痛心疾首啊，长江白鳍豚从地球上消失了!！我真不愿意相信这是真的!!我们只能从历史文献中寻找她的踪迹了——
两千多年前，《尔雅》便有记载：“鱀，体似鲟，尾如鱼。喙小，锐而长，齿罗生，上下相衔，鼻在额上，能作声，少肉多膏，胎生，健啖细鱼，大者长丈余。江中多有之。”
蒲松龄《聊斋志异•白秋练》原文被收录在新版高中语文书中，作为阅读材料[另：现代白话文介绍]。不知大家读过没有？别只当爱情故事读，人与白鳍豚确是处在共同生存的生物链上啊！白鳍豚的绝灭，将是人类绝灭之始[观点来自一个钟爱白鳍豚的人]！
白鳍豚
Lipotes vexillifer Miller白鳍豚又名白鱀豚，俗称白鳍、白夹、江马，英文名：Yangtze river dolphin，属于鲸目(Cetacea)，喙豚科。
识别特点为：吻突狭长，长约300毫米。额部圆而隆起。背鳍三角形，位于身体的3/5处，有低皮肤脊与尾鳍相连。头顶的偏左侧有一个能启闭自如的呼吸孔。尾鳍水平向，向缘凹入呈新月形。白暨豚种群数量很小，为我国特有的珍稀水生兽类，亟待加强保护。白鳍豚属的哺乳动物，是中国特有的淡水豚类，也是世界上淡水豚类中数量最少的一种，由于数量稀少且为中国特有，被人们称为“水中大熊猫”。它是国家一级保护动物，目前仅分布在长江中、下游干流的湖北枝城至长江口约1600余公里的江段内。以鱼为食，结群活动，小群2～3头，大群10～16头。近年来种群数量下降极快。据报道，80年代初有400多头，80年代中期减至300来头，1990年调查时有200来头，至1993年为130余头，而到1995年已不足100头，被列为世界级的濒危动物。 三峡工程建在长江上游的出口处，不在白鳍豚的栖息范围内，不会直接危及它们的生存。但是三峡工程对长江水文情势的调节，则有可能对其栖息地产生影响。白鳍豚主要栖息在弯曲河段和弯曲分汉河段的大回水区中，当河势改变，大回水区发生移动时，白鳍豚也相应迁移，迁移距离的长短，与大回水区移动距离长短有关。三峡水库下泄清水对河床的冲刷，有可能使大回水区变动，使白鳍豚的栖息地迁移，按最严重的估计，白鳍豚的栖息地有可能下移150余公里，不到现在分布范围的1／10。另外，航运条件改善后，航行船舶增多，有可能使白鳍豚发生意外死亡的几率增加。为保护这一濒临绝灭的珍贵水生动物，国家已在长江中游的螺山至新滩口江段和石首天鹅洲长江故道以及长江下游的铜陵江段分别建立了白鳍豚自然保护区。
分类地位：哺乳纲、鲸目、淡水豚科，白鳍豚属。
外部形态：体长2米，体重100～200千克。吻部狭长，约有30厘米，上下颔两边密排着130多棵圆锥形的牙齿，前额呈园形隆起。皮肤细腻光滑，背面是浅灰蓝色，腹面是洁白色，体表呈流线形，前肢为鳍肢，背鳍呈三角形。后肢退化，尾部未端左右平展，分成两叶，呈新月形。有一个长园形凹穴状的鼻子或呼吸孔长在头顶的左上方。眼睛只有绿豆粒一般大小，已经退化，位于嘴角的后上方。耳朵只有一个针眼大小的洞，位于眼的后方，外耳道已经消失。
分布地点：分布于我国长江自三峡的黄陵庙以下，一直到长江口，以及沿江的大型湖泊和较大的支流中。生活习性：视觉、听觉、嗅觉均己退化。在水中联系同类，趋避敌害，识别物体和探测食物等，完全依靠发出的声纳信号。性情温顺。以鲤鱼、鲢鱼、草鱼、青鱼、三角鲂、赤眼鳟、鲶鱼等淡水鱼类为食。每年有两次发情期，分别在3～5月和8～10月。怀孕期10～ll个月。每胎仅产1仔。生存状况：50年代时长江中尚可见到较大群体，但此后白鳍豚的数量却急剧下降，在沿江湖泊和支流中消失，长江中的个体己不足100只，仅残存在长江中游的枝城到南京一段。在我国《国家重点保护野生动物名录》中被列为1级保护动物；在《中国濒危动物红皮书·兽类》中被列为濒危种，列《华盛顿公约》附录：一类保护动物。 以上转自百度百科
白鳍豚似鱼非鱼，胎生、哺乳。为适应水中的生活环境，它逐渐变化成像鱼的样子，但却没有腮，而用肺呼吸。长有130颗牙齿，却不用它咀嚼，而是咬住食物以后，囫囵吞下。白鳍豚两个后肢蜕化消失，前肢演化为鳍，但内部结构却有和人手相似的桡骨、尺骨、腕骨、指骨。白鳍豚心脏分四腔，体温恒定。所有这一切都说明它是哺乳动物而并非鱼类。
背呈浅灰色或蓝色，腹面为纯白色，背鳍形如一个小三角，胸鳍宛如两只手掌，尾鳍扁平，中间分叉，善于游水，时速可达80千米左右。尾鳍不像鱼一样上下垂直，而是从水平方向分成两叶，可以上下摆动，从而推动躯体前进。加之它是标准的流线体型，皮肤构造特殊，所以游动速度特别快。它还能发出叫声，不同的声音反映其不同的感情。它可长到2～3米长，200～300公斤重，可额头上的一对眼睛却小如绿豆。它对气候变化特别敏感，风雨之前常频频露出水面，所以被鱼民看作可以呼风唤雨的“神鱼” 。
