2015台灣聲學學會第28屆學術研討會

2015/11/13

從海洋聲景探討中華白海豚的棲地特徵

 林子皓、周蓮香

國立台灣大學生態學與演化生物學研究所

Shane Guan

美國國家海洋漁業局保護資源辦公室

淺海聲景受到各地地理環境、生態群聚以及人為活動的影響而具有高度的變異性。許多海洋動物仰賴聲音訊息尋找活動方位,因此聲景可能是海洋動物棲地環境的指標之一。中華白海豚在台灣西岸的族群量少於80隻,主要使用3-15 kHz的哨聲溝通,並使用超音波的生物聲納進行回聲定位,因此聲音的感知對牠們相當重要。然而,目前仍不了解聲景是否在中華白海豚的棲地選擇中扮演重要的角色。本研究於苗栗海域利用SM2+錄音機長期收錄水下聲音,自動偵測回聲定位聲音,以了解中華白海豚的核心活動區域。長期時頻譜分析顯示,苗栗海域的聲景有明顯的日週期變化,且可在中華白海豚核心棲地與非核心棲地之間觀察到不同的頻譜特徵。核心棲地的中、高頻聲壓標準差較大,但平均值較低。顯示核心棲地的聲景特徵,以夜間的石首魚群體鳴唱,和白天較低的環境音為主。非核心棲地則有截然不同的聲景特徵,石首魚群體鳴唱較不明顯,但可偵測到大量槍蝦的寬頻脈衝聲波。未來許多離岸風力發電廠的開發工程將在西岸進行,本研究可協助相關單位了解中華白海豚棲地的海洋聲景變化。

關鍵字:中華白海豚、海洋聲景、生物音、時空變化、聲音偵測器

The soundscape in shallow marine environment displays a high level of spatial variation due to the regional change of geophysical environment, biological community, and human activity. Many marine animals rely on sounds for orientation; therefore the soundscape has been hypothesized as one of the environmental indicators. Indo-Pacific humpback dolphins in western Taiwan waters are critically endangered. The sound perception is essential for humpback dolphins, which communicate through 3-15 kHz whistles and echolocate through ultrasonic clicks. However, the importance of soundscape for their habitat selection remains unclear. In this study, SM2+ recorders were deployed in Miaoli waters to collect long-duration underwater recordings. Echolocation clicks were automatically detected to identify the core habitat of humpback dolphins. The long-term spectral average reveals that the soundscape in Miaoli waters evidently changed among the diurnal cycle. The spectral characteristic varied between the core habitat and non-core habitat. The soundscape at the core habitat was characterized by the higher standard deviations and lower means of SPL in mid- and high-frequency range. It indicates that the nighttime chorus of croakers and the low-level of ambient sound in the daytime represent the classical soundscape at the core habitat. On the contrary, the croaker chorus was less prominent at the non-core habitat. Instead, snapping shrimp sounds dominated the local soundscape. The current results can help understand the soundscape change of humpback dolphin habitat during the future development and operation of offshore wind farms.

Keywords:Sousa chinensis, marine soundscape, biological sound, temporal and spatial variations, sound detector

論文全文 (pdf)

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