Yangtze Finless Porpoise Born
Second Captive Birth Gives Hope as Wild Population Declines
The Yangtze River, once habitat for Baiji, is still home to the endangered finless porpoise. As numbers continue to decline, captive breeding offers chance for survival.
Fishing, boat traffic, bridge construction and dredging are having a major impact on the Yangtze River, its tributaries and Dongting and Poyang Lakes, where the Yangtze finless porpoise is found. Pollution from all this intensive activity only adds to the dangers the porpoise face. The Institute for Hydrobiology in Wuhan has developed a captive breeding program to help prevent the extinction of a second cetacean from this ecosystem.
Yangtze Finless Porpoise Status and Threats
The Yangtze finless porpoise (Neophocaena phocaenoides asiaorientalis) may number as few as 1000 animals. While finless porpoises are found in other parts of Asia, this subspecies is isolated from the rest. The Yangtze subspecies has been declared Endangered while the rest of the species remains Data Deficient. The Yangtze subspecies is now becoming separated into two subpopulations as bridge construction separates the porpoises found in the river from those inhabiting Poyang Lake. The bridge itself may present an audio barrier to ecolocation.
Dredging the lake for sand used in development in and around Shanghai is causing pollution, disturbance from noise and boat traffic and injury or death from propeller wounds. Fishing gear bycatch levels remain high as well. Construction of dams for hydroelectric power adds to the isolation of populations. Diversion of water for agriculture lowers river and lake levels reducing available habitat.
Captive Breeding Program
With numbers dropping rapidly, reversing the ecosystem damage may come too late for the Yangtze finless porpoise.So in order to ensure the species does not follow the Baiji into extinction, the Institute of Hydrobiology has begun a captive breeding program. Sadly, the program was actually begun to try to breed the Baiji in captivity. Only one male was ever successfully captured and kept alive so that project never really got off the ground.
Freshwater dolphins and porpoise are notoriously difficult to keep in captivity but the IHB has succeeded in maintaining 4 adult Yangtze finless porpoises, 2 males and 2 females. In 2005, the first captive bred male calf was born. In June of 2007, a second male calf followed. Two successful live births in two years is encouraging. But with only four adults as a gene pool, the dangers of inbreeding are high. With both calves being male and from the same female, there are further restrictions on how much interbreeding can safely occur.
Semi-Natural Reserve Population
Luckily, there is a second semi-captive population of Yangtze finless porpoise in the Tian’ezhou Semi-Natural Reserve, an oxbow that was once part of the Yangtze but is now isolated. A number of finless porpoise were relocated here a few years ago. This population is also small but 2 or 3 calves are born each year in an area protected from the dangers of the main river.
With luck these two isolated populations will continue to grow as the efforts to undo the damage to the Yangtze begin to return their natural habitat to a healthy state.
