Around 176 500 whales were killed in the sub-Antarctic waters off South Georgia (South Atlantic) between 1904 and 1965. In recent decades, whales have once again become summer visitors, with the southern right whale (SRW) the most commonly reported species until 2011. Here, we assess the distribution, temporal pattern, health status and likely prey of SRWs in these waters, combining observations from a summertime vessel-based expedition to South Georgia, stable isotope data collected from SRWs and putative prey and sightings reports collated by the South Georgia Museum. The expedition used directional acoustics and visual surveys to localise whales and collected skin biopsies and photo-IDs. During 76 h of visual observation effort over 19 expedition days, SRWs were encountered 15 times (~31 individuals). Photo-IDs, combined with publicly contributed images from commercial vessels, were reconciled and quality-controlled to form a catalogue of 6 fully (i.e. both sides) identified SRWs and 26 SRWs identified by either left or right sides. No photo-ID matches were found with lower-latitude calving grounds, but 3 whales had gull lesions supporting a direct link with Península Valdés, Argentina. The isotopic position of SRWs in the South Georgia food web suggests feeding on a combination of copepod and krill species. Opportunistic reports of SRW sightings and associated group sizes remain steady over time, while humpback whales provide a strong contrast, with increased sighting rates and group sizes seen since 2013. These data suggest a plateau in SRWs and an increasing humpback whale presence in South Georgia waters following the cessation of whaling.

中文翻译：

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鲸鱼是否回到了工业捕鲸的历史热点？南乔治亚岛南露脊鲸 (Eubalaena australis) 的恢复模式

1904 年至 1965 年间，大约有 176,500 头鲸鱼在南乔治亚岛（南大西洋）附近的亚南极水域被捕杀。近几十年来，鲸鱼再次成为夏季游客，南露脊鲸 (SRW) 是最常报道的物种，直到2011 年。在这里，我们评估了这些水域中 SRW 的分布、时间模式、健康状况和可能的猎物，结合了夏季船基对南乔治亚岛的考察的观察结果、从 SRW 收集的稳定同位素数据以及由以下人员整理的推定猎物和目击报告南乔治亚博物馆。探险队使用定向声学和视觉调查来定位鲸鱼并收集皮肤活检和照片 ID。在 19 个探险日的 76 小时目视观察工作中，SRW 遇到了 15 次（约 31 个人）。照片身份证，结合公开提供的商船图像，经过协调和质量控制，形成 6 个完全（即两侧）识别的 SRW 和 26 个左侧或右侧识别的 SRW 的目录。没有发现与低纬度产犊场的照片身份证匹配，但 3 头鲸的海鸥病变支持与阿根廷巴尔德斯半岛的直接联系。SRW 在南乔治亚州食物网中的同位素位置表明以桡足类和磷虾的组合为食。随着时间的推移，SRW 目击事件和相关群体规模的机会报告保持稳定，而座头鲸提供了强烈的对比，自 2013 年以来目击率和群体规模有所增加。这些数据表明 SRW 处于稳定状态，而南乔治亚州水域的座头鲸数量也在增加捕鲸停止后。