Seasonal variation in the acoustic presence of blue whale calls has been widely reported for feeding grounds worldwide, however variation over the submonthly scale (several days to <1 month) has been examined to a much lesser extent. This study combines passive acoustic, hydroacoustic, and in situ oceanographic observations collected at a mooring in the Corcovado Gulf, Northern Chilean Patagonia, from January 2016-February 2017, to examine the temporal variation in blue whale acoustic occurrence and prey backscatter over seasonal and submonthly scales. Time series data for a) Southeast Pacific blue whale song calls and D-calls, b) zooplankton backscatter, c) tidal amplitude, and d) meridional and zonal wind stress were examined visually for seasonal trends. To examine submonthly timescales over the summer feeding season (January-June), wavelet transforms and wavelet coherence were applied; generalized linear models (GLM) were also applied. There was a 3-month lag between the seasonal onsets of high zooplankton backscatter (October) and blue whale acoustic presence (January), and an almost immediate drop in blue whale acoustic presence with the seasonal decrease of backscatter (June). This may be due to the use of memory by animals when timing their arrival on the feeding ground, but the timing of their departure may be related to detection of low prey availability. Over the summer feeding season, blue whale acoustic presence was strongly associated with zooplankton backscatter (GLM coefficient p ≪ 0.0001). Song calls followed a seasonal cycle, but D-calls appeared to respond to short term variations in environmental conditions over submonthly scales. Results suggest that spring tides may increase prey aggregation and/or transport into the Corcovado Gulf, leading to increased blue whale acoustic presence over 15-day or 30-day cycles; and short-lived events of increased wind stress with periodicities of 2–8 days and 16–30 days, may also contribute to the aggregation of prey. We discuss the strengths and limitations of coupling passive and active acoustic data to examine drivers of blue whale distribution.

蓝鲸鸣叫声的季节性变化已被广泛报道为世界各地的觅食场，但对次月尺度（几天到 <1 个月）的变化进行的研究程度要小得多。这项研究结合了被动声学、水声学和原位2016 年 1 月至 2017 年 2 月，在智利巴塔哥尼亚北部科尔科瓦多湾的一个系泊处收集的海洋观测数据，以检查蓝鲸声学发生和猎物反向散射在季节性和次月尺度上的时间变化。时间序列数据 a) 东南太平洋蓝鲸鸣叫和 D 呼叫，b) 浮游动物反向散射，c) 潮汐振幅，以及 d) 经向和纬向风应力的季节性趋势视觉检查。为了检查夏季饲喂季节（1 月至 6 月）的次月时间尺度，应用了小波变换和小波相干性；广义线性模型（GLM）也被应用。在高浮游动物反向散射（10 月）和蓝鲸声学存在（1 月）的季节性发作之间存在 3 个月的滞后，随着反向散射的季节性减少（6 月），蓝鲸声学存在几乎立即下降。这可能是由于动物在定时到达觅食地时使用了记忆，但它们离开的时间可能与低猎物可用性的检测有关。在夏季觅食季节，蓝鲸声学存在与浮游动物反向散射密切相关（GLM 系数 p ≪ 0.0001）。歌曲呼叫遵循季节性周期，但 D 呼叫似乎对环境条件的短期变化在次月范围内做出反应。结果表明，大潮可能会增加猎物聚集和/或向科尔科瓦多湾的运输，导致蓝鲸在 15 天或 30 天周期内的声学存在增加；周期性为 2-8 天和 16-30 天的短期风应力增加事件也可能导致猎物聚集。我们讨论了耦合被动和主动声学数据以检查蓝鲸分布的驱动因素的优势和局限性。