Solving the mystery of the disappearing Yangtze Finless porpoise

By | 2018-02-19T16:50:59+00:00 February 1st, 2017|Conservation, Extinction, Freshwater, Species|0 Comments

The Yangtze finless porpoise is a critically endangered subspecies of cetacean found only in the Yangtze river, China. Over the past two decades their population is believed to have dropped dramatically, but data are so sparse it is impossible to determine the extent or causes of this crash.

The Yangtze finless porpoise is now at extremely high risk of extinction, and urgent research is needed to understand the pressures on this freshwater cetacean. Synchronicity Earth is helping to support the Institute of Zoology/Zoological Society of London and University College London to carry out this research, in order to take effective action towards saving this species.

The Yangtze finless porpoise is a unique and charismatic freshwater porpoise endemic to the middle-lower reaches of the Yangtze river, China. Neophocaena asiaeorientalis ssp. asiaeorientalis is a subspecies of porpoise which, with a predicted population of just over 1,000 mature individuals, is classified as Critically Endangered on the IUCN Red List of Threatened Species and is listed under CITES Appendix I.

Only too recently, in 2006, the world saw the extinction of its first large vertebrate species for five decades – the Yangtze river dolphin or baiji. This species shared the same habitat as the porpoise and fears are that, if nothing is done, the porpoise may meet a similar fate. The finless porpoise reproduces slowly, meaning that as more and more are killed, the chances of the species recovering get lower. Recent estimates have predicted that if Yangtze finless porpoise populations continue to fall at current rates, it will be extinct in 25-33 years. On top of this, without clear knowledge of threats to the porpoise, there is no obvious path to its recovery.

Increases in human population and industrialisation of the porpoise’s home – the Yangtze – present a whole host of potential threats. High boat traffic makes collisions more likely, and increased sound pollution could affect communication and foraging. Entanglement in fishing gear and use of illegal and non-selective fishing methods (such as electro-fishing and gillnets) are thought to have been the main cause of extinction for the baiji, and could well be an issue for the porpoise. High levels of domestic, agricultural and industrial pollution could also be contributing to the declines, along with dams potentially impacting fish populations and altering hydrological conditions, sand dredging, and general habitat degradation.

Although all of these factors may well be contributing to the porpoise’s decline, so little is known about the ecology of this cetacean and how human activities affect its ecosystem that it is impossible to direct conservation action effectively towards the relevant threats. The ZSL/UCL team is carrying out research, including surveys of porpoise populations, interviews with local fishermen and other stakeholders about their fishing habits and other threats, and vital networking with NGOs in the area to develop a broad understanding of the porpoise’s situation and current management responses. This work is vital in identifying the steps that need to be taken before it is too late for another Yangtze vertebrate species.

In the video below, Sam Turvey, who is leading the research team, speaks about the demise of the Yangtze river dolphin (baiji). The aim of the current research is to help to ensure that the Yangtze Finless porpoise does not suffer the same fate.