Full winter has finally descended upon eastern Hokkaido’s Shiretoko Peninsula. If you follow the Shiretoko Mountain Range with your eyes down to the ocean, you will see a black mass floating on the waters of Rausu. This is a group of Steller sea lions.
The Steller sea lions that migrate eastern Hokkaido’s Nemuro Strait in winter migrate from their breeding area in the central Kuril Islands. Groups of a dozen or so sea lions are mainly made up of females. There are not many males, and the groups mainly consist of children and young sea lions that cannot yet participate in mating. There are almost no adults.
Because Steller sea lions prefer the coast area with its shallow depths to the farther out offing waters, they can be seen basking in the sun on the water surface at the Rausu Town coast from December through January of the next year. They start coming south before drift ice flows in, and disappear when Nemuro Strait becomes covered in drift ice. You would not imagine it from their appearance, but underwater they swim lithely, catching fish and eating them.
In April, when the drift ice disappears from Rausu, Steller sea lions are sometimes seen near the tip of the Shiretoko Peninsula. However, they gradually return to their breeding area together with northward flow of the drift ice.