Japanese Sea Lion
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| Japanese Sea Lion | ||||||||||||||||
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| Zalophus japonicus (Peters, 1866) |
Japanese Sea Lion (Zalophus japonicus) is thought to have become extinct in the 1950s.[1][2]
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.[1] Some taxonomists still consider it as a subspecies of the California Sea Lion. It has been argued that japonicus, californianus, and wollenbaeki are distinct species because of their distant habitation areas and behavioral differences.
They inhabited the Sea of Japan, especially around the coastal areas of the Japanese Archipelago[3] and the Korean Peninsula.[4] They generally bred on sandy beaches which were open and flat, but sometimes in rocky areas.
Currently, several stuffed specimens can be found in Japan[5] and the National Museum of Natural History, Leiden, the Netherlands brought by Philipp Franz von Siebold.[3] The British Museum possesses a pelt and 4 skull specimens.[3]
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[edit] Physical description
Male Japanese Sea Lions were dark grey and weighed up to 450 to 560 kg reaching lengths of 2.3 to 2.5 meters; these were larger than male California Sea Lions. Females were significantly smaller at 1.64 meters long with a lighter colour than the males.[2]
[edit] Range and habitat
Japanese Sea Lions were primarily found in the Sea of Japan along the coastal areas of the Korean Peninsula, the mainlands of the Japanese Archipelago (the both sides on the Pacific Ocean and Sea of Japan), the Kuril islands, and southern tip of the Kamchatka Peninsula.[2][6]
Old Korean accounts also describe that the sea lion and Spotted Seal (Phoca largha) were found in broad area containing the Bo Hai, the Yellow Sea, and Sea of Japan.[4] The sea lions and seals left a lot of relevant place names all over the coast line of Japan such as Ashika-iwa (アシカ岩, sea lion rock) and Inubosaki point (犬吠崎, lit. dog-barking point) because of the similarity of their howls.
[edit] Lifestyle and reproduction
They usually bred on flat, open and sandy beaches but rarely in rocky areas. Their preference was to rest in caves.[7]
[edit] Human uses
Many bones of Japanese Sea Lion have been excavated from shell middens in Jōmon period in Japan[8][9][10] while an 18th century's encyclopedia, Wakan Sansai Zue describes that the meat was not tasty and they were only used to render oil for oil lamps.[11] Valuable oil was extracted from the skin, its internal organs were used to make expensive oriental medicine, and its whiskers and leathers were used as pipe cleaners and leather goods, respectively. Later, they were captured for use in circuses.[1]
[edit] Japanese Fishery
In 1903, Nakai Yōzaburō, a Japanese businessman, built a fishery house on the uninhabited Liancourt Rocks to aid in harvesting sea lions and subsequently, until Japan's involvement in World War II in 1941, the hunting of sea lions in this location was subject to government approval.[12] A former fisherman of the Oki Islands stated that they worked to protect the sea lion population to ensure perpetuity of the resource before WWII.[13]
[edit] Extinction
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 overfishing caused harvest numbers to fall drastically to 300 sea lions by 1915 and to few dozen sea lions by the 1930s. Commercial harvest of Japanese sea lions ended in the 1940s when the species became virtually extinct[14]. In total, Japanese trawlers harvested as many as 16,500 sea lions, enough to cause their extinction, it is even believed that submarine warfare during World War II contributed to their habitat destruction.[15][16] The last colony of sea lions was allegedly sighted by Korean coast guards in the 1950s[15] and the last confirmed record of a Z. japonicus in Japan was a juvenile, captured in 1974 off the coast of Rebun Island, northern Hokkaido. Other unconfirmed sightings exist but it is possible these were, however, escaped Z. californianus seals.
[edit] Population Revival Efforts
The South Korean Ministry of Environment initiated an effort to search for and reintroduce sea lions to their native habitat. The National Institute of Environmental Research of Korea was commissioned to conduct feasibility research for this project.[17] In 2007, a joint research venture between North Korea, South Korea, Russia, and China was announced. Chinese and Russian waters will be searched for surviving sea lion populations, with hopes of reintroducing the animal to the coast of Sea of Japan.[15] If the animal cannot be found, the South Korean government plans to relocate California sea lions from the United States.[16] The South Korean Ministry of Environment supports the effort because of the symbolism, national concern, the restoration of the ecological system, and possible ecotourism.[15]
[edit] References
- ^ a b c "2007 IUCN Red List (EX) Zalophus japonicus", World Conservation Union. Retrieved on 2007-09-21. "There have been no documented reports of Z. japonicus since the late 1950s. The last credible report was 50 to 60 individuals on Takeshima in 1951 (Rice 1998). Individual sightings reported as recently as 1974 and 1975, cannot be confirmed as confusion with escaped Z. californianus cannot be ruled out."
