Whale sightings during POLARSTERN cruise ARK-XXVII/2 (PS80/2)

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 ARK-XXVII/2 (Longyearbyen -Tromsø ) 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.极地海洋中鲸类（cetacean）的分布与丰度数据相当匮乏，因为标准调查方法——线样带调查（line-transect surveys）——的实施难度大且成本高昂。为解决这一难题，我们启动了一项计划，通过值班航海官员，在所有极地号（Polarstern）科考航次期间，以电子方式记录所有偶遇鲸类目击记录。在极地号ARK-XXVII/2航次（朗伊尔城—特罗姆瑟航线）中，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），以裸眼记录偶遇目视目击事件。项目组成员将通过裸眼或手持7×50双筒望远镜，将目击物种鉴定至尽可能低的分类学层级，并赋予对应的鉴定置信度等级。若可直接计数则统计动物个体数量，对于大型种群则进行估算；若无法将目击物种鉴定至物种层级，则将其归类至下一级可识别的分类单元。目击记录的位置、日期与时间将在记录生成时，自动从船舶DAVIS-Ship系统（https://dship.awi.de/）同步至WALOG软件。若条件允许，会拍摄照片用于回溯分析。所有获取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，我们将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。本数据集可应用于物种分布建模，并可为相关方提供鲸类出现记录的信息参考。