Range-wide Yangtze freshwater dolphin expedition: The last chance to see Baiji?
- 448 Downloads
Background, Aim and Scope
There are two species of fresh water cetaceans surviving in the Yangtze River system in China: Baiji (Lipotes vexillifer) and Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis). As a result of the expansion of human activities on the river, their distribution ranges appear to be decreasing and in the case of the Baiji, are even being restricted to several sections. The Baiji is the world’s most critically endangered cetacean species with a population estimated at only a few tens of individuals. The Yangtze finless porpoise is the world’s only freshwater-adapted population of the species, and it has been estimated that only around 1,000 individuals remain in the river system. In order to prevent the extinction of Baiji and a sharp decline in the abundance of the porpoise, in situ conservation (i.e. in the river) and two ex situ conservation (i.e. in semi-natural reserves and in captivity) strategies were proposed and have been implemented since the early 1990s. In view of both the severely endangered status of the animals and the severely degraded conditions of their habitats, the feasibility and actual status of these two strategies are raised for discussion.
The threats faced by the cetaceans are mainly from the unfettered exploitation of the river’s resources. In the past 20 years, five nature reserves have been established along the river. Imposing maximum prohibition of harmful and illegal fishing methods in the reserves might prolong the process of extinction of these cetaceans in the wild, but so far, the administrative measures taken in the reserves have not yet kept the abundance from sharply declining. As human use of the river and its resources is expected to intensify for many decades into the future, the ability of the river to continue to support these species is certainly undecided. Therefore, rescuing animals from the river and establishing viable breeding populations in semi-natural reserves, in which the environment is similar to the main stream of the river, and in captivity, has to be considered urgently as the short-term goal of ex situ strategies. Since the abundance of porpoises is higher than that of the Baiji, we have first established breeding populations of them in the semi-natural reserves and in captivity. But, considering the extremely low density of Baiji in the river, an immediate range-wide Yangtze Baiji survey is an urgent need for locating and capturing sufficient Baiji for successfully establishing a breeding population of them in semi-natural reserves.
Two semi-natural reserves (in Shishou, Hubei Province, and Tongling, Anhui Province) have been set up along the river in order to establish breeding populations of the Baiji and the porpoises. So far, several small groups of porpoises that were caught in the main stream of the river have successively been introduced into the semi-natural reserves. Under careful management, these animals in both of the semi-natural reserves not only survive, but can also reproduce naturally and successfully. At least one or three calves were born in each reserve each year. Additionally, a breeding group of porpoises is being established at the Baiji Dolphinarium at the Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan. There are presently four adults and one calf living in the Dolphinarium. The calf, born in July, 2005, is the first captive bred Yangtze Finless Porpoise in the world. In preparation for the range-wide Yangtze cetacean survey, a 9-day pilot expedition on the river near Wuhan was conducted in March, 2006, in order to develop methods for locating the Baiji. No Baiji were expected to be seen in such a short period but about 40 porpoise sightings were observed. Results of the pilot survey indicated that traditional visual and acoustical survey methods for cetaceans should be adapted to find the elusive Baiji in the river. Currently, the range-wide Yangtze cetacean survey is in preparation. The survey will cover over 1,700 km of the Yangtze River from Yichang to Shanghai, and is expected to provide detailed information on Baiji and porpoise numbers and distribution patterns in the river.
Although the short-term goal of ex situ conservation is to rescue cetaceans from the river and to establish viable breeding populations in semi-natural reserves and in captivity, the long-term goal of releasing the animals back into the river when the threats have decreased and the natural environment has been improved, should not be neglected. Moreover, the in situ conservation efforts in the natural reserves, and even in the entire Yangtze River system, including the lakes, should not be ignored or abandoned at any time. The activities contributing to the conservation of the Baiji and the porpoise in the wild have the incidental effect of benefiting the entire Yangtze ecosystem and other rare threatened species. The dynamics of the groups of porpoises in semi-natural reserves should be monitored continually, in order to guide the establishment of breeding groups of Baiji in these semi-natural reserves in the near future.
Under the existing severely degraded conditions of the Yangtze system, the sharply fall populations of Baiji and porpoises will not be suspended in the foreseeable future. Therefore, ex situ conservation should be emphasized, and the severely threatened Baiji in the river should be removed and translocated to semi-natural reserves for establishing viable breeding populations. The successful program of capturing, translocating and maintaining finless porpoises in the Shishou semi-natural reserve has demonstrated its adequacy as an ex situ environment for cetaceans. Following the successful pilot survey in the river, the immediate range-wide Yangtze cetacean survey is proposed and is in preparation. The range-wide survey is expected to ensure that any remaining Baiji can be found reliably and captured successfully after the survey.
