|Scientific Name:||Psephurus gladius|
|Species Authority:||(Martens, 1862)|
|Red List Category & Criteria:||Critically Endangered A2cd; C2a(i); D ver 3.1|
|Reviewer(s):||Pourkazemi, M., Zhang, H., Du, H. & Smith, K.|
The population of the Chinese Paddlefish decreased due to historical overfishing and habitat degradation. In 1981, the construction of the Gezhouba Dam in the middle reaches of the Yangtze River blocked the migration route of this species, preventing adult fish moving to the upper reaches of the river to spawn. Only two adult specimens (both females) have been recorded since 2002, despite recent surveys to re-discover the species. Juveniles were last recorded in the lower reaches of the river in 1995. It is expected that there are less than 50 mature individuals left in the wild and this species is assessed as Critically Endangered (Possibly Extinct), though more extensive surveys are needed in areas across the species range in order to confirm whether or not individuals of this species remain.
|Range Description:||The Chinese Paddlefish is endemic to the Yangtze River (including the brackish water of the mouth) in China.|
|Range Map:||Click here to open the map viewer and explore range.|
From the mid-20th century the population of the Chinese Paddlefish decreased significantly. Incidental capture data between 1982-2008 from the upper, mid and lower sections of the Yangtze River indicate the largest number of this species found during this period was in 1985, when 32 individuals were captured in the lower section (below the Gezhouba Dam) (Zhang et al. 2009). In 1995 juveniles of this species were recorded below the Gezhouba Dam of the Yangtze River (Chen 2008).
Two specimens (1.2 kg weight, 47 cm tail length; 1.3 kg weight, 50 cm tail length) were found in the Chongqing reach in 1992 (Chen 2007). In 2002, a female Chinese Paddlefish (body length 330 cm, weight 117 kg) was captured in the section of Jiangsu Nanjing, Yangtze River. Urgent attempts were made to save this individual, but it only survived in captivity for 30 days. On Jan 24th, 2003, a female (body length 352 cm) was accidentally caught in Yibin, Sichuan Province China (upper stream of Yangtze River). It was captured, tagged with an ultra-sonic tag and released by Dr. Wei’s team of the Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences. Unfortunately, after 12 hours of tracking, communication was disconnected. Between 2006 and 2008, Dr.Wei’s team used a number of boats to deploy 4,762 setlines, 111 anchored setlines and 950 drift nets covering a stretch of 412.5 km of the upper Yangtze River in a bid to catch the fish, but they failed to catch a single individual (Zhang et al. 2009). The team also used hydroacoustic equipment that beams sound through the water to create a picture of the river and anything in it. This identified nine possible targets, of which two could be paddlefish (Zhang et al. 2009). This species is considered to be the verge of extinction. Artificial reproduction has not been successful.
|Habitat and Ecology:||
This paddlefish is considered anadromous (spends at least part of its life in the sea and migrates upriver to reproduce). This species occurs in broad surfaced main streams of large rivers, staying usually in middle and lower layers of the water column, and occasionally swims into large lakes. Its spawning period is in March and April. Spawning sites are located in the upper reaches of the Changjiang River. Available information also indicates that spawning took place in the lower Jinsha River between Shuifu and Yibin (Liu and Zeng 1988, Li et al. 1997).
The largest specimen recorded was 7 m in length and weighed over several thousand pounds.
|Use and Trade:||This species has historically been overfished for human consumption.|
The Chinese Paddlefish has historically been overfished. The long-life history of this species (e.g. late sexual maturation and large size) means the population will take a longer time to recover from depletion.
In 1981 the Gezhouba Dam was built in the middle reaches of the Yangtze River, blocking the migration route of this species and preventing adult fish moving to the upper reaches of the river to spawn.
Fries of P. gladius form schools along the river, thus becoming easily captured in traditional Chinese fishing nets and set nets (Zhang et al. 2009).
P. gladius is listed as a first-class state protected animal in China. Due to its endemicity and rarity, this species possesses significant academic and economic importance. This species was listed on CITES Appendix II in 1998.
An integrated rescue programme was initiated in 2005. This extensive programme hopes to re-discover this species. It is also investigating habitat and plans to conduct studies on foraging behaviours and instigate captive breeding programmes, propagation for release, preservation of genetic resources, and even cloning (Zhang et al. 2009).
The “Protective Laws of Aquatic Products Resources” should be implemented and increased awareness of the significance of the protection of the species is needed (Wei Qiwei et al. 2003).
Current studies hope to investigate artificial breeding with the hope of releasing captive bred fries into rivers, ponds and reservoirs. The success of this work depends upon finding wild adult specimens.
Anonymous. 1988. The biology of sturgeons and paddlefish in the Yangtze and their artificial propagation [in Chinese]. Sichuan Scientific and Technical Publishing House, Chengdu, China.
Chen, X.H. 2007. Biology and resource situation of Acipenseriformes [in Chinese]. pp. 95-102. Ocean Press, Beijing.
Fan, X.G., Wei, Q.W., Chang, J., Rosenthal, H., He, J.X., Chen, D.Q., Shen, L., Du, H. and Yang, D.G. 2006. A review on conservation issues in the upper Yangtze River — a last chance for a big challenge: Can Chinese paddlefish (Psephurus gladius), Dabry´s sturgeon, (Acipenser dabryanus) and other fish species still be saved? Journal of Applied Ichthyology 22(suppl 1): 32–39.
Fu, C., Wu, J., Chen, J., Wu, Q. and Lei, G. 2003. Freshwater fish biodiversity in the Yangtze River basin of China: patterns, threats and conservation. Biodiversity and Conservation 12: 1649-1685.
IUCN. 2010. IUCN Red List of Threatened Species (ver. 2010.1). Available at: www.iucnredlist.org. (Accessed: 10 March 2010).
Mims, S.D. 2001. Aquaculture of paddlefish in the United States. Aquatic Living Resources 14: 391−398.
Yun, L., Xiaoming, D. and Jianhu, J. 1997. A preliminary study on the morphology, growth of juvenile Psephurus gladius on the upper reaches of the Changjiang River and a survey of its spawning grounds. Journal of Southwest Agriculture University 5: 448-450.
Zhang, H., Wei, Q., Du, H., Shen, L. Li, Y. 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(Suppl 2): 95-99.
Zhong, Y., Bin, Z. and Jianbo, C. 2008. DNA extraction formalin-fixed tissue of Psephurus gladius and the applicability of microsatellite primers developed from its related species. Journal of Lake Sciences 20(2): 242-250.
|Citation:||Qiwei, W. 2010. Psephurus gladius. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 01 October 2014.|
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