Acoustic survey of baiji in their historic habitat of the Yangtze River

利用先进的水声技术揭示了濒危淡水鲸目动物的分布。提供了鲸类在整个长江流域的宏观尺度分布和高密度区域的微观尺度分布。采用拖曳式水下传声器对长江长江沿岸宜昌至上海一带的白暨豚和江豚的历史栖息地进行了调查。结果表明，白暨豚濒临灭绝，江豚数量迅速减少。在长江中游高密度热点水域进行了长期静声波观测。在此基础上，提出了一种将声检测率转换为现有动物数量的真实密度的模型。在同一段进行了广泛的拖曳声学测量，并提供了鼠海豚的详细分布图。去年，在长江中下游全长1100公里的武汉至上海区间，以货船为平台进行了定期自动测量。该方法具有成本效益，可用于小齿状突的大范围监测，目前已在世界范围内得到应用。

Distribution of endangered freshwater cetaceans was revealed by cutting-edge underwater acoustic technology. Macro scale distribution of cetaceans in the entire Yangtze River and micro scale distribution in a high density area were provided. Historic habitat of baiji and Yangtze finless porpoises were surveyed from Yichang, nearby three gorges dam, to Shanghai, using towing type underwater microphone. Results suggested extinction of baiji and quick reduction of finless porpoises. Log-term stationary acoustic observation had been conducted at the hot spot, high density waters, in the middle of the Yangtze River. Using the outcomes, a model to convert acoustic detection rate to real density of existing number of animals was proposed. Extensive towing acoustic survey was conducted in the same section and provided detail map of distribution of porpoises. In the last year, periodical automatic surveys using a cargo ship as a platform of the acoustic device were conducted from Wuhan to Shanghai, 1100km stretch of the middle and lower reached of the Yanzgter River. This method is cost effective and useful for range-wide monitoring of small odontocetes, which has been applied worldwide in these days.