The Korea Strait is composed of the Western Channel and the Tsushima Strait, on either side of Tsushima Island. The straits were formed in recent geologic periods. The oldest of them are the Tsugaru and Tsushima straits. Their formation had interrupted the migration of elephants into the Japanese islands at the end of the Neogene Period (about 2.6 million years ago). The most recent is La Perouse Strait, which formed about 60,000 to 11,000 years ago closing the path used by mammoths which had earlier moved to northern Hokkaidō. All the straits are rather shallow, with a minimal depth of the order of 100 meters or less. This hinders water exchange, thereby isolating the water and aquatic life of the Sea of Japan from the neighboring seas and oceans.
The Korea Strait is composed of the Western Channel and the Tsushima Strait, on either side of Tsushima Island. The straits were formed in recent geologic periods. The oldest of them are the Tsugaru and Tsushima straits. Their formation had interrupted the migration of elephants into the Japanese islands at the end of the Neogene Period (about 2.6 million years ago). The most recent is La Perouse Strait, which formed about 60,000 to 11000 years ago closing the path used by mammoths which had earlier moved to northern Hokkaidō. All the straits are rather shallow, with a minimal depth of the order of 100 meters or less. This hinders water exchange, thereby isolating the water and aquatic life of the Sea of Japan from the neighboring seas and oceans.