A First Step for the Yangtze
As China has rapidly developed over the past 40 years, the Yangtze River has suffered a severe loss of biodiversity. The baiji (Yangtze river dolphin) is likely extinct (1), the Yangtze finless porpoise is critically endangered and declining (2), and more than 30% of Yangtze fish species are at the brink of extinction (3).
This year, a Chinese research team reported on the extinction of the Chinese paddlefish (4). The decline of vertebrate biodiversity in the Yangtze River is primarily attributable to illegal fisheries and excessive fishing (5). Chinese policy to discourage overfishing has improved, but more must be done to prevent the extinction of many of these species.
In 2002, China initiated an annual 3-month closure of all commercial fisheries on the Yangtze River. In 2016, the closure was increased to 4 months. Two years later, fisheries were banned in all of China’s aquatic biological reserves (2). Then, in January 2020, China instituted a 10-year ban on all commercial fishing in the Yangtze River and its tributaries, including the adjoining lakes (6).
The new regulations were enacted in an effort to save endangered Yangtze River aquatic life and prevent further extinctions. The initial 10-year period of the fishery ban was chosen because it will extend through two to three generations for most of the fish species in the Yangtze River(7).
Although implementation of the fishing ban will face many logistic difficulties, this is a momentous first step, which, together with a shift in public support for conservation (2), gives us great hope for the protection of aquatic life in the Yangtze River. Despite these positive steps, many species remain at risk of extinction.
It will be important to quantify the extinction risk for species in the Yangtze Basin in the coming years. We must also anticipate the disproportionate effects on biodiversity that could result from the loss of groups with a longer evolutionary history, fewer system branches, and fewer species (8, 9).
Because of its unique ancient evolutionary characteristics, the baiji was given conservation priority among the 4510 mammals in the world (9), and the Chinese paddlefish was the basal group in all ray-finned fish (10); now both are likely extinct.
To prevent further extinctions, in addition to adhering to the fishing ban, we must invest more in research to identify those (potentially less iconic) species that are at greatest risk of extinction and which would result in the greatest loss of global biodiversity. (Science)
REFERENCES AND NOTES
1. S. T. Turvey et al., Biol. Lett. 3, 537 (2007).
2. J. Huang et al., Biol. Cons. 241, 108315 (2019).
3. L. Cao et al., Biodivers. Sci. 24, 598 (2016).
4. H. Zhang et al., Sci. Total Environ. 710, 136242 (2019).
5. D. Dudgeon, in River Conservation: Challenges and Opportunities, S. Sabater, A. Elsosegi, Eds. (Fundación BBVA, Bilbao, Spain, 2013), pp. 129–167.
6. Notice of the Ministry of Agriculture and Rural Affairs on the scope and time of arrests in key waters of the Yangtze River Basin (www.cjyzbgs.moa.gov.cn/tzgg/201912/t20191227_6334009.htm) [in Chinese].
7. F. Liu et al., Acta Hydr. Sinica 43, 144 (2019).
8. D. P. Faith, Cladistics 8, 361 (1992).
9. N. J. Isaac et al., PLOS One 2, e296 (2007).
10. L. C. Hughes et al., Proc. Natl. Acad. Sci. U.S.A. 115, 6249 (2018).