Shiretoko Peninsula

The Shiretoko Peninsula juts out from the easternmost part of Hokkaido, Japan, into the Sea of Okhotsk. The Nemuro Strait separates it from Kunashiri Island. Its name comes from the Ainu phrase *sir etok*, meaning "the end of the Earth" or "the place where the Earth protrudes." The peninsula contains the towns of Rausu and Shari. 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, part of the Chishima volcanic zone, runs from Shiretoko Cape at the tip down the peninsula, including Mount Shiretoko, Mount Unabetsu, and Mount Iō. Mount Rausu is the highest peak. The Sea of Okhotsk borders the northwest side, while the Pacific Ocean lies to the southeast. Kunashiri Island, visible from the peninsula, runs parallel to it to the east; Russia has occupied the island since September 1, 1945, and Japan disputes this. The cold Oyashio Current flows southwest along the east side, and the Soya Current flows southeast from the Sea of Okhotsk before turning north along the west side. In winter, the Soya Current carries sea ice south, where it dams against the west coast, creating the lowest-latitude regular sea ice on Earth at 43 degrees north. The volcanic zone supports several hot springs, such as Seseki Onsen and Iwaobetsu Onsen.

The peninsula’s peaks include Mount Poromoi, Mount Shiretoko, Mount Dokkarimui, Mount Rusha, Mount Higashi, Mount Chienbetsu, Mount Minami, Mount Iō, Mount Okkabake, Mount Sashirui, Mount Rausu, Mount Chinishibetsu, Mount Onnebetsu, Mount Unabetsu, Mount Shari, Mount Samakke Nupuri, and Mount Shibetsu.

The Oyashio Current heavily influences 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, except for the highest ones, which keep 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; the wreck was found 100 meters deep near Kashuni Falls. Fourteen bodies were recovered, and twelve people remain missing.

The peninsula hosts many conifer and broadleaf tree species, 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 reaches of Mount Rausu, Mount Onnebetsu, and Mount Shari are the only known breeding areas 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 is popular; thirteen or fourteen cetacean species have been recorded. The waters around the peninsula are a key habitat for orcas in the northwestern Pacific. A notable mass stranding of twelve orcas occurred in February 2005, killing nine. In 2019 and 2021, several white orcas were sighted. The area is one of the few places where groups of male sperm whales and beaked whales, including Baird’s beaked whales, can be seen from shore. Other common 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. Beluga whales, likely vagrants from the endangered northern Sea of Okhotsk population, appear occasionally; a sub-adult individual frequented the town of Shibetsu for several years in the 2000s. North Pacific right whales, the most endangered great whale, have been sighted close to shore on the Sea of Okhotsk side in 2013, 2018, and 2019, with several sightings in 2013 and 2019; the 2018 sighting and one from 2019 were made by the same tour operator, Doutou Kanko Kaihatsu. From June 21 to 23, 2015, the first bowhead whale ever seen in Japan’s exclusive economic zone was recorded (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, though they rarely enter these seas and are now nearly extinct in Japanese waters. The deep, productive waters attract beaked whales such as Cuvier’s and Stejneger’s beaked whales; Baird’s beaked whales are the most frequently seen from shore. An unidentified form or subspecies of beaked whale also lives off the peninsula and Abashiri. Long-finned pilot whales that once lived around Hokkaido are thought to have gone extinct in the 12th century, but unconfirmed sightings of short-finned pilot whales have been reported in Nemuro Strait, though the area is outside their normal range.