Abstract: 　　The line transect samplingwas employed to survey the population density and size of bot t lenose dolphin (T u rsiop s truncatus) in the area between 25°～ 30°N ,w- est of 125°Ein the East China Sea, which generated a minimum estimates of 0.140 0 ( individual/km²) and 9 940 individuals respect ively. The population density of T ursiop s in this waters decreased along with the increase of latitude (from south to north) , however no obvious distributional pattern existed in the longitude direction. This is the firsttime to use line t ransect sampling method to survey the population size, and distributional characteristics of bottlenose dolphins in the China Seas.

Key words: Bottlenose dolphin (Tursiops truncatus), Line transect sampling, Population size, Distribution

摘要： 运用截线抽样法调查了北纬25°～ 30°, 东经125°以西的东海水域中瓶鼻海豚在夏季7～ 9月间的种群密度和数量, 得出的最小估计值分别为0.140 0头/km² 和9 940头。瓶鼻海豚在该水域的分布特点为: 随纬度增加(由南向北) 密度逐渐减少, 而在经度方向上则没有明显的密度变化规律。

关键词: 瓶鼻海豚, 截线抽样法, 种群数量, 分布