Under Contract to the Northeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 166 Water Street, Woods Hole, MA, 02543, USA.
Environmental Assessment Services, LLC, 350 Hills St., Suite 112, Richland, WA, 99354, USA.
Sci Rep. 2022 Oct 7;12(1):16821. doi: 10.1038/s41598-022-20868-3.
Sperm whales are an ideal species to study using passive acoustic technology because they spend the majority of their time underwater and produce echolocation clicks almost continuously while foraging. Passive acoustic line transect data collected between June and August 2016 were used to estimate a depth-corrected acoustic abundance and study the dive behaviour of foraging sperm whales in the western North Atlantic Ocean. 2D localizations (n = 699) were truncated at a slant range of 6500 m and combined with the multipath arrivals of surface reflected echoes to calculate 3D localizations (n = 274). Distance sampling using depth-corrected perpendicular distances resulted in a 10.5% change in the acoustic abundance estimate (2199 whales, CV = 14.6%) compared to uncorrected slant ranges (1969 whales, CV = 14.1%), and a detection function that was a better fit for the data. Sperm whales exhibited multiple foraging strategies, with bottom phases occurring at depths of 400-800, 800-1200, or > 1200 m, accounting for an average 39.2, 49.5, or 44.9% of the total recorded dive time, respectively. These results suggest that estimating 3D localizations using acoustic line transect data improves acoustic abundance estimation and can be used to answer population level questions about foraging ecology.
抹香鲸是使用被动声学技术进行研究的理想物种，因为它们大部分时间都在水下，并且在觅食时几乎连续不断地产生回声定位咔嗒声。2016 年 6 月至 8 月期间收集的被动声学线谱数据被用于估计经过深度校正的声学丰度，并研究北大西洋西部觅食抹香鲸的潜水行为。2D 定位（n=699）在斜距 6500 米处截断，并与表面反射回波的多路径到达相结合，计算 3D 定位（n=274）。使用经过深度校正的垂直距离进行距离抽样导致声学丰度估计值变化了 10.5%（2199 头鲸鱼，CV=14.6%），与未经校正的斜距相比（2199 头鲸鱼，CV=14.1%），以及更适合数据的检测函数。抹香鲸表现出多种觅食策略，底部阶段发生在 400-800、800-1200 或>1200 米的深度，分别占总记录潜水时间的平均 39.2、49.5 或 44.9%。这些结果表明，使用声学线谱数据估计 3D 定位可以提高声学丰度估计值，并可用于回答有关觅食生态学的种群水平问题。
