Lake Baikal is the oldest lake in the world where trenches were isolated and formed about 30 million years ago. At that time, it cultivated a wide variety of aquatic organisms left behind from the sea to adapt to desalination. Two-thirds of about 1,500 species are regarded as endemic species, also called "Russian Galapagos". The representative is a sturgeon. It is the Baikal seal that reigns at the top of the rich ecosystem. It is said to be dense gray brown, small seal of about 100 cm in length, with big eyes and superb dive ability to find prey in deep water of Baikal Lake, and it dives for dozens of minutes continuously. Baikal Lake has a beautiful and rich ecosystem, but water quality is deteriorating due to domestic wastewater and industrial wastewater. As a result, the destruction of ecosystems, such as the reduction of endemic species, is proceeding. Sustainable development is required to survive these valuable creatures.