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Chinese paddlefish

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Chinese paddlefish
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Acipenseriformes
Family: Polyodontidae
Genus: †Psephurus
Günther, 1873
Species:
†P. gladius
Binomial name
†Psephurus gladius
(von Martens, 1862)
Synonyms[2][3]
  • Polyodon gladius von Martens 1862
  • Spatularia (Polyodon) angustifolium Kaup 1862
  • Polyodon angustifolium (Kaup 1862)

The Chinese paddlefish (Psephurus gladius) (simplified Chinese: 白鲟; traditional Chinese: 白鱘; pinyin: báixún), also known as Chinese swordfish, was among the largest freshwater fish, although the species was anadromous.[1] It was the only species in the genus Psephurus and one of two extant species in the paddlefish family (Polyodontidae), the other being the American paddlefish (Polyodon spathula). The Chinese paddlefish is at least critically endangered and has not been seen in more than a decade, and following the lack of specimens in capture surveys, it is now likely extinct.[1][4] However, this not currently official according to the IUCN, and will likely be updated in June 2020.[5]

Name

In Chinese this paddlefish is also called "elephant fish" (象魚; xiàngyú) because its snout vaguely resembles an elephant trunk. It is recorded sometimes in Classical Chinese as wěi-fish (鮪). More poetically, it is sometimes referred to as the "Giant Panda of the Rivers", not because of any physical resemblance to a giant panda, but because of its rarity and protected status. The origin of its binomial name comes from the Greek words pseph (pebble) and phoreus (bearer of), which when combined, also shares the meaning of the Greek word psepharos (gloomy/cloudy one).[citation needed]

Range and habitat

A specimen of Psephurus gladius exhibited in the Museum of Hydrobiological Sciences of Wuhan Institute of Hydrobiology

The Chinese paddlefish is restricted to China, where found in the Yangtze River basin (Chang Jiang) and its estuary at the East China Sea. Historically it was also recorded in Yellow River basin (which is connected to the Yangtze by the Grand Canal) and its estuary at the Yellow Sea.[6][7][8]

Chinese paddlefish spend part of their life in the lower section of the Yangtze, including the brackish water of its estuary, but migrate up the river and its major tributaries to spawn, which occur from March and April.[1] It generally stays in large rivers, but sometimes occur in large lakes.[1]

Appearance

The underbelly of the Chinese paddlefish is white, and its back and head are grey. They reach sexual maturity at a weight of around 25 kg (55 lb),[6] usually by the time they are age seven or eight, with a typical body length of 2 m (6 ft 7 in).[citation needed] Anecdotal reports indicate the Chinese paddlefish can reach 7 m (23 ft) in length and weigh up to 500 kg (1,100 lb),[9] or even several thousand pounds.[10] Limited research has been conducted on the species maximum size and weight as a result of its endangered status and lack of sightings over the years. A more generally accepted maximum size is 300 kg (660 lb) in weight and 3 m (10 ft) in length,[9] although the specimen caught in 2007 was 3.6 m (12 ft) long.[11]

Conservation status

The Chinese paddlefish has been listed as a first-level protected animal of the People's Republic of China since 1983 and on CITES Appendix II since 1998. Due to overfishing and habitat loss, the Chinese paddlefish is considered critically endangered by the IUCN.[1] The schooling young were easily caught by traditional fishing methods. Dams, notably the Gezhouba Dam and Three Gorges Dam, divided the populations and prevented their up- and downstream breeding migration.[1]

17th-century depiction.

The last records of Chinese paddlefish in the Yellow River basin and its estuary are from the 1960s, although the decline itself lasted between the 13th and 19th centuries.[7][4][8] In its main range, the Yangtze basin, the species has also strongly declined, but 25 tonnes were still annually captured in the 1970s. It was still found in some numbers in the 1980s (for example, 32 ere caught in 1985) and young were allegedly seen as recently as 1995.[1] Since 2000, there have only been three confirmed sightings of the fish alive, all from the Yangtze basin: The first was a 3.3-metre (11 ft), 117-kilogram (258 lb) female caught at Nanjing in 2002 and the second a 3.52-metre (11.5 ft) female caught at Yibin on January 24, 2003; the former died despite attempts to save it and the latter was radio-tagged and released, but the tag stopped working after only 12 hours.[1][12] The third and most recent was a 3.6-metre (12 ft), 250-kilogram (550 lb) specimen captured by illegal fishing on January 8, 2007, in Jiayu County. Local villagers contacted officials who rushed to the site. Zeb Hogan of the TV-series Monster Fish on National Geographic Channel and other conservationists transferred the fish to a holding pen in hope that it would survive, but it died shortly afterwards due to unrecoverable injuries sustained while thrashing in the net.[11] During a search conducted in the Yangtze basin from 2006–2008, a research team from the Chinese Academy of Fisheries Science in Jingzhou failed to catch any paddlefish,[12] but two probable specimens were recorded with hydroacoustic signals.[13] Although very small numbers might survive,[1] many scientists now consider the Chinese paddlefish to be extinct.[14]

