The Chinese paddlefish - one of the world's largest river fish - has gone extinct, according to a new paper published in the Science of the Total Environment.
The decline of the fish, which can grow up to seven meters in length, and which has a sword-like snout, has been put down to human activities.
According to the paper - titled Extinction of one of the world's largest freshwater fishes: Lessons for conserving the endangered Yangtze fauna - these include overfishing and habitat fragmentation.
'Efforts urgently needed'
The paper puts the timing of the extinction between 2005 and 201, saying the paddlefish became functionally extinct by 1993, prior to extinction.
Now the authors say 'efforts on endangered Yangtze [River] fishes are urgently needed'.
"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..." says the paper's abstract.
"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."