Whale sightings during POLARSTERN cruise PS108 (ARK-XXXI/3)

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 PS108 (Tromsø - 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，通过当班航海官员以电子日志的形式，记录“极星号”（Polarstern）所有科考航次中偶遇的鲸类目击记录。在“极星号”PS108航次（特罗姆瑟-特罗姆瑟）期间，当班航海员利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），记录下裸眼目视的偶然目击情况。物种鉴定环节中，研究人员通过裸眼或手持双筒望远镜（7×50规格），尽可能将物种鉴定至最低分类学层级，并为其标注鉴定“置信度”等级。动物数量方面，若条件允许则直接计数，对于大型种群则进行估算。若无法将物种鉴定至具体物种层级，则将其归类至下一个可识别的分类学类别。目击位置、日期与时间信息会在记录生成时，自动从船舶DAVIS-Ship系统（https://dship.awi.de/）传输至WALOG软件。若条件允许，研究人员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校验，并转换为标准格式。具体校验工作包括：核查目击时间与位置的合理性、统一物种名称的标准化表述、审阅目击时添加的附加注释，以及核对照片（若有提供）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情况的信息参考。