| 摘要: |
| 早在50年代, Kellogg, Scheyil1l, Evans和Norris等人分别记录和研究了海豚的声信号, Schevill和 Lawrence通过实验有力地证实了海豚具有很好的回声定位能力。60年代以来,各国对海豚动物声呐进行了广泛研究,取得了很大进展。多年来,不少国外学者在实验工作的基础上对海豚的声发射与接收机制提出了一些近似的物理模型,不同程度地解释了一些海豚声呐系统中的现象,但与仿生学的综合研究的目标还相距甚远。对海豚水下声信号进行深入的定量测量与分析,仍是海豚仿生学中一项重要的基础工作,它对进一步研究、改进水下声学探测设备和强背景噪声下弱信号的识別与检测都有着实际指导意义。目前在大约五十余种海豚中,除对胆鼻海豚(Tursiops truncates)国外有过较多的研究外,对其他海豚的研究则很少。
江豚属齿鲸亚目,是体型最小的一种海豚。它主要分布在日本海和中国及东南亚各国沿岸海域,在中国长江口分布最为集中。每年3,4月份江豚到长江口一带生殖,有时沿江深入甚远。日本学者 Kazuhiro Mizue等(1968)和英国的Purves(1983)都对江豚的水下声信号作过记录与测量,但Kazuhiro Mizue等只记录到4kHz, Purves也只记录了30Hz-35kHz的信号;遗憾的是,由于信噪比太低,他们都没有进行详细的频谱分析。本实验所记录到的江豚声信号,由于记录器频带范围的限制,频率范围仅是40Hz-70kHz,其中包括了几种不同波形的较高频和低频脉冲信号,本实验对其频谱和周期作了较为详细的分析测量。 |
| 关键词: 江豚、声信号 |
| DOI： |
| 分类号: |
| 基金项目:中国科学院海洋研究所调查研究报告第1419号 |
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| RECORD AND ANALYSIS OF ACOUSTIC SIGNALS OF THE FINLESS BLACK PORPOISES (NEOPHOCAENA PHOCAENOIDES) |
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Zhang Sizhao, Song Huailong, Qi Meng'e, Xu Lanying, Xu Ruyan
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Institute of Oceanology, Academia Sinica
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| Abstract: |
| Measurements of echolocation signals of three finless black porpoises bred in a stream near the seashore show that finless black porpoises can emit not only high frequency pulse but also low frequency pulse. During the course of experiment, five different kinds of low frequency pulse and four different kinds of high frequency pulse were recorded. Oscillogram and spectrum were presented after these sound signals were analysed in laboratory. It was also found that the high frequency signals had a maximum energy between 60 and 70kHz which is much higher than echolocation signal of N. phocaenoides reported by Purves et al., yet the peak energies of low frequency pulses are different from each other. The time intervals between two successive pulses in a pulse train were found to be highly variable, the pulses of intervals from 4 μs to 9 μs account for about 62.4%. The sound presure levels of the echolocation signals in reference to 1 m distance in front of the animals’ rostrums were in general between 104dB and 107dB re. 1 μPa(0dB=1 μPa )and closely associated with animals' speed. The faster the speed, the higher the sound presure levels. |
| Key words: ACOUSTIC SIGNALS,FINLESS BLACK PORPOISES ,NEOPHOCAENA PHOCAENOIDES |
