Japanese sea lion

Japanese sea lion
Taxidermied specimen, TennŨji Zoo, Osaka, Japan

Extinct  (1970s)  (IUCN 3.1)[1]
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Otariidae
Subfamily: Otariinae
Genus: Zalophus
Species: Z. japonicus
Binomial name
Zalophus japonicus
(Peters, 1866)

The Japanese sea lion (Japanese: ćƒ‹ćƒ›ćƒ³ć‚¢ć‚·ć‚« Hepburn: Nihon ashika, Zalophus japonicus) is an aquatic mammal thought to have become extinct in the 1970s.[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 Z. japonicus, Z. californianus, and Z. 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 in the National Museum of Natural History, Leiden, the Netherlands, bought by Philipp Franz von Siebold.[3] The British Museum possesses a pelt and four skull specimens.[3]

Physical description

Taxidermied specimen at AQUAS

Male Japanese sea lions were dark grey and weighed about 450 to 560 kg, reaching lengths of 2.3 to 2.5 m; these were larger than male California sea lions. Females were significantly smaller at 1.64 m long with a lighter colour than the males.[2]

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 (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 BoHai Sea, the Yellow Sea, and Sea of Japan.[4] The sea lions and seals left relevant place names all over the coast line of Japan, such as Ashika-iwa (ć‚¢ć‚·ć‚«å²©, sea lion rock) and Inubosaki (ēŠ¬å å´ˇ, dog-barking point) because of the similarity of their howls.

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]

Human uses

Sea lion (right) and fur seal, Wakan Sansai Zue (around 1712)

Many bones of the Japanese sea lion have been excavated from shell middens from the JŨmon period in Japan[8][9][10] 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.[11] Valuable oil was extracted from the skin, its internal organs were used to make expensive oriental medicine, and its whiskers and leather were used as pipe cleaners and leather goods, respectively. At the turn of the 20th century, they were captured for use in circuses.[1]

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 overhunting caused harvest numbers to fall drastically to 300 sea lions by 1915 and to few dozen sea lions by the 1930s. Japanese commercial harvest of Japanese sea lions ended in the 1940s when the species became virtually extinct.[12] 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.[13][14] 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.[2][13][15]

Population revival efforts

In 2007, the South Korean Ministry of Environment has announced that South and North Korea, Russia, and China will collaborate on bringing back the Japanese sea lion in the Sea of Japan.[16] The National Institute of Environmental Research of Korea was commissioned to conduct feasibility research for this project.[17] If the animal cannot be found, the South Korean government plans to relocate California sea lions from the United States.[14] The South Korean Ministry of Environment supports the effort because of the symbolism, national concern, the restoration of the ecological system, and possible ecotourism.[13]