由于长期生活在浑浊的江水中，白鳍豚的视听器官已经退化。它眼小如瞎子，耳孔似针眼，位于双眼后下方。但大脑特别发达，声纳系统极为灵敏，头部还有一种超声波功能，能将江面上几万米范围内的声响迅速传入脑中。一旦遇上紧急情况，便立刻潜水躲避。白鳍豚耐寒，体温通常在36℃左右，喜欢生活在江河的深水区，很少靠近岸边和船只，但它时常游弋至浅水区，追逐鱼虾充饥。它的吻宽细长，上下颌长有130多枚圆锥形的同型齿，可它却懒得咀嚼,只管张口吞下鱼食，消化能力很强。白鳍豚往往成对或三五成群一起活动，但人们很少有机会看到它，只有在它露出水面呼吸时才能瞥见一眼。
今年曾进行过初测，当时就认为是最后的希望，现在大规模的探测之后，一头也没发现！难道我们连最后的希望也没了么？我们是历史的罪人……
News
Last hope for river dolphins [Nature 440, 1096-1097 (27 April 2006) doi:10.1038/4401096b]
Rex Dalton
Abstract
But preliminary survey fails to find any surviving 'baiji'.
The world's most critically endangered cetacean, the Chinese 'baiji' river dolphin, may finally have a chance of being saved from extinction. But it could be too late; researchers who carried out a nine-day pilot search for the dolphins last month didn't find a single one.
The freshwater baiji (Lipotes vexillifer) once thrived in their only habitat, the Yangtze River, which runs though central China. But fewer than 100 dolphins are thought to be left in the river, which has become a busy, polluted highway. "If the giant panda is China's symbol of the destruction of forests, the baiji stands for polluted waters," says Wang Ding, from the Wuhan Institute of Hydrobiology.
An international team of scientists, led by Ding, is hoping to catch the animals and release them in a safer place, possibly the Shishou reserve, which is a 20-kilometre arm off the Yangtze.
But first the researchers —from China, the United States, Britain and Switzerland — need to find out exactly how many of the dolphins remain and where they are. They are preparing to conduct a search of 1,700 kilometres of the river in November, but carried out a pilot survey in March to refine their techniques.
The baiji are so few and far between that the best way to spot them is with acoustic devices. But that's a challenge. "The river is so noisy you can't use traditional acoustic equipment," explains Jay Barlow, a marine mammalogist from the US National Marine Fisheries Service in La Jolla, California, who was on last month's cruise. He and his colleagues are working on a method to clean up recordings from hydrophones, to isolate the baiji's distinctive whistles.
