Shiretoko Peninsula

Shiretoko Peninsula juts out from the easternmost tip of Hokkaido into the Sea of Okhotsk. The Nemuro Strait separates it from Kunashiri Island, which lies to the east and is visible from the peninsula. Its name comes from the Ainu phrase *sir etok*, meaning "the end of the Earth" or "the place where the Earth protrudes." The towns of Rausu and Shari sit on the peninsula. In 2005, UNESCO designated it a World Heritage Site because it is the southernmost place in the Northern Hemisphere where sea ice regularly forms.

The peninsula stretches 70 kilometers long and 25 kilometers wide at its base, covering about 123,000 hectares. A chain of volcanoes—including Mount Shiretoko, Mount Unabetsu, and Mount Iō—runs from Shiretoko Cape at the tip down the peninsula, part of the Chishima volcanic zone. The highest peak is Mount Rausu. The Sea of Okhotsk borders the northwest side, and the Pacific Ocean borders the southeast. The cold Oyashio Current flows southwest along the east coast, while the Soya Current moves southeast from the Sea of Okhotsk before turning north along the west side. In winter, the Soya Current carries sea ice south, which dams against the peninsula’s west coast, creating the lowest-latitude regular sea ice on Earth at 43 degrees north. The volcanic activity supports several hot springs, such as Seseki Onsen and Iwaobetsu Onsen.

The Oyashio Current heavily shapes the climate, bringing short summers and long winters. It causes fog on the southeastern coast and sea ice in winter. Snow covers the peaks from September to June, with the highest summits retaining snow all summer. The strong subarctic current makes boat navigation difficult. On April 23, 2022, a 19-ton tourist boat carrying 26 people sank during a tour near the peninsula; it was found 100 meters below sea level near Kashuni Falls. Fourteen bodies were recovered, and twelve people remain missing.

The peninsula hosts a mix of conifers and broadleaf trees, including the acorn-bearing *Quercus mongolica* (mizunara). Siberian dwarf pine grows above 1,000 meters. Red foxes and sika deer live here, along with a large population of Ussuri brown bears. The upper slopes of Mount Rausu, Mount Onnebetsu, and Mount Shari are the only known breeding sites in Hokkaido for Arctic warblers. Sea eagles thrive, and seals are common along the coast. The last confirmed record of the Japanese otter in Hokkaido came from the Shari River.

Whale watching draws many visitors. Thirteen or fourteen cetacean species have been recorded in the area. The waters around the peninsula are considered a key habitat for orcas in the northwestern Pacific. A notable mass stranding of twelve orcas occurred in February 2005, killing nine. In 2019, two white orcas were sighted, and several white individuals were seen in 2019 and 2021. The peninsula is one of the few places where male sperm whales and beaked whales—including Baird’s beaked whales—can be seen from shore. Other frequently spotted species include minke whales, Pacific white-sided dolphins, Dall’s porpoises, and harbor porpoises. The newly described Sato’s beaked whale also inhabits the area. Endangered humpback and fin whale populations in the Sea of Okhotsk have begun recovering in recent years. Beluga whales, likely vagrants from the endangered northern Sea of Okhotsk population, occasionally appear; a sub-adult individual was seen near Shibetsu for several years in the 2000s. North Pacific right whales, the most endangered great whale, have been observed close to shore on the Sea of Okhotsk side in 2013, 2018, and 2019, with multiple sightings in 2013 and 2019; the 2018 sighting and one in 2019 were made by the same tour operator, Doutou Kanko Kaihatsu. From June 21 to 23, 2015, the first bowhead whale sighting in Japan’s exclusive economic zone occurred (the only previous national record was a catch in Osaka Bay on June 23, 1969). Whaling records show blue whales were once harpooned and landed at Abashiri port, but this species rarely enters adjacent seas and is now nearly extinct in Japanese waters. The deep, productive waters attract several beaked whale species, including Cuvier’s and Stejneger’s beaked whales. Baird’s beaked whales are the most frequently seen close to shore. An unidentified form or subspecies of beaked whale also inhabits the waters off Shiretoko and Abashiri. Long-finned pilot whales, which once lived around Hokkaido, are thought to have gone extinct in the 12th century, though unconfirmed sightings of short-finned pilot whales have been reported in Nemuro Strait, outside their normal range.