A 2019 study reaffirmed the species as likely extinct following extensive capture surveys of the Yangtze between 2017 and 2018 that did not report any live specimens of the paddlefish. The paper estimated that the species went extinct between 2005 and 2010, and became functionally extinct by 1993. The study found the species' extinction to have been primarily caused by overfishing and habitat fragmentation, with one of the main contributors being the construction of the Gezhouba Dam in 1981. The paper thus recommended the reclassification of the species as Extinct by the IUCN.[4]

See also

References

  1. ^ a b c d e f g h i j Qiwei, W. "Psephurus gladius". IUCN Red List of Threatened Species. 2010. {{cite iucn}}: error: unknown url (help)
  2. ^ Froese, R.; Pauly, D. (2017). "Polydontidae". FishBase version (02/2017). Archived from the original on 24 August 2017. Retrieved 18 May 2017.
  3. ^ "Polydontidae" (PDF). Deeplyfish- fishes of the world. Archived (PDF) from the original on 24 August 2017. Retrieved 18 May 2017.
  4. ^ a b c Zhang, Hui; Jarić, Ivan; Roberts, David L.; He, Yongfeng; Du, Hao; Wu, Jinming; Wang, Chengyou; Wei, Qiwei (2019-12-23). "Extinction of one of the world's largest freshwater fishes: Lessons for conserving the endangered Yangtze fauna". Science of the Total Environment. 710: 136242. doi:10.1016/j.scitotenv.2019.136242. ISSN 0048-9697.
  5. ^ "IUCN". Weibo (in Chinese).{{cite web}}: CS1 maint: url-status (link)
  6. ^ a b "Species Fact Sheets: Psephurus gladius (Martens, 1862)". Food and Agricultural Organization of the United Nations. Archived from the original on 19 April 2012. Retrieved 1 February 2019.
  7. ^ a b Xie, J.Y.; W.J. Tang; Y.H. Yang (2018). "Fish assemblage changes over half a century in the Yellow River, China". Ecology and Evolution. 8 (8): 4173–4182. doi:10.1002/ece3.3890. PMC 5916296. PMID 29721289.
  8. ^ a b Li, S.Z. (2015). Fishes of the Yellow River and Beyond. The Sueichan Press. pp. 61–63. ISBN 9789578596771.
  9. ^ a b Froese, Rainer; Pauly, Daniel (eds.). "Psephurus gladius". FishBase. July 2010 version.
  10. ^ "Psephurus gladius". IUCN Red List of Threatened Species. 2010. 2010. Retrieved June 3, 2017.
  11. ^ a b "Chinese Paddlefish Dies in Illegal Fishing". CRIENGLISH.com. China Radio International. 2007-01-12. Archived from the original on 2016-03-04. Retrieved 2009-09-29.
  12. ^ a b Bourton, Jody (2009-09-29). "Giant fish 'verges on extinction'". BBC News. London: BBC. Archived from the original on 2012-04-19. Retrieved 2009-09-29.
  13. ^ Zhang; Wei1, Q.W.; Du, H.; Shen, L.; Li, Y.H.; and Zhao, Y. (2009). Is there evidence that the Chinese paddlefish (Psephurus gladius) still survives in the upper Yangtze River? Concerns inferred from hydroacoustic and capture surveys, 2006–2008. Journal of Applied Ichthyology 25(s2): 95-99. DOI: 10.1111/j.1439-0426.2009.01268.x.
  14. ^ "14 Animals Declared Extinct - Chinese Paddlefish". Christian Science Monitor. Archived from the original on 20 November 2016. Retrieved 20 January 2017.

Media related to Psephurus gladius at Wikimedia Commons

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