Recommendations and Perspectives
During the range-wide survey, not only the Baiji but also the porpoise as well as their habitats should be investigated based on visual and acoustical methods that adapted to the river and the animals. Meanwhile, the current risk levels to the Baiji and porpoises should be evaluated at each area where Baiji or porpoises can be reliably sighted. Any capture efforts should be targeted on the most threatened areas, or where there is maximum risk of injury or death. The immediate track of the Baiji should be carried out once a Baiji is sighted during the range-wide survey in order to obtain the movement route of the animals, which is crucial information for the successful capture operation. Additionally, the need to establish new semi-natural reserves for the porpoises should be placed on the agenda of local and central governments in the near future.
KeywordsBaiji (Lipotes vexillifer) breeding population conservation methods semi-natural reserve species protection range-wide cetacean survey Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis)
Unable to display preview. Download preview PDF.
- Barrett L, Pfluger A, Wang D (2006): Successful pilot Yangtze freshwater dolphin expedition. FFI Oryx 40(3) 257–258Google Scholar
- Barrett L, Wang D, Barlow J, Pitman B, Akamatsu T, Zhao X, Müller B, Pfluger A (2006): Pilot Expedition Report. San Diego, Wuhan, London, Zurich, 24th May 2006Google Scholar
- Braulik GT, Reeves RR, Wang D, Ellis S, Wells RS, Dudgeon D (2006): Report of the Workshop on Conservation of the Baiji and Yangtze Finless Porpoise. Baiji Foundation, ZurichGoogle Scholar
- Cetacean Specialist Group (1996): Neophocaena phocaenoides ssp. asiaeorientalis. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. 〈www.iucnredlist.org〉, downloaded on 21 September 2006
- Chen P (1989): Baiji Lipotes vexillifer (Miller, 1918). In: Ridgway SH, Harrison RJ (eds), Handbook of Marine Mammals. Volume 4: River Dolphins and the Larger Toothed Whales. Academic Press, London, pp 25–43Google Scholar
- Chen P, Hua Y (1989): Distribution, population size and protection of Lipotes vexillifer. In: Perrin WF, Brownell RL Jr, Zhou K, Liu J (eds), Biology and Conservation of the River Dolphins. IUCN SSC Occasional Paper No. 3, IUCN, Gland, Switzerland, pp 81–85Google Scholar
- Chen P, Liu P, Liu R, Lin K, Pilleri G (1980): The distribution, ecology, behaviour and protection of dolphins in the middle reach of Changjiang River (Wuhan — Yuayang). Invest Cetacea 10, 87–103Google Scholar
- Chen P, Liu R (1989): Captive husbandry of the Baiji, Lipotes vexillifer. In: Perrin WF, Brownell RL Jr, Zhou K, Liu J (eds), Biology and Conservation of the River Dolphins. IUCN Species Survival Commission Occasional Paper No. 3, IUCN, Gland, Switzerland, pp 146–149Google Scholar
- Chen P, Liu R, Wang D, Zhang X (1997): Biology, Rearing and Conservation of Baiji. Science Press, Beijing, 252 ppGoogle Scholar
- Dong W, Xu Y, Wang D, Hao Y (2006): Mercury concentrations in Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) from Eastern Dongtin Lake, China. Fresenius Environ Bull 15(5) 441–447Google Scholar
- IWC (International Whaling Commission) (2001): Annex K Report of the standing sub-committee on small cetaceans. J Cetacean Res Manage 3(Suppl) 263–291Google Scholar
- Kasuya T (2006): Japanese Whaling and Other Cetacean Fisheries. Environ Sci Pollut Res, OnlineFirst 〈DOI: http://dx.doi.org/10.1065/espr2006.09.346〉Google Scholar
- Lin K, Chen P, Hua Y (1985): Population size and conservation of Lipotes vexillifer. Acta Zool Sinica 5(1) 77–65Google Scholar
- Liu R, Wang D, Zhou K (2000): Effects of water development on river cetaceans in China. In: Reeves RR, Smith BD, Kasuya T (eds), Biology and Conservation of Freshwater Cetaceans in Asia. IUCN SSC Occasional Paper No. 23, IUCN, Gland, Switzerland and Cambridge, UK, pp 40–42Google Scholar
- Ministry of Agriculture (2001): Conservation action plan for cetaceans of the Yangtze River. Ministry of Agriculture, Beijing, ChinaGoogle Scholar
- Perrin WF, Brownell Jr RL (eds) (1989): Report of the Workshop on Biology and Conservation of the Platanistoid Dolphins. In: Perrin WF, Brownell RL Jr, Zhou K, Liu J (eds), Biology and Conservation of the River Dolphins. IUCN SSC Occasional Paper No. 3, IUCN, Gland, Switzerland, pp 1–22Google Scholar
