The Japanese sea lion was an aquatic mammal thought to have become extinct in the 1970s. It was considered to be a subspecies of California sea lion until 2003. They inhabited 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.
Male Japanese sea lions were dark grey and weighed about, reaching lengths of ; these were larger than male California sea lions. Females were significantly smaller at long with a lighter grey colour than the males.
Distribution and habitat
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. Sightings of individual Japanese sea lions still persist in Korea, but these are probably misidentified Steller's sea lions. The only reliable report may have been of an individual shot at Moneron Island in 1949. Old Korean accounts also describe that the sea lion and spotted seal were found in broad area containing the BoHai Sea, the Yellow Sea, and Sea of Japan. The sea lions and seals left relevant place names all over the coast line of Japan, such as Ashika-iwa and Inubosaki because of the similarity of their howls. They usually resided on flat, open, and sandy beaches, but rarely in rocky areas. Their preference was to rest in caves.
Attempted revival
In 2007, the South Korean Ministry of Environment has announced that South and 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 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. The South Korean Ministry of Environment supports the effort because of the symbolism, national concern, the restoration of the ecological system, and possible ecotourism.
Exploitation and extinction
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 oriental 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. Harvest records from Japanese commercial fishermen in the early 1900s show that as many as 3,200 sea lions were harvested at the turn of the century, and overhunting caused harvest numbers to fall drastically to 300 sea lions by 1915 and to a few dozen sea lions by the 1930s. Japanese commercial harvest of Japanese sea lions ended in the 1940s when the species became virtually extinct. 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.