References

  1. 1 2 3 4 Aurioles, D. & Trillmich, F. (IUCN SSC Pinniped Specialist Group) (2008). Zalophus japonicus. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 7 January 2009.
  2. 1 2 3 4 (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 the 1930s from overhunting and increased competition with commercial fisheries. The last record in Japan was a juvenile, captured in 1974 off the coast of Rebun Island, northern Hokkaido."
  3. 1 2 3 (Japanese) "ćƒ‹ćƒ›ćƒ³ć‚¢ć‚·ć‚«å‰�č£½ęØ™ęœ¬", Shimane University Museum, Shimane University, Japan.
  4. 1 2 (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", 釡ē”Ÿē”Ÿē‰©äæ¯č­· (Wildlife conservation Japan),Vol.6, No.2 (20010731), 51-66, Wildlife Conservation Society ISSN 1341-8777.
  5. ā†‘ (Japanese) "天ēˇ‹åÆŗå‹•ē‰©åœ’ć§ć€Œēµ¶ę»…ć®å¨±ę©Ÿć«ć‚ć‚‹å‹•ē‰©å±•ć€¨ć‚’é–‹å‚¬ć—ć¾ć™" Tennoji Zoo, Osaka, Japan.
  6. ā†‘ Zalophus californianus japonicus (EX), Red Data Book Tottori (mammals), Tottori Prefecture, Japan, p. 34.
  7. ā†‘ (Japanese) Zalophus californianus japonicus (EX), Shimane Red Data Book 2004, Shimane Prefecture, Japan.
  8. ā†‘ The Jomon people in the northern Island, National Museum of Japanese History.
  9. ā†‘ The Sannai Maruyama Site-Food, Aomori Prefecture, Japan, p. 7.
  10. ā†‘ (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 0287-3850
  11. ā†‘ Terajima RyŨan, Wakan Sansai Zue (ca. 1712), vol. 38, Amimals, p. 72, sea lion and fur seal "å…¶č‚‰äŗ¦äø¨ē”˜ē¾ˇ å”Æē†¬ę²¹ē‚ŗē‡ˆę²¹ (the meat is not tasty and just used to render oil for oil lamps.)".
  12. ā†‘ ģ¯¼ė³øģ–´ė¶€ģ— ģ¯˜ķ•´ ė©øģ¢…ė‹¹ķ•œ ė¸…ė¸„ ź°•ģ¹˜ (in Korean). Dokdocenter.org. 2007-03-05. Retrieved 2007-09-20.
  13. 1 2 3 ė¸…ė¸„ģ— ė°”ė‹¤ģ‚¬ģ˛ ė³µģ›ķ•œė‹¤ (in Korean). The Kukmin Daily archived by Korea Coast Guard. 2006-02-02. Retrieved 2008-07-18.a) "ķ‘øė�øģšøė¦‰Ā·ė¸…ė¸„ź°€ź¾øźø°ėŖØģ˛„ ģ¯´ģ˜ˆź·  ķšŒģ˛�ģ¯€ "ģ¯¼ė³ø ģ˛ė£Œė�¼ ģ‚´ķˇ´ė³´ė©´ ė¸…ė¸„ėŠ” ė‹Øģˆœķ˛ˆ ė°”ė‹¤ģ‚¬ģ˛ź°€ ģ‚´ė¨˜ ģ„¬ģ¯´ ģ•„ė‹ˆė¯¼ ė°”ė‹¤ģ‚¬ģ˛ģ¯˜ ģµœėŒ€ ė²ˆģ‹¯ģ§€ģ˜€ė‹¤"ė©° "ģ¯¼ė³øģ¯˜ ė‹¤ģ¼€ģ‹œė§ˆģ–´ė µķšŒģ‚¬ź°€ 1905ė…„ė¶€ķ„° 8ė…„ ė¸™ģ•ˆ ė¸…ė¸„ģ—ģ„œ 1ė§Œ4ģ²œģ—¬ė§ˆė¦¬ė‚˜ ģ§‘ģ¤‘ ķ¸¬ķš¨ķ•˜ė©´ģ„œ ė°”ė‹¤ģ‚¬ģ˛ź°€ ė©øģ¢…ģ¯˜ źøøė�œ ģ ‘ģ–´ė“¤ģ—ˆė‹¤"ź³  ė§ķ–ˆė‹¤.", b) "50ė…„ėŒ€ ė¸…ė¸„ģ¯˜ģš©ģˆ˜ė¹„ėŒ€ź°€ ķ™œģ•½ķ•  ė‹¹ģ‹œė§Œ ķ•´ė¸„ 20āˆ¼30ė§ˆė¦¬ģ”© ė–¼ė�¼ ģ§€ģ–´ ė¸…ė¸„ ģ—°ģ•ˆģ—ģ„œ ģ„œģ‹¯ķ•˜ėŠ”ģ˛�ė©´ģ¯´ ėŖ©ź²©ėė‹¤. ė¸…ė¸„ģ¯˜ģš©ģˆ˜ė¹„ėŒ€ģ›ģ¯´ė¨˜ ģ¯´ź·œķ˜„ģ”Ø(82Ā·ģšøė¦‰źµ° ģšøė¦‰ģ¯¨ ė¸„ė¸™ė¦¬)ėŠ” "ė‹¹ģ‹œ ė¸…ė¸„ģ—ģ„œ ź°•ģ¹˜(ė°”ė‹¤ģ‚¬ģ˛) ė¬´ė¦¬ė�¼ ź°„ź°„ģ¯´ ė³¼ ģˆ˜ ģ˛ˆģ—ˆź³ , ģšøė¦‰ė¸„ ģ£¼ėƼė“¤ģ¯€ ģ¯´ė�¼ ź°€ģ˛¬, ź°•ģ¹˜ė�œ ė¶€ė�´źø°ė¸„ ķ–ˆė‹¤"ź³  ė§ķ–ˆė‹¤." c) "ķ™˜ź²½ė¶€ ź´€ź³„ģ˛ėŠ” "ė¸…ė¸„ ė°”ė‹¤ģ‚¬ģ˛ ė³µģ›ģ‚¬ģ—…ģ¯„ ģ‹œģ˛‘ķ•˜ė ¤ė©´ ė°˜ė“œģ‹œ ė¸…ė¸„ė§Œģ¯´ ģ•„ė‹ˆė¯¼ ė¸™ķ•´ģ•ˆ ģ „ģ—­ģ— ė°”ė‹¤ģ‚¬ģ˛ė�¼ ģ‚´ź²Œ ķ•˜ėŠ” ģŖ½ģœ¼ė�œ ģ ‘ź·¼ķ•  ķ•„ģš”ź°€ ģ˛ˆė‹¤"ź³  ė§ķ–ˆė‹¤."
  14. 1 2 "Extinct Sea Lions to Bring Back to Korea". Korea Times. 2007-09-05. Retrieved 2015-08-12.
  15. ā†‘ "Encyclopedia of Marine Mammals second edition". Academic Press 2008. 2008. Retrieved 2011-05-23.
  16. ā†‘ The Extinction Website: Zalophus japonicus
  17. ā†‘ (Korean) "ė¸…ė¸„ ė°”ė‹¤ģ‚¬ģ˛(ź°•ģ¹˜) ė³µģ›ģ— ėŒ€ķ•œ ģ�°ģ‚¬ ė°¸ ķƒ€ė‹¹ģ„± ź²€ķ† ģš”ģ²­ (Request for Research on Feasibility of Reintroducing Dokdo Sea Lions)", South Korean Ministry of Environment, 2006-01-09.
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