Marine ecosystems are experiencing rapid shifts under climate change scenarios and baleen whales are vulnerable to environmental change, although not all impacts are yet clear. We identify how the migration behaviour of the Chagos whale, likely a pygmy blue whale (Balaenoptera musculus brevicauda), has changed in association with shifts in environmental factors. We used up to 18 years of continuous underwater acoustic recordings to analyse the relationships between whale acoustic presence and sea surface temperature (SST), chlorophyll-a concentration, El-Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). We compared these relationships between two independent sites Diego Garcia southeast (DGS) and Diego Garcia northwest (DGN) where Chagos whales are detected and are suspected to move interannually across the Chagos-Laccadive ridge. We showed that the number of whale songs detected increased on average by 7.7% and 12.6% annually at DGS and DGN respectively. At the DGS site, Chagos whales shifted their arrival time earlier by 4.2 ± 2.0 days/year ± SE and were detected for a longer period by 7.3 ± 1.2 days/year ± SE across 18 years. A larger number of songs were detected during periods of higher chlorophyll-a concentration, and with positive IOD phases. At the DGN site, we did not see an earlier shift in arrival and songs were not detected for a longer period across the 13 years. Whale presence at DGN had a weaker but opposite relationship with chlorophyll-a and IOD. The oceanic conditions in the Indian Ocean are predicted to change under future climate scenarios and this will likely influence Chagos whale migratory behaviour. Understanding how environmental factors influence whale movement patterns can help predict how whales may respond to future environmental change. We demonstrate the value of long-term acoustic monitoring of marine fauna to determine how they may be affected by changing environmental conditions.

在气候变化情景下，海洋生态系统正在经历快速变化，须鲸很容易受到环境变化的影响，尽管并非所有影响都还很清楚。我们确定了查戈斯鲸的迁徙行为，可能是侏儒蓝鲸（短尾鲸鱼)，随着环境因素的变化而变化。我们使用长达 18 年的连续水下声学记录来分析鲸鱼声学存在与海面温度 (SST)、叶绿素 a 浓度、厄尔尼诺南方涛动 (ENSO) 和印度洋偶极子 (IOD) 之间的关系。我们比较了迭戈加西亚东南 (DGS) 和迭戈加西亚西北 (DGN) 两个独立地点之间的这些关系，在这些地点检测到查戈斯鲸，并怀疑它们每年跨过查戈斯-拉卡迪夫山脊。我们发现，在 DGS 和 DGN 检测到的鲸歌数量平均每年分别增加 7.7% 和 12.6%。在 DGS 站点，查戈斯鲸的到达时间提前了 4.2 ± 2.0 天/年 ± SE，并在更长时间内被检测到了 7.3 ± 1。2 天/年 ± SE 跨越 18 年。在较高的叶绿素-a 浓度期间检测到大量歌曲，并且具有正 IOD 阶段。在 DGN 站点，我们没有看到更早的到达率变化，并且在 13 年的较长时间内没有检测到歌曲。DGN 的鲸鱼存在与叶绿素-a 和 IOD 的关系较弱但相反。印度洋的海洋条件预计会在未来的气候情景下发生变化，这可能会影响查戈斯鲸的迁徙行为。了解环境因素如何影响鲸鱼的运动模式可以帮助预测鲸鱼如何应对未来的环境变化。我们展示了对海洋动物群进行长期声学监测的价值，以确定它们如何受到不断变化的环境条件的影响。在较高的叶绿素-a 浓度期间检测到大量歌曲，并且具有正 IOD 阶段。在 DGN 站点，我们没有看到更早的到达率变化，并且在 13 年的较长时间内没有检测到歌曲。DGN 的鲸鱼存在与叶绿素-a 和 IOD 的关系较弱但相反。印度洋的海洋条件预计会在未来的气候情景下发生变化，这可能会影响查戈斯鲸的迁徙行为。了解环境因素如何影响鲸鱼的运动模式可以帮助预测鲸鱼如何应对未来的环境变化。我们展示了对海洋动物群进行长期声学监测的价值，以确定它们如何受到不断变化的环境条件的影响。在较高的叶绿素-a 浓度期间检测到大量歌曲，并且具有正 IOD 阶段。在 DGN 站点，我们没有看到更早的到达率变化，并且在 13 年的较长时间内没有检测到歌曲。DGN 的鲸鱼存在与叶绿素-a 和 IOD 的关系较弱但相反。印度洋的海洋条件预计会在未来的气候情景下发生变化，这可能会影响查戈斯鲸的迁徙行为。了解环境因素如何影响鲸鱼的运动模式可以帮助预测鲸鱼如何应对未来的环境变化。我们展示了对海洋动物群进行长期声学监测的价值，以确定它们如何受到不断变化的环境条件的影响。