The researchers were disappointed not to see a single baiji on their recent search, but their hopes are now focused on the full-scale survey in November. "If none are found then, the burden of proof will change," says Barlow. "The species will be considered extinct unless proven otherwise."
两千多年前，《尔雅》便有记载：“鱀，体似鲟，尾如鱼。喙小，锐而长，齿罗生，上下相衔，鼻在额上，能作声，少肉多膏，胎生，健啖细鱼，大者长丈余。江中多有之。”
蒲松龄《聊斋志异•白秋练》原文被收录在新版高中语文书中，作为阅读材料[另：现代白话文介绍]。不知大家读过没有？别只当爱情故事读，人与白鳍豚确是处在共同生存的生物链上啊！白鳍豚的绝灭，将是人类绝灭之始[观点来自一个钟爱白鳍豚的人]！
白鳍豚
Lipotes vexillifer Miller白鳍豚又名白鱀豚，俗称白鳍、白夹、江马，英文名：Yangtze river dolphin，属于鲸目(Cetacea)，喙豚科。
识别特点为：吻突狭长，长约300毫米。额部圆而隆起。背鳍三角形，位于身体的3/5处，有低皮肤脊与尾鳍相连。头顶的偏左侧有一个能启闭自如的呼吸孔。尾鳍水平向，向缘凹入呈新月形。白暨豚种群数量很小，为我国特有的珍稀水生兽类，亟待加强保护。白鳍豚属的哺乳动物，是中国特有的淡水豚类，也是世界上淡水豚类中数量最少的一种，由于数量稀少且为中国特有，被人们称为“水中大熊猫”。它是国家一级保护动物，目前仅分布在长江中、下游干流的湖北枝城至长江口约1600余公里的江段内。以鱼为食，结群活动，小群2～3头，大群10～16头。近年来种群数量下降极快。据报道，80年代初有400多头，80年代中期减至300来头，1990年调查时有200来头，至1993年为130余头，而到1995年已不足100头，被列为世界级的濒危动物。 三峡工程建在长江上游的出口处，不在白鳍豚的栖息范围内，不会直接危及它们的生存。但是三峡工程对长江水文情势的调节，则有可能对其栖息地产生影响。白鳍豚主要栖息在弯曲河段和弯曲分汉河段的大回水区中，当河势改变，大回水区发生移动时，白鳍豚也相应迁移，迁移距离的长短，与大回水区移动距离长短有关。三峡水库下泄清水对河床的冲刷，有可能使大回水区变动，使白鳍豚的栖息地迁移，按最严重的估计，白鳍豚的栖息地有可能下移150余公里，不到现在分布范围的1／10。另外，航运条件改善后，航行船舶增多，有可能使白鳍豚发生意外死亡的几率增加。为保护这一濒临绝灭的珍贵水生动物，国家已在长江中游的螺山至新滩口江段和石首天鹅洲长江故道以及长江下游的铜陵江段分别建立了白鳍豚自然保护区。
分类地位：哺乳纲、鲸目、淡水豚科，白鳍豚属。
外部形态：体长2米，体重100～200千克。吻部狭长，约有30厘米，上下颔两边密排着130多棵圆锥形的牙齿，前额呈园形隆起。皮肤细腻光滑，背面是浅灰蓝色，腹面是洁白色，体表呈流线形，前肢为鳍肢，背鳍呈三角形。后肢退化，尾部未端左右平展，分成两叶，呈新月形。有一个长园形凹穴状的鼻子或呼吸孔长在头顶的左上方。眼睛只有绿豆粒一般大小，已经退化，位于嘴角的后上方。耳朵只有一个针眼大小的洞，位于眼的后方，外耳道已经消失。
分布地点：分布于我国长江自三峡的黄陵庙以下，一直到长江口，以及沿江的大型湖泊和较大的支流中。生活习性：视觉、听觉、嗅觉均己退化。在水中联系同类，趋避敌害，识别物体和探测食物等，完全依靠发出的声纳信号。性情温顺。以鲤鱼、鲢鱼、草鱼、青鱼、三角鲂、赤眼鳟、鲶鱼等淡水鱼类为食。每年有两次发情期，分别在3～5月和8～10月。怀孕期10～ll个月。每胎仅产1仔。生存状况：50年代时长江中尚可见到较大群体，但此后白鳍豚的数量却急剧下降，在沿江湖泊和支流中消失，长江中的个体己不足100只，仅残存在长江中游的枝城到南京一段。在我国《国家重点保护野生动物名录》中被列为1级保护动物；在《中国濒危动物红皮书·兽类》中被列为濒危种，列《华盛顿公约》附录：一类保护动物。 以上转自百度百科
白鳍豚似鱼非鱼，胎生、哺乳。为适应水中的生活环境，它逐渐变化成像鱼的样子，但却没有腮，而用肺呼吸。长有130颗牙齿，却不用它咀嚼，而是咬住食物以后，囫囵吞下。白鳍豚两个后肢蜕化消失，前肢演化为鳍，但内部结构却有和人手相似的桡骨、尺骨、腕骨、指骨。白鳍豚心脏分四腔，体温恒定。所有这一切都说明它是哺乳动物而并非鱼类。
