Whale sightings during POLARSTERN cruise PS110 (ANT-XXXIII/1)

Data on whale distribution and abundance in the polar oceans is rather sparse, as implementing the standard surveying method, line-transect surveys, is challenging and costly. To overcome this problem, we initiated a program to electronically log all opportunistic cetacean sightings during all Polarstern expeditions through the nautical officer on watch. Opportunistic (visual) sightings by naked eye were logged during Polarstern Cruise PS110 (Bremerhaven – Cape Town) by the nautical officer on duty using a customized Software package (WALOG, WhAleLOGger) installed on a touch screen laptop located on the ship's bridge. Species were identified by naked eye or handheld binoculars (7x50) to the lowest possible taxonomical level and assigned a “certainty” level of identification. The number of animals were counted if possible or estimated for larger groups. Whenever identification to species level was not possible, the next identifiable taxonomical category was assigned. Information on sighting position, date and time are automatically transferred from the ship's DAVIS-Ship System (https://dship.awi.de/) to the WALOG software at the time of logging. Photographs were taken if possible for retrospective analysis. All data of acquired sightings were retrospectively validated by a marine biologist and converted to a standard format. To this end, plausibility of sighting time, location, standardization of species names, eventual comments added at the time of sighting, as well as additional information such as photographs (if available) were checked either to verify or improve species identification. Datasets are used in species distribution modelling and to inform interested parties about occurrences.

极地海域鲸类分布与丰度相关数据较为匮乏，原因在于标准调查方法——线样带调查（line-transect surveys）的实施难度高且成本高昂。为解决这一难题，我们启动了一项计划：依托值班航海官员，对所有极星号（Polarstern）科考航次中所有偶遇鲸类的目击记录进行电子化存档。在极星号PS110航次（不来梅港—开普敦航线）期间，值班航海官员借助安装于船舶驾驶台触摸屏笔记本电脑上的定制化软件包（WALOG，WhAleLOGger），对裸眼目视偶遇鲸类的目击情况进行了存档。研究人员通过裸眼或手持双筒望远镜（7×50规格）对鲸类进行鉴定，尽可能细化至最低分类阶元，并为其标注鉴定可信度等级。若可行则直接统计个体数量，对于大种群则进行估算。若无法鉴定至物种阶元，则标注可识别的次一级分类类别。目击位置、日期与时间等信息会在记录时，自动从船舶DAVIS-Ship系统（https://dship.awi.de/）同步至WALOG软件。若条件允许则拍摄照片，用于后续回溯分析。所有收集到的目击数据均由海洋生物学家进行回溯验证，并转换为标准格式。为此，研究人员将对目击时间与位置的合理性、物种名称的标准化处理、目击时添加的补充备注，以及照片（若有）等额外信息进行核查，以验证或优化物种鉴定结果。本数据集可用于物种分布模型构建，并可为相关方提供鲸类目击记录信息。