Whale sightings during POLARSTERN cruise PS122/4 (MOSAiC)@en

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 PS122/4 (Longyearbyen, Svalbard and Jan Mayen - Arctic Ocean) 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——线样调查（line-transect surveys）的实施难度大且成本高昂。为解决这一困境，我们启动了一项计划，通过当班航海官员记录所有Polarstern号科考航次中偶遇的鲸类目击信息，并以电子日志形式留存。在Polarstern号PS122/4航次（航线为朗伊尔城、斯瓦尔巴群岛与扬马延岛——北冰洋）期间，当班航海官员使用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，鲸类目击记录器），记录了裸眼目视的偶遇鲸类目击情况。研究人员通过裸眼或手持双筒望远镜（7×50规格）对物种进行鉴定，尽可能确定至最低分类学层级，并为其赋予鉴定可信度等级。若条件允许，则对动物个体数量进行计数；对于大型群体，则采用估算方式。若无法鉴定至物种层级，则将其归类至可识别的次一级分类单元。目击位置、日期与时间信息会在记录时，从船舶DAVIS船舶系统（DAVIS-Ship System，https://dship.awi.de/）自动同步至WALOG软件。若条件允许，将拍摄照片用于回溯性分析。所有获取的目击数据均由海洋生物学家进行回溯性验证，并转换为标准格式。为此，研究人员会核查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，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，并可向相关方通报鲸类目击事件的发生情况。