背呈浅灰色或蓝色，腹面为纯白色，背鳍形如一个小三角，胸鳍宛如两只手掌，尾鳍扁平，中间分叉，善于游水，时速可达80千米左右。尾鳍不像鱼一样上下垂直，而是从水平方向分成两叶，可以上下摆动，从而推动躯体前进。加之它是标准的流线体型，皮肤构造特殊，所以游动速度特别快。它还能发出叫声，不同的声音反映其不同的感情。它可长到2～3米长，200～300公斤重，可额头上的一对眼睛却小如绿豆。它对气候变化特别敏感，风雨之前常频频露出水面，所以被鱼民看作可以呼风唤雨的“神鱼” 。
由于长期生活在浑浊的江水中，白鳍豚的视听器官已经退化。它眼小如瞎子，耳孔似针眼，位于双眼后下方。但大脑特别发达，声纳系统极为灵敏，头部还有一种超声波功能，能将江面上几万米范围内的声响迅速传入脑中。一旦遇上紧急情况，便立刻潜水躲避。白鳍豚耐寒，体温通常在36℃左右，喜欢生活在江河的深水区，很少靠近岸边和船只，但它时常游弋至浅水区，追逐鱼虾充饥。它的吻宽细长，上下颌长有130多枚圆锥形的同型齿，可它却懒得咀嚼,只管张口吞下鱼食，消化能力很强。白鳍豚往往成对或三五成群一起活动，但人们很少有机会看到它，只有在它露出水面呼吸时才能瞥见一眼。
今年曾进行过初测，当时就认为是最后的希望，现在大规模的探测之后，一头也没发现！难道我们连最后的希望也没了么？我们是历史的罪人……
News
Last hope for river dolphins [Nature 440, 1096-1097 (27 April 2006) doi:10.1038/4401096b]
Rex Dalton
Abstract
But preliminary survey fails to find any surviving 'baiji'.
The world's most critically endangered cetacean, the Chinese 'baiji' river dolphin, may finally have a chance of being saved from extinction. But it could be too late; researchers who carried out a nine-day pilot search for the dolphins last month didn't find a single one.
The freshwater baiji (Lipotes vexillifer) once thrived in their only habitat, the Yangtze River, which runs though central China. But fewer than 100 dolphins are thought to be left in the river, which has become a busy, polluted highway. "If the giant panda is China's symbol of the destruction of forests, the baiji stands for polluted waters," says Wang Ding, from the Wuhan Institute of Hydrobiology.
An international team of scientists, led by Ding, is hoping to catch the animals and release them in a safer place, possibly the Shishou reserve, which is a 20-kilometre arm off the Yangtze.
But first the researchers —from China, the United States, Britain and Switzerland — need to find out exactly how many of the dolphins remain and where they are. They are preparing to conduct a search of 1,700 kilometres of the river in November, but carried out a pilot survey in March to refine their techniques.
