There are multiple blue whale acoustic populations found across the Southern Hemisphere. The different subspecies of blue whales feed in separate areas, but during their migration to lower-latitude breeding areas each year, Antarctic blue whales become sympatric with pygmy and Chilean blue whales. Few studies have compared the degree of this overlap of the Southern Hemisphere blue whale subspecies across ocean basins during their migration. Using up to 16 years of acoustic data, this study compares the broad seasonal presence of Antarctic blue whales, Chilean blue whales, and Southeast Indian Ocean (SEIO) pygmy blue whales across the Pacific and Indian Oceans. Antarctic blue whales were sympatric with the other two blue whale subspecies during the migrating season of every year. Despite this overlap, Chilean and pygmy blue whale detections peaked earlier during the austral autumn (April–May) while Antarctic blue whale detections peaked later during the austral winter (June). Chilean (Pacific Ocean) and SEIO (Indian Ocean) pygmy blue whales showed similar seasonal patterns in detections despite occurring in different ocean basins. Though we have shown that Antarctic blue whales have the potential to encounter other blue whale subspecies during the breeding season, these distinct groups have remained acoustically stable through time. Further understanding of where these whales migrate will enable a better insight as to how these subspecies continue to remain separate.

在整个南半球发现了多个蓝鲸声学种群。蓝鲸的不同亚种在不同的地区觅食，但在每年向低纬度繁殖区迁徙的过程中，南极蓝鲸与侏儒蓝鲸和智利蓝鲸共存。很少有研究比较南半球蓝鲸亚种在迁徙过程中跨越海洋盆地的这种重叠程度。本研究使用长达 16 年的声学数据，比较了横跨太平洋和印度洋的南极蓝鲸、智利蓝鲸和东南印度洋 (SEIO) 侏儒蓝鲸的广泛季节性存在。南极蓝鲸在每年的迁徙季节与其他两个蓝鲸亚种同居。尽管有这种重叠，智利和侏儒蓝鲸的发现在南部秋季（4 月至 5 月）较早达到峰值，而南极蓝鲸的发现则在南部冬季（6 月）较晚达到峰值。尽管发生在不同的海洋盆地，智利（太平洋）和 SEIO（印度洋）侏儒蓝鲸在检测中显示出相似的季节性模式。虽然我们已经证明南极蓝鲸有可能在繁殖季节遇到其他蓝鲸亚种，但这些不同的群体在时间上一直保持着声学稳定。进一步了解这些鲸鱼的迁徙地点将有助于更好地了解这些亚种如何继续保持独立。尽管发生在不同的海洋盆地，智利（太平洋）和 SEIO（印度洋）侏儒蓝鲸在检测中显示出相似的季节性模式。虽然我们已经证明南极蓝鲸有可能在繁殖季节遇到其他蓝鲸亚种，但这些不同的群体在时间上一直保持着声学稳定。进一步了解这些鲸鱼的迁徙地点将有助于更好地了解这些亚种如何继续保持独立。尽管发生在不同的海洋盆地，智利（太平洋）和 SEIO（印度洋）侏儒蓝鲸在检测中显示出相似的季节性模式。虽然我们已经证明南极蓝鲸有可能在繁殖季节遇到其他蓝鲸亚种，但这些不同的群体在时间上一直保持着声学稳定。进一步了解这些鲸鱼的迁徙地点将有助于更好地了解这些亚种如何继续保持独立。