The mega river ecosystem of the Yangtze River was once home to diverse aquatic megafauna
but is increasingly affected by various anthropogenic stressors that have resulted
in continuous loss of biodiversity, such as the probable extinction of Yangtze River
Dolphin. The Chinese paddlefish, Psephurus gladius, was one of only two extant members
of a relict lineage that was most diverse and widespread 34-75 million years ago.
It is also one of the largest freshwater fish species, reaching up to 7 m in length.
The Chinese paddlefish was once common in the Yangtze River, with c.25 t being harvested
per annum during the 1970s. Populations have, however, declined drastically since
the late 1970s as a result of overfishing and habitat fragmentation. Here, a basin-wide
capture survey during 2017-2018 found 332 fish species, but did not find a single
specimen of Chinese paddlefish. Furthermore, 140 historically reported fish species
have not been found and most of them are considered highly endangered. Based on 210
sightings of Chinese paddlefish during the period 1981-2003, we estimated the timing
of extinction to be by 2005, and no later than by 2010. In addition, the paddlefish
probably became functionally extinct (i.e. it was unable to reproduce) by 1993, before
it went extinct. It is likely that the lack of reproduction was among the major causes
of extinction. As no individuals exist in captivity, and no living tissues are conserved
for potential resurrection, the fish should be considered extinct according to the
IUCN Red List criteria. The delayed extinction of Chinese paddlefish resulted from
multiple threats, suggesting that optimizing conservation efforts on endangered Yangtze
fauna is urgently needed.