Whale sightings during POLARSTERN cruise PS97 (ANT-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 PS97 (Punta Arenas – Punta Arenas) 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. The large number of unidentified sightings during this cruise resulted from sightings at great distances. Datasets are used in species distribution modelling and to inform interested parties about occurrences.极地海洋中鲸类分布与丰度的数据相当匮乏，因为实施标准勘测方法——线样带勘测（line-transect surveys）不仅难度极大，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，在所有极星号（Polarstern）科考航次期间，以电子方式记录所有偶遇鲸类目击记录。在极星号PS97航次（蓬塔阿雷纳斯—蓬塔阿雷纳斯）期间，当班航海官员借助安装在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信息。研究人员通过裸眼或手持7×50型双筒望远镜，将物种鉴定至尽可能低的分类学层级，并为其分配鉴定置信度等级。若条件允许，会统计动物个体数量；对于大型群体，则采用估算方式。若无法鉴定至物种层级，则采用下一级可识别的分类学类别进行记录。目击位置、日期与时间信息会在记录时，从船舶DAVIS-Ship系统（https://dship.awi.de/）自动传输至WALOG软件。若条件允许，会拍摄照片用于回溯分析。所有已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，我们会核查目击时间的合理性、记录位置、物种名称的标准化、目击时添加的补充注释，以及照片（若有）等额外信息，以验证或优化物种鉴定结果。本次航次中出现大量无法识别的目击记录，原因在于目击距离过远。本数据集可用于物种分布建模，并可为相关方提供鲸类出现情况的参考信息。