- ^ a b c (Japanese) Zalophus californianus japonicus (CR), Red Data Book, Japan Integrated Biodiversity Information System, Ministry of the Environment (Japan). "The Japanese sea lion (Zalophus californianus japonicus) was common in the past around the coast of the Japanese Archipelago, but declined rapidly after 1930's from overhunting and increased competition with commercial fisheries. The last record in Japan was a juvenile, captured in 1974 at off the coast of Rebun Island, northern Hokkaido."
- ^ a b c (Japanese) "ニホンアシカ剥製標本", the ReCCLE (Research Center for Coastal Lagoon Environments) Museum, Shimane University, Japan.
- ^ a b (Japanese) (en abstract available) Itoo Tetsuro, Fujita Akiyoshi, Kubo Kin-ya, "Pinniped records on the neighbouring waters of the Korean Peninsula: Japanese sea lions and larga seals recorded in the ancient literature of Korea", 野生生物保護 (Wildlife conservation Japan),Vol.6, No.2 (20010731), 51-66, Wildlife Conservation Society ISSN 13418777.
- ^ (Japanese) "天王寺動物園で「絶滅の危機にある動物展」を開催します", Tennoji Zoo, Osaka, Japan.
- ^ Zalophus californianus japonicus (EX), Red Data Book Tottori (mammals), Tottori Prefecture, Japan, p. 34.
- ^ (Japanese) Zalophus californianus japonicus (EX), Shimane Red Data Book 2004, Shimane Prefecture, Japan.
- ^ The Jomon people in the northern Island, National Museum of Japanese History.
- ^ The Sannai Maruyama Site-Food, Aomori Prefecture, Japan, p. 7.
- ^ (Japanese) (en abstract available) Michiko Niimi, Sea Mammal Hunting of the Jomon Culture in Hokkaido, Bulletin of the Department of Archaeology, 9 (19901228), 137-171, University of Tokyo ISSN 02873850
- ^ Terajima Ryōan, Wakan Sansai Zue (ca. 1712), vol. 38, Amimals, p. 72, sea lion and fur seal[1] "其肉亦不甘美 唯熬油為燈油 (the meat is not tasty and just used to render oil for oil lamps.)".
- ^ "Incorporation of Takeshima into Shimane Prefecture", Ministry of Foreign Affairs (Japan).
- ^ (Japanese) "李ライン翌年竹島にニホンアシカ多数生息", The San-in Chuo Shimpo, 2007/05/10. "研究の一環として聞き取り調査した杉原顧問は「戦前、隠岐の漁民は計画性を持ってニホンアシカを捕獲していた。韓国側は日本の乱獲が絶滅の原因というが、証言を聞く限り、乱獲したのはむしろ韓国の方だ」と韓国側の主張に反論した。"
- ^ (Korean)"일본어부에 의해 멸종당한 독도 강치", Dokdocenter.org, 2007-03-05. Retrieved on 2007-09-20.
- ^ a b c d (Korean) "독도에 바다사자 복원한다", The Kukmin Daily, 2006-02-02. Retrieved on 2007-09-21. a) "푸른울릉·독도가꾸기모임 이예균 회장은 "일본 자료를 살펴보면 독도는 단순히 바다사자가 살던 섬이 아니라 바다사자의 최대 번식지였다"며 "일본의 다케시마어렵회사가 1905년부터 8년 동안 독도에서 1만4천여마리나 집중 포획하면서 바다사자가 멸종의 길로 접어들었다"고 말했다.", b) "50년대 독도의용수비대가 활약할 당시만 해도 20∼30마리씩 떼를 지어 독도 연안에서 서식하는장면이 목격됐다. 독도의용수비대원이던 이규현씨(82·울릉군 울릉읍 도동리)는 "당시 독도에서 강치(바다사자) 무리를 간간이 볼 수 있었고, 울릉도 주민들은 이를 가재, 강치로 부르기도 했다"고 말했다." c) "환경부 관계자는 "독도 바다사자 복원사업을 시작하려면 반드시 독도만이 아니라 동해안 전역에 바다사자를 살게 하는 쪽으로 접근할 필요가 있다"고 말했다."
- ^ a b "Extinct Sea Lions to Bring Back to Korea", Korea Times, 2007-09-05. Retrieved on 2007-09-06.
- ^ (Korean) "독도 바다사자(강치) 복원에 대한 조사 및 타당성 검토요청 (Request for Research on Feasibility of Reintroducing Dokdo Sea Lions)", South Korean Ministry of Environment, 2006-01-09.
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