from hunger. Warming also has a bad effect on these animals, and, therefore, a decrease in snow cover. After all, they need ice floes, at least in order to have somewhere to hide the cubs and take cover.by yourself.
Action taken
Biologists interested in saving the life of the Ladoga seal have created a rescue service for 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, but any of its relatives who are in trouble can find themselves under the supervision of the center. In winter, these are pinnipeds with impaired thermoregulation. There is a special heating station for them. Animals can live here for a while. They are equipped with individual boxes. The staff lives in a place specially designed for them. Separately prepare food for animals. A swimming pool was built to speed up the adaptation of pinnipeds.
People are aware of the problem of possible extinction and are fighting to save the seal. Restrict visits to areas where seals rest, reduce fishing in the lake. Although it is impossible to forbid people to admire a rare species of animals in their natural habitat. The main thing to remember is that in order to survive, the Ladoga seal does not need increased human attention, but a reasonable approach to resolving the issue of coexistence on this planet.
