Японский морской лев: исчезнувший вид из Восточной Азии

Extinct species of sea lion from East Asia

The Japanese sea lion (Zalophus japonicus) (ニホンアシカ, hangul=강치, 바다사자) was an aquatic mammal that became extinct in the 1970s. It was considered to be a subspecies of the related California sea lion (Z. californianus) until 2003. They inhabited the western North Pacific and its marginal seas including the Sea of Okhotsk and the Sea of Japan, especially around the coastal areas of the Japanese Archipelago and the Korean Peninsula. They generally bred on sandy beaches which were open and flat, but sometimes in rocky areas. They were hunted commercially in the 1900s, leading to their extinction.

Prior to 2003, it was considered to be a subspecies of California sea lion as Zalophus californianus japonicus. However, it was subsequently reclassified as a separate species. Several taxidermied specimens can be found in Japan and in the National Museum of Natural History, Leiden, the Netherlands, bought by Philipp Franz von Siebold. The British Museum possesses a pelt and four skull specimens.

Male Japanese sea lions were dark grey, reaching lengths of and weighed about Females were significantly smaller at long and weighed about with a lighter grey colour than the males.

Japanese sea lions were found along the northwest Pacific coastline, specifically in Japan, Korea, southern Kamchatka Peninsula, and the Sakhalin Island. However, they may not have existed in Kamchatka, with their northernmost range extending only to the Kuril Islands. The only reliable report may have been of an individual shot at Moneron Island in 1949. The sea lions and seals left relevant place names all over the coast line of Japan, such as Ashika iwa (海驢岩 or 海鹿岩, sea lion rock) and Ashika jima (海獺島 or 海鹿島, sea lion island), and Cape Inubō (犬吠埼, dog barking point) because of their howls to compared to dog's barking. Bones of Z. japonicus dating to 3500–2000 BC were found in the Shell Mound in Dongsam dong, Busan. Genetic evidence confirms the former presence of Z. japonicus on the Liancourt rocks. They usually resided on flat, open, and sandy beaches, but rarely in rocky areas. Their preference was to rest in caves.

Many bones of the Japanese sea lion have been excavated from shell middens from the Jōmon period in Japan while an 18th century encyclopedia, Wakan Sansai Zue, describes that the meat was not tasty and they were only used to render oil for oil lamps. Valuable oil was extracted from the skin, its internal organs were used to make expensive medicine, and its whiskers and skin were used as pipe cleaners and leather goods, respectively. At the turn of the 20th century, they were captured for use in circuses. In total, Japanese trawlers harvested as many as 16,500 sea lions, enough to cause their extinction. Submarine warfare during World War II is even believed to have contributed to their habitat destruction. The most recent sightings of Z. japonicus are from the 1970s, with the last confirmed record being a juvenile specimen captured in 1974 off the coast of Rebun Island, northern Hokkaido. There were a few unconfirmed sightings in 1983 and 1985. The last credible documentation was made in 1951 on the Liancourt Rocks reporting 50 to 60 animals. In any case, it was one of the most recent marine mammal extinctions to occur, alongside the Caribbean monk seal which went extinct at around the same time.

In 2007, the South Korean Ministry of Environment announced that South Korea, North Korea, Russia, and China will collaborate on bringing back sea lions to the Sea of Japan, starting with a search for any Japanese sea lions that might still be alive. The National Institute of Environmental Research of South Korea was commissioned to conduct feasibility research for this project. If the animal cannot be found, the South Korean government plans to relocate California sea lions from the United States. and on Koshikijima Islands in March, 2016. Both animals were positively identified as Otariidae based on photographs, but their identities are unclear.