The baiji are so few and far between that the best way to spot them is with acoustic devices. But that's a challenge. "The river is so noisy you can't use traditional acoustic equipment," explains Jay Barlow, a marine mammalogist from the US National Marine Fisheries Service in La Jolla, California, who was on last month's cruise. He and his colleagues are working on a method to clean up recordings from hydrophones, to isolate the baiji's distinctive whistles.
The researchers were disappointed not to see a single baiji on their recent search, but their hopes are now focused on the full-scale survey in November. "If none are found then, the burden of proof will change," says Barlow. "The species will be considered extinct unless proven otherwise."
Dolphin feared extinct in polluted Yangtze
Overfishing and boat noise are killing aquatic mammals in Chinese river.
by Michael Hopkin news@nature.com
Human activity in China's Yangtze river is causing the region's dolphins to go extinct and more species will follow if fishing is not regulated, conservationists have warned.
Scientists on an expedition in China claimed this week that the freshwater baiji (Lipotes vexillifer), also called the river dolphin, should be declared 'functionally extinct' in the river. This means that even if a tiny handful of individuals still remains, their numbers will not be enough for them to bounce back. The creature does not live anywhere else making it the first cetacean to be driven to extinction by humans.
"There's no hope to save them," says August Pfluger, chief executive of the Baiji.org foundation, which has just completed a six-week survey of the Yangtze during which they found no baijis. The news is a blow to the team although a shorter survey in March also found no evidence of the dolphins, they had still hoped that around 100 dolphins might remain in the river (see ' Last hope for river dolphins').
Only the International Conservation Union can officially declare a species extinct, and only after it has not been sighted after several years of searching. "There's not enough data," says Rob Shore, freshwater programmes officer for the WWF in Godalming, UK. "But what we do know is that there are very, very few individuals left."
Thousands no more
What's more, another Yangtze mammal, the finless porpoise (Neophocaena phocaenoides), is also heading the same way, Pfluger says. "In the 1980s there were thousands and thousands," he says. "In the 1990s there were around 6,000, according to surveys. Now there are a
Overfishing and boat noise are killing aquatic mammals in Chinese river.
by Michael Hopkin news@nature.com
Human activity in China's Yangtze river is causing the region's dolphins to go extinct and more species will follow if fishing is not regulated, conservationists have warned.
Scientists on an expedition in China claimed this week that the freshwater baiji (Lipotes vexillifer), also called the river dolphin, should be declared 'functionally extinct' in the river. This means that even if a tiny handful of individuals still remains, their numbers will not be enough for them to bounce back. The creature does not live anywhere else making it the first cetacean to be driven to extinction by humans.
"There's no hope to save them," says August Pfluger, chief executive of the Baiji.org foundation, which has just completed a six-week survey of the Yangtze during which they found no baijis. The news is a blow to the team although a shorter survey in March also found no evidence of the dolphins, they had still hoped that around 100 dolphins might remain in the river (see ' Last hope for river dolphins').
Only the International Conservation Union can officially declare a species extinct, and only after it has not been sighted after several years of searching. "There's not enough data," says Rob Shore, freshwater programmes officer for the WWF in Godalming, UK. "But what we do know is that there are very, very few individuals left."
Thousands no more
What's more, another Yangtze mammal, the finless porpoise (Neophocaena phocaenoides), is also heading the same way, Pfluger says. "In the 1980s there were thousands and thousands," he says. "In the 1990s there were around 6,000, according to surveys. Now there are a
RELATED LINKS
Baiji.org
Dolphin Ring: river dolphins
Dolphin Research Centre
Understanding the baiji dolphin
Vaquita Marina
Baiji.org
Dolphin Ring: river dolphins
Dolphin Research Centre
Understanding the baiji dolphin
Vaquita Marina
Wuhan, 13 December 2006 – The Baiji Yangtze Dolphin is with all probability extinct! On Wednesday, in the city of Wuhan in central China, a search expedition, under the direction of the Institute for Hydrobiology Wuhan and the Swiss-based baiji.org Foundation, drew to a finish without any results. During the six-week expedition scientists from six nations desperately searched the Yangtze in vain.
No comments:
Post a Comment