Soldevilla Melissa S, Baumann-Pickering Simone, Cholewiak Danielle, Hodge Lynne E W, Oleson Erin M, Rankin Shannon
Southeast Fisheries Science Center, National Marine Fisheries Services, National Oceanic and Atmospheric Administration, 75 Virginia Beach Drive, Miami, Florida 33149, USA.
Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0205, USA.
J Acoust Soc Am. 2017 Aug;142(2):599. doi: 10.1121/1.4996002.
Discrimination of bioacoustic signals to the species or population level is critical for using passive acoustic monitoring to study cetacean ecology. Risso's dolphins off southern California have distinctive peaks and notches in their echolocation clicks, but it was unknown whether Risso's dolphins from other geographic areas have similarly distinctive click spectra and whether populations are acoustically distinct. This study investigates using clicks for species and population identification by characterizing the spectral structure of Risso's dolphin echolocation clicks recorded over wide-ranging geographic regions including the U.S. waters of the North Atlantic Ocean, Gulf of Mexico, and North Pacific Ocean; and international waters of the Eastern Tropical Pacific. All recordings with Risso's dolphin clicks exhibited the spectral peak and notch pattern described off southern California, indicating the presence of peak banding patterns is useful for species discrimination. Geographic regions were a significant explanatory factor for variability in the frequencies of click spectral peaks, with relatively higher frequency peaks and notches found off Hawaii compared to California waters and off the southeast U.S. compared to the Gulf of Mexico. In the North Atlantic Ocean, a latitudinal cline in frequencies was evident. Potential causes of acoustic variation within and among acoustic encounters are evaluated.
将生物声学信号区分到物种或种群水平对于利用被动声学监测研究鲸类生态至关重要。南加利福尼亚附近的里氏海豚在其回声定位咔嗒声中有独特的峰值和凹口，但来自其他地理区域的里氏海豚是否具有类似独特的咔嗒声频谱以及种群在声学上是否有差异尚不清楚。本研究通过对在广泛地理区域记录的里氏海豚回声定位咔嗒声的频谱结构进行表征，来研究利用咔嗒声进行物种和种群识别，这些地理区域包括北大西洋、墨西哥湾和北太平洋的美国海域，以及东热带太平洋的国际水域。所有带有里氏海豚咔嗒声的记录都呈现出南加利福尼亚附近所描述的频谱峰值和凹口模式，表明峰值频带模式的存在有助于物种区分。地理区域是咔嗒声频谱峰值频率变异性的一个重要解释因素，与加利福尼亚海域相比，夏威夷附近发现的峰值和凹口频率相对较高，与墨西哥湾相比，美国东南部附近也是如此。在北大西洋，频率的纬度梯度很明显。对声学相遇内部和之间声学变化的潜在原因进行了评估。
