Whale sightings during POLARSTERN cruise PS135/1@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 PS135/1 (Punta Arenas - Mindelo) 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——截线抽样调查（line-transect surveys）——实施难度大且成本高昂。为破解这一困境，我们启动了一项专项计划：通过值班航海官员，在所有Polarstern（极星号）科考航次中，以电子形式记录所有偶遇鲸类目击事件。在Polarstern航次PS135/1（蓬塔阿雷纳斯—明德卢航线）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），完成了裸眼目视偶遇目击信息的记录工作。研究人员通过裸眼或手持7×50型双筒望远镜，将目击物种鉴定至尽可能精细的分类学层级，并为其赋予对应的鉴定置信度等级。若条件允许，会对目击动物的数量进行直接计数；针对大型群体，则采用估算方法。若无法将物种鉴定至种级水平，则将其归类至次一级可识别的分类单元。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/）同步至WALOG软件。若条件许可，研究人员会拍摄目击场景的照片，用于后续回溯分析。所有采集到的目击数据均由海洋生物学家开展回溯验证，并转换为统一标准格式。验证过程中，需逐一核查目击时间与位置的合理性、物种名称的标准化规范、目击时添加的附带备注，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研究，同时可为相关方提供鲸类出现情况的参考信息。