- Perrin WF, Brownell RL, Zhou K, Liu J (eds) (1989): Biology and conservation of the river dolphins. World Conservation Union, Gland, SwitzerlandGoogle Scholar
- Reeves RR, Smith BD, Crespo EA, di Sciara GN (compilers) (2003): Dolphins, Whales and Porpoises: 2002–2010 Conservation Action Plan for the World’s Cetaceans. IUCN/SSC Cetacean Specialist Group, IUCN, Gland, Switzerland and Cambridge, UKGoogle Scholar
- Reeves RR, Smith BD, Kasuya T (eds) (2000): Biology and conservation of freshwater Cetaceans in Asia. World Conservation Union, Gland, SwitzerlandGoogle Scholar
- Reeves RR, Smith BD, Wang D, Zhou K (2005): Lipotes vexillifer. In: IUCN 2006. 2006 IUCN Red List of Threatened Species, 〈www.iucnredlist.org〉, downloaded on 21 September 2006
- Rice DW (1998): Marine Mammals of the World. Systematics and Distribution. Special Publication Number 4, The Society for Marine Mammalogy, Lawrence, KansasGoogle Scholar
- Samuel T, Barrett A, Braulik G, Wang D (2006): Implementing the recovery programme for the Yangtze River dolphin. FFI Oryx 40(3) 258–259Google Scholar
- Wang D (2000): Population status and conservation of Baiji and Yangtze finless porpoise. International Whaling Commission, Scientific Committee Document SC/52/SM17, Cambridge, UKGoogle Scholar
- Wang D, Liu R, Zhang X, Yang J, Wei Z, Zhao Q, Wang X (2000): Status and conservation of the Yangtze Finless Porpoise. In: Reeves RR, Smith BD, Kasuya T (eds), Biology and Conservation of Freshwater Cetaceans in Asia. IUCN SSC Occasional Paper No. 23, IUCN, Gland, Switzerland and Cambridge, UK, pp 81–85Google Scholar
- Wei Z, Wang D, Zhang X, Zhao Q, Wang K, Kuang X (2002): Population size, behavior, movement pattern and protection of Yangtze finless porpoise at Balijiang section of the Yangtze River. Resour Environ Yangtze Basin 11, 427–432Google Scholar
- Yang J, Xiao W, Kuang X, Wei Z, Liu R (2000): Studies on the distribution, population size and the activity of Lipotes vexillifer and Neophocaena phocaenoides in Dongting Lake and Boyang Lake. Resour Environ Yangtze Basin 9(4) 444–450Google Scholar
- Zhang X, Liu R, Zhao Q, Zhang G, Wei Z, Wang X, Yang J (1993): The population of Finless Porpoise in the middle and lower reaches of Yangtze River. Acta Theriol Sinica 13(4) 260–270Google Scholar
- Zhang X, Wang D, Liu R, Wei Z, Hua Y, Wang Y, Chen Z, Wang L (2003): The Yangtze River dolphin or Baiji (Lipotes vexillifer): population status and conservation issues in the Yangtze River, China. Aquat Conserv — Mar Freshwr Ecosyst 13, 51–64Google Scholar
- Zhang X, Wang K (1999): Population viability analysis for the Yangtze finless porpoise. Acta Ecol Sinica 19(4) 529–533Google Scholar
- Zhou K (2002): Baiji Lipotes vexillifer. In: Perrin W F, Würsig B, Thewissen J M G (eds) Encyclopedia of Marine Mammals. Academic Press, San Diego, CA, pp 59–61Google Scholar
- Zhou K, Ellis S, Leatherwood S, Bruford M, Seal U (1994): Baiji (Lipotes vexillifer) population and habitat viability assessment. Mammalogical Society of China, IUCN SSC Cetacean Specialist Group and IUCN SSC Captive Breeding Specialist GroupGoogle Scholar
- Zhou K, Li Y (1989): Status and aspects of the ecology and behaviour of the Baiji, Lipotes vexillifer in the lower Yangtze River. In: Perrin WF, Brownell RL Jr, Zhou K, Liu J (eds), Biology and Conservation of the River Dolphins. IUCN Species Survival Commission Occasional Paper No. 3, IUCN, Gland, Switzerland, pp 86–91Google Scholar
- Zhou K, Qian W, Li Y (1977): Studies on the distribution of Baiji, Lipotes vexillifer Miller. Acta Zool Sinica 23, 72–79Google Scholar
- Zhou K, Sun J, Gao A, Würsig B (1998): Baiji (Lipotes vexillifer) in the lower Yangtze River: movements, numbers, threats and conservation needs. Aquat Mammal 24, 123–132Google Scholar
- Zhou K, Yang G, Gao A, Sun J, Xu X (2000): Abundance and distribution of Finless Porpoises in the Nanjing-Hukou section of the lower Yangtze River. In: Reeves RR, Smith BD, Kasuya T (eds), Biology and Conservation of Freshwater Cetaceans in Asia. IUCN/SSC Occasional Paper No. 23, Gland, Switzerland and Cambridge, UK, pp 91–96Google Scholar
- Zhou K, Zhang X (1991): Baiji, the Yangtze River Dolphin and Other Endangered Animals of China. Yilin Press, Nanjing, China Received: October 4th, 2006Google Scholar