“When yesterday’s poetry speaks today’s truth”, a study on the decline of Yangtze finless porpoises, a preview of “On the Trail” n°47, the defaunation bulletin, to be published in mid-November.
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“The Yangtze River, Yangzi River or Chang Jiang flows for 6,400 km from the plateaus of Tibet (5,300 km high) to the China Sea. It is the 3rd longest river in the world, a dragon with terrifying floods but fertile banks for the 350 million people who live along its spine. After rushing down the Himalayas and its foothills in its upper reaches, the Yangtze flows through the provinces of Sichuan and Hubei in its middle reaches. It then spreads out within the Three Gorges, a series of breathtakingly beautiful cliffs that have been celebrated and feared by sailors for thousands of years. The river rushes through, roaring, alternating between whirlpools (xuanwo), rapids (jiliu) and “water cannons” (shuipao)…” (La Flèche, Robin des Bois’ newspaper, n°27, May/June 1995, p.39, only in French)
It was here, at Sandouping, across these Three Gorges, that the largest hydroelectric dam (22,500 megawatts of installed capacity) was built between 1994 and 2012. The Yangtze basin is disrupted by 16 other hydroelectric dams of over 2,000 megawatts.
From 724 poems written during the Tang (618-907), Song (960-1279), Yuan (1271-1368), Ming (1368-1644) and Qing (1636-1912) dynasties that briefly mention Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis, Appendix I), Chinese lettered people and naturalists found that in 1,400 years the freshwater mammal’s range has shrunk by at least 65%. The range area decreased by 33% between the Tang dynasty and modern times on the main course of the Yangtze River. During the same period, it decreased by 91% in tributaries, sub-tributaries and lakes. The collapse occurred during the 20th century.
This poetic, topographical and cetological anthology reveals that the Yangtze finless porpoises have virtually disappeared from 300 km of the Yangtze River upstream of the Three Gorges Dam. They have also completely disappeared from the Yuan River (864 km), a tributary of the Yangtze, from the Xiao River (354 km), a tributary of the Xiang (856 km long) that flows into the Yangtze, downstream of the Three Gorges Dam, 900 km from the delta. They have disappeared from Dongting Lake (2,740 km²), fed by the Yangtze, Yuan, Xiang, Zi, Yang and Li rivers. They have disappeared from the Han River (1,532 km), a tributary of the Yangtze. They have disappeared into Lake Poyang (4,000 km²), 700 km from the delta. They have disappeared into Lake Chao (760 km²), 500 km from the delta, and Lake Shaobo (80 km²), 300 km from the delta. They have disappeared into the Huangpu River (110 km), a tributary of the Yangtze, 50 km from the delta. They have disappeared into Lake Tai (2,250 km²) near the delta and into the Yangtze Delta.
Estimated range of the Yangtze finless porpoise during the Tang Dynasty
Estimated range of the Yangtze finless porpoise at the end of the 20th century
The species’ habitat grid is superimposed on a map of China in the autonomous municipality of Chongqing and in the provinces of Guizhou, Hubei, Hunan, Jiangxi, Anhui and Jiangsu.
A major source of information for today’s scientists comes from the encyclopaedia Sancai Tuhui, literally “Compendium of the Three Powers”, dating from 1609, which in the Earth section briefly describes the morphological details, surface postures and maternal behaviours of Yangtze finless porpoises. The illustrations accompanying certain poems demonstrate that the authors had a precise knowledge of the species, as the backs are always devoid of fins. There can be no confusion with baijis (Lipotes vexillifer, CITES Appendix I) or Chinese river dolphins who are today regarded as extinct.
Excerpt from the Sancai Tuhui compiled by Wang Qi (1573–1620)
Excerpts from classical Chinese poems evoking Yangtze finless porpoises:
“The porpoises sometimes come out to play and the waves suddenly ripple.”
“The river is calm, the fishermen’s lights twinkle, the night is pitch black, and suddenly porpoises emerge from the waves, as if to greet the travellers.”
“Porpoises chased moonlight on silvered tides.”
The navigable range of Yangtze finless porpoises has therefore been considerably reduced, and the remaining population separated by dam walls numbers around a thousand in total. According to pessimists, the future of the species in the wild is doomed in the medium term by overpopulation and the cumulative discharge of sewage, industrial and agricultural effluents. Twenty years ago, an irreparable disaster occurred in Dongting Lake. Six Yangtze finless porpoises died within a week after violent exposure to hostathion, an organophosphate pesticide marketed by Bayer.
Yangtze finless porpoises and other critically endangered species such as the Yangtze sturgeon (Acipenser dabryanus, Appendix II) are also victims of electrofishing or accidental catches in fishing nets. Optimists say that the suspension of all fishing activities since 2021 should contribute to the resilience of the species. The Chinese Ministry of Agriculture and Rural Affairs is officially among them. In its 2022 census, it estimates the population at 1,249 specimens, up from 1,012 in 2017, an increase of 237.
China has a very long and respected tradition of written, illustrated and sung poetry dating back to the Western Zhou Dynasty (1045-771 BC). It is a rich source of information that could be used to conduct similar research on terrestrial megafauna and on avifauna.
This study is inspired by the article “Range contraction of the Yangtze finless porpoise inferred from classic Chinese poems” was written by Yaoyao Zhang, Kexiong Wang, Ding Wang and Zhigang Mei (Institute of Hydrobiology, Chinese Academy of Sciences), Jianghua Wang (College of Fisheries, Huazhong Agricultural University), Jiajia Liu and Shilu Zheng (National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Fudan University), with the assistance of Xiaoliang Zhang for the interpretation of classical Chinese.
Current Biology, Vol. 35, Issue 9, R329 – R330, May 5, 2025, doi: 10.1016/j.cub.2025.02.052.
Yangtze finless porpoises and baijis, see “On the Trail” n°16 p.13, n°30 p.198 (ref.7) and n°33 p.282-283 (ref.9).
On the Trail, the world as it is.
https://robindesbois.org/en/a-la-trace-bulletin-dinformation-et-danalyses-sur-le-braconnage-et-la-contrebande/
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