Lake Biwa

Lake Biwa is Japan's largest freshwater lake, situated entirely within Shiga Prefecture in the central part of Honshu island. It spans a surface area of about 670 square kilometers. Due to its central location, it has historically been a crucial water source and transportation route in Japan.

Lake Biwa is an ancient tectonic lake, meaning it was formed by movements of the Earth's crust rather than by glaciation or volcanic activity. It is often estimated to be over 4 million years old, making it one of the oldest lakes in the world. Its isolated, long-term existence allowed unique species to evolve.

Lake Biwa is home to more than 50 endemic species, meaning they are found nowhere else on Earth. The most famous is the Biwa salmon, a fish that lives entirely in the lake and its tributaries rather than migrating to the ocean. Other endemics include the Biwa catfish and various types of freshwater shellfish and birds.

Yes, Lake Biwa is a vital water resource, providing drinking water to roughly 14 million people in the Kansai region, including the major cities of Kyoto and Osaka. The lake supports extensive agricultural irrigation and local industries. To protect this crucial water supply, strict environmental regulations govern the lake's watershed.