The Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) is currently limited to the middle and lower reaches of the Yangtze River from Yichang to Shanghai, China, and the adjoining Poyang and Dongting ...The Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) is currently limited to the middle and lower reaches of the Yangtze River from Yichang to Shanghai, China, and the adjoining Poyang and Dongting Lakes. Its population size has decreased remarkably during the last several decades due to the heavy impact of human activities, including overfishing of prey species, water development projects that cause attendant habitat loss and degradation, water pollution, and accidental deaths caused by harmful fishing gear and collisions with motorized vessels. It was estimated that the number of remaining individuals was down to approximately 1800 in 2006, a number that is decreasing at a rate as high as 5% per year. Three conservation measures-in situ and ex situ conservation and captive breeding have been applied to the protection of this unique porpoise since the early 1990s. Seven natural and two "semi-natural" reserves have so far been established. Since 1996, a small group of finless porpoises has been successfully reared in a facility at the Institute of Hydrobiology of the Chinese Academy of Sciences; three babies were born in captivity on July 5, 2005, June 2, 2007 and July 5, 2008. These are the first freshwater cetaceans ever born in captivity in the world. Several groups of these porpoises caught in the main stream of the Yangtze River, or rescued, have been introduced into the Tian'e-Zhou Semi-natural Reserve since 1990. These efforts have proven that, not only can these animals survive in the area, they are also to reproduce naturally and successfully. More than 30 calves had been born in the reserve since then, with one to three born each year. Taking deaths and transfers into account, there were approximately 30 individuals living in the reserve as of the end of 2007. Among eight mature females captured in April 2008, five were confirmed pregnant. This effort represents the first successful attempt at off-site protection of a cetacean species in the world, and establishes a solid base for con展开更多
This study presents the results of a demographic analysis of 20 years of birth and death records of red gorals kept at the Shanghai Zoo. The age of the first successful breeding, sex ratio at birth, seasonality of rep...This study presents the results of a demographic analysis of 20 years of birth and death records of red gorals kept at the Shanghai Zoo. The age of the first successful breeding, sex ratio at birth, seasonality of reproduction and mortality rate are presented. The females or males of red goral born in captivity can give their first birth at the age of 2 or 3 separately. The births mainly occurred from May to July and peaked in June. Ratio of females to males at birth was 2.36∶1. The mortality rate for infants and adults were 23.1% and 11.8%, respectively while there was no sub-adult death recorded during the 20 years period. There was a definite relation between mortality rate and seasons and mainly in July.展开更多
基金Supported by the National Key Basic Research and Development Program of China (Grant No. 2007CB411600)National Natural Science Foundation of China (Grant Nos. 30730018 and 30570252)Chinese Ministry of Science and Technology (2004DFB03000)
文摘The Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) is currently limited to the middle and lower reaches of the Yangtze River from Yichang to Shanghai, China, and the adjoining Poyang and Dongting Lakes. Its population size has decreased remarkably during the last several decades due to the heavy impact of human activities, including overfishing of prey species, water development projects that cause attendant habitat loss and degradation, water pollution, and accidental deaths caused by harmful fishing gear and collisions with motorized vessels. It was estimated that the number of remaining individuals was down to approximately 1800 in 2006, a number that is decreasing at a rate as high as 5% per year. Three conservation measures-in situ and ex situ conservation and captive breeding have been applied to the protection of this unique porpoise since the early 1990s. Seven natural and two "semi-natural" reserves have so far been established. Since 1996, a small group of finless porpoises has been successfully reared in a facility at the Institute of Hydrobiology of the Chinese Academy of Sciences; three babies were born in captivity on July 5, 2005, June 2, 2007 and July 5, 2008. These are the first freshwater cetaceans ever born in captivity in the world. Several groups of these porpoises caught in the main stream of the Yangtze River, or rescued, have been introduced into the Tian'e-Zhou Semi-natural Reserve since 1990. These efforts have proven that, not only can these animals survive in the area, they are also to reproduce naturally and successfully. More than 30 calves had been born in the reserve since then, with one to three born each year. Taking deaths and transfers into account, there were approximately 30 individuals living in the reserve as of the end of 2007. Among eight mature females captured in April 2008, five were confirmed pregnant. This effort represents the first successful attempt at off-site protection of a cetacean species in the world, and establishes a solid base for con
文摘This study presents the results of a demographic analysis of 20 years of birth and death records of red gorals kept at the Shanghai Zoo. The age of the first successful breeding, sex ratio at birth, seasonality of reproduction and mortality rate are presented. The females or males of red goral born in captivity can give their first birth at the age of 2 or 3 separately. The births mainly occurred from May to July and peaked in June. Ratio of females to males at birth was 2.36∶1. The mortality rate for infants and adults were 23.1% and 11.8%, respectively while there was no sub-adult death recorded during the 20 years period. There was a definite relation between mortality rate and seasons and